- Email: [email protected]
Synthesis and photophysical properties of GemPhos noble metal complexes
Accepted Manuscript Synthesis and Photophysical Properties of GemPhos Noble Metal Complexes Christian Sarcher, Sebastian Bestgen, Florian C. Falk, Sergei Lebedkin, Jan Paradies, Peter W. Roesky PII:
S0022-328X(15)00111-4
DOI:
10.1016/j.jorganchem.2015.02.033
Reference:
JOM 18934
To appear in:
Journal of Organometallic Chemistry
Received Date: 18 December 2014 Revised Date:
20 February 2015
Accepted Date: 21 February 2015
Please cite this article as: C. Sarcher, S. Bestgen, F.C. Falk, S. Lebedkin, J. Paradies, P.W. Roesky, Synthesis and Photophysical Properties of GemPhos Noble Metal Complexes, Journal of Organometallic Chemistry (2015), doi: 10.1016/j.jorganchem.2015.02.033. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
Synthesis and Photophysical Properties of GemPhos Noble Metal Complexes Christian Sarcher,[a] Sebastian Bestgen,[a] Florian C. Falk,[c] Sergei Lebedkin,*[b] Jan
RI PT
Paradies,[c,d] and Peter W. Roesky[a]*
[a] Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße
SC
15, 76131 Karlsruhe (Germany), Fax: (+)49 721 6084 4854, E-mail: [email protected]
M AN U
[b] Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 2, 76131 Karlsruhe (Germany) and Institut für Nanotechnologie Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76021 Karlsruhe (Germany).
TE D
[c] Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany).
EP
[d] Institut für Organische Chemie, Universität Paderborn, Warburger Str. 100, 33098
AC C
Paderborn (Germany).
ACCEPTED MANUSCRIPT Abstract GemPhos, a diphosphine ligand with a rigid paracyclophane scaffold, was used to prepare complexes of the noble metals gold, palladium, and platinum. The reaction of GemPhos with
RI PT
[Au(tht)2][ClO4] (tht = tetrahydrothiophene) surprisingly yielded a mononuclear charge separated gold compound [(GemPhos)Au][ClO4], in which the gold atom exhibits an uncommon trigonal planar coordination geometry. Furthermore, similar palladium [(GemPhos)(PdCl2)] and platinum [(GemPhos)(PtCl2)] complexes were obtained in very good
SC
yields by the reaction of GemPhos with [MCl2(COD)] (M = Pd, Pt; COD = 1,5-
M AN U
cyclooctadiene) in hot DMSO. All compounds were fully characterized by analytical and spectroscopic techniques and their solid-state structures were established by single X-ray crystallography. Their photoluminescent properties were measured at low and ambient
AC C
EP
TE D
temperatures, revealing different behavior depending on the metal and coordination mode.
ACCEPTED MANUSCRIPT Introduction Bidentate ligands with phosphorus donor atoms are well-established in organometallic chemistry [1-4]. In combination with noble metals they are widely used, for instance, in
RI PT
homogeneous catalysis [5]. By changing the phosphorus' substitutes, the electronic and steric properties of the ligand can be modified, which affects the bite angle and coordination behavior in metal complexes. Especially in homogeneous catalysis, the selectivity and reaction rates can be explicitly diversified. Also the solubility of the catalyst depends on the
SC
properties of the phosphine ligand. The noble metals gold, palladium and platinum are of
M AN U
particular interest with respect to hetero- and homogeneous catalysis [6-8], as well as their photoluminescent (PL) properties [9-15]. Nowadays, the synthesis and application of gold compounds is one of the rapidly progressing fields in organometallic chemistry, as evidenced by the strongly increasing number of publications dealing with various gold-containing substances. This is mirrored by a significant number of reviews dealing with various topics of
TE D
gold chemistry [13, 16-44]. The emerging interest is caused by the unique properties that gold compounds exhibit, i.e. they are catalytically active in various organic transformations [42, 44] and show a phenomenon that is described as aurophilicity [39, 43]. This closed shell d10-
EP
d10 dispersion interaction is yet not fully understood, notably with respect to the influence of
AC C
such metal-metal interactions on the photophysical and catalytic properties. Additionally, palladium
and
platinum
compounds
are
widely
used
in
cross-coupling
or
hydrogenation/hydroformylation reactions [6-8], which find many applications in synthetic chemistry and industrial processes. Since we are interested in the photoluminescent behavior of metal complexes, dinuclear gold compounds of the very similar ligands PhanePhos [45] and GemPhos [46] have been examined. Quantum chemical and spectroscopic investigations revealed that the excited states of both compounds are highly influenced by the intramolecular gold distances [47]. However, their computed excitation energies, and consequently the absorption/ photoluminescence spectra, were quite similar. In this contribution we report three
ACCEPTED MANUSCRIPT new complexes of palladium, platinum and gold which were analyzed by analytical and spectroscopic techniques including photoluminescence (PL) spectroscopy. This work
RI PT
continues our studies on diphosphine ligands with a rigid paracyclophane scaffold.
Results and Discussion
Recently, the influence of aurophilic interactions on the catalytic and photophysical properties
complexes
[PhanePhos(AuCl)2]
and
SC
of dinuclear gold compounds has been investigated by us on two structurally very similar [GemPhos(AuCl)2]
(Scheme
1)
[47].
M AN U
[PhanePhos(AuCl)2] and [GemPhos(AuCl)2] coincide in their molecular formula and primarily differ in their intermetallic distances and thus allowed systematic studies with
EP
TE D
respect to hydroamination reactions and photoluminescent behavior [47].
compounds
without ([PhanePhos(AuCl)2]) and with
AC C
Scheme 1: Dinuclear gold,
([GemPhos(AuCl)2]) aurophilic interactions, respectively.
Since [GemPhos(AuCl)2] was successfully applied as a catalyst in the inter- and intramolecular hydroamination of alkynes and olefins [48] and exhibited bright-green phosphorescence in the solid state at low temperatures, we felt challenged to extend our studies on paracyclophane-based gold complexes and those of palladium and platinum. It is well-known that homoleptic gold phosphine complexes [P-Au-P] can be obtained by using
ACCEPTED MANUSCRIPT [Au(tht)2][ClO4] (tht = tetrahydrothiophene) as a starting material because the two labile tht ligands can be easily replaced by stronger σ-donors such as phosphines or NHCs. Surprisingly, the reaction of GemPhos and [Au(tht)2][ClO4] in a 1:1 ratio did not yield the expected dinuclear complex [(GemPhos)2Au2][ClO4]2. Instead, a heteroleptic gold(I)
RI PT
complex, [(GemPhos)Au(tht)][ClO4] (1), was isolated. In 1 the gold atom features a trigonal planar coordination environment (Scheme 2). Molecular gold(I) compounds with a closed shell d10 electronic configuration are linearly coordinated in most cases. However, gold(I)
SC
complexes possessing higher coordination numbers also exist, although they are less common
TE D
M AN U
[49-52].
Scheme 2: Synthesis of the heteroleptic complex [(GemPhos)Au(tht)][ClO4] (1).
EP
Complex 1 was fully characterized by analytical and spectroscopic techniques. The 1H NMR
AC C
spectrum is in accordance with the proposed structure, whereas the resonances for the ethylene units, as well as those for the tht ligand, are shifted slightly upfield compared to the starting materials. In the 31P{1H} NMR spectrum, a singlet is observed at 42.7 ppm, which is shifted considerably downfield (+ 50.4 ppm), compared to the free ligand GemPhos [46] and to [GemPhos(AuCl)2] (+ 13.4 ppm) [47] and thus indicating the coordination of the gold atom. As the complex is of ionic nature, ESI-MS was conducted to confirm the structure. An ion peak including the correct isotopic distribution is observed at m/z = 773.21 amu, which corresponds to the [(GemPhos)Au]+ fragment and further demonstrates the lability of the tht ligand in solution. The structure of 1 was unambiguously determined by single crystal X-ray
ACCEPTED MANUSCRIPT crystallography (Figure 1). The complex crystallizes in the orthorhombic space group P212121 with four molecules of 1 as well as eight molecules of dichloromethane in the unit cell. The Au-P distances slightly differ from each other with Au-P1 2.339(2) Å and Au-P2 2.342(2) Å, but they are in the expected range for Au-P bonds. The Au-S bond (2.428(2) Å) is elongated
RI PT
compared with [AuCl(tht)] (2.26 Å) indicating that the tht ligand is very weakly bound to the gold atom. The central atom itself exhibits an unusual trigonal planar coordination sphere. The gold atom and the donor atoms have an exact coplanar arrangement as shown by the
SC
angular sum of 359.99°. The P1-Au-P2 angle (115.99(7)°) is slightly more acute than the
AC C
EP
TE D
Au-S) and 121.44(9)° (P2-Au-S)).
M AN U
ideal angle of 120°. In contrast, the P-Au-S angles are somewhat widened (122.56(8)° (P1-
FIgure 1: Solid-state structure of [(GemPhos)(tht)Au][ClO4] (1). Hydrogen atoms and solvent molecules are omitted for clarity. Selected bond lengths [Å] and angles [°]: Au-S 2.427(2), Au-P1 2.339(2), Au-P2 2.342(2), P1-C1 1.838(8), P1-C13 1.833(8), P1-P2 3.9698(5); P1-Au-P2 115.99(7), P1-Au-S 122.55(8), P2-Au-S 121.45(9), Au-S-C41 112.7(4), Au-S-C44 109.6(4), Au-P1-C1 110.6(3), Au-P1-C7 118.3(3), Au-P1-C13 113.9(3), Au-P2C28 111.5(3), Au-P2-C29 114.5(3), Au-P2-C35 114.8(3), C1-P1-C7 104.4(4), C1-P1-C13
ACCEPTED MANUSCRIPT 105.0(4), P1-C13-C14 121.8(6), C13-C14-C15 122.0(8), C14-C15-C21 121.0(9), C15-C21C22 111.5(8), C21-C22-C26 114.7(8).
Compared with the trigonal planar coordinated gold complex [Au(PPh3)2(SCN)] [49] (P-Au-P
RI PT
127.8(1)°), the rigid backbone of the GemPhos ligand does not allow significant flexibility. The phosphine units are forced into close proximity upon gold coordination, as illustrated by the intramolecular P1-P2 distance of 3.9698(5) Å. This is considerably shorter than in
SC
[GemPhos(AuCl)2] [47] and even shorter than in the free ligand [46]. The observed
M AN U
coordination mode can be ascribed to the rigidity of the ligand. A weakly coordinating ligand is attached to the gold atom to complete the coordination sphere.
As a bidentate phosphine, GemPhos should be a suitable ligand for noble metals. Some of us have already reported the addition of [Pd(OAc)2] to GemPhos followed by oxidative addition
TE D
of chlorobenzene to the palladium atom [46]. Furthermore, the amidination of aryl chlorides by using the unsymmetrically substituted PhCy-GemPhos/Pd(OAc)2, which proved to be a highly active catalytic system, was investigated [53]. Since we were interested in
EP
photophysical properties, palladium and platinum complexes of the GemPhos ligand were prepared. As starting materials, the commercially available cyclooctadiene complexes
AC C
[MCl2(COD)] (M = Pd, Pt; COD = 1,5-cyclooctadiene) were chosen. Since all attempts to obtain the desired complexes by stirring a solution of metal precursor and phosphine ligand in dichloromethane failed, the reactions were conducted in DMSO at higher temperatures. Recrystallization of the crude products from hot DMSO resulted in the complexes [GemPhos(MCl2)] (Pd (2), Pt (3)) as single crystalline materials in very good yields (84% (2), 81% (3), Scheme 3).
RI PT
ACCEPTED MANUSCRIPT
SC
Scheme 3: Synthesis of [(GemPhos)(PdCl2)] (2) and [(GemPhos)(PtCl2)] (3).
Both compounds were fully characterized by analytical and spectroscopic techniques. Not
M AN U
surprisingly, the 1H NMR spectra of 2 and 3 are very similar. For the palladium complex, a sharp singlet is observed at 37.8 ppm in the 31P{1H} NMR spectrum, indicating the magnetic equivalency of the phosphorus atoms as well as metal complexation since the resonance is shifted significantly downfield (+30.1 ppm) as compared to the free ligand. The
31
P{1H}
TE D
NMR spectrum of 3 exhibits a singlet at 15.9 ppm flanked by platinum satellites with 1JPtP = 3656 Hz as the phosphines are coupled to the NMR-active isotope NMR and
31
195
Pt. Furthermore,
195
Pt
P{1H}/195Pt HMQC experiments were conducted to confirm the proposed
EP
structure. Because of the magnetic equivalency of both phosphorus atoms, a triplet at -4575 ppm is observed in
195
Pt NMR spectrum with the same coupling constant of 1JPtP = 3656 Hz.
AC C
The expected cross peaks can be found in the HMQC spectrum, further proving the direct PtP coupling (Figure 2).
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
TE D
Figure 2: 31P{1H}/195Pt HMQC NMR spectrum of 3 in DMSO-d6.
In the solid state, both compounds are isostructural and crystallize in the monoclinic space group P21/c with four molecules in the unit cell (Figures 3). The M-Cl distances are very
EP
similar for both complexes and vary between 2.3449(10) Å to 2.3546(10) Å (Pd-Cl) and 2.3452(14) Å to 2.3590(13) Å (Pt-Cl). The same is observed for the metal-phosphorus bonds,
AC C
which are in the range of 2.2759(9) Å - 2.2895(10) Å for 2, and between 2.2514(13) Å 2.2596(13) Å for the platinum complex.
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
Figure 3: Solid-state structure of [(GemPhos)(PdCl2)] (2) (left) and [(GemPhos)(PtCl2)] (3) (right). Hydrogen atoms are omitted for clarity. Selected bond lengths [Å] and angles [°] for 2
TE D
and the isostructural platinum complex 3: 2: Pd-Cl1 2.3546(10), Pd-Cl2 2.3449(10), Pd-P1 2.2759(9), Pd-P2 2.2895(10), P1-C1 1.829(4), P1-C7 1.827(4), P1-C13 1.838(3), P1-P2 3.5192(2); Cl1-Pd-Cl2 87.37(4), Cl1-Pd-P1 83.56(4), Cl2-Pd-P2 88.09(3), P1-Pd-P2
EP
100.86(3), Cl1-Pd-P2 175.37(4), Cl2-Pd-P1 168.92(4), Pd-P1-C1 105.45(12); Pd-P1-C7 114.54(12), Pd-P1-C13 124.69(11), C1-P1-C7 108.9(2), C1-P1-C13 100.8(2), C7-P1-C13
AC C
101.1(2); 3: Pt-Cl1 2.3452(14), Pt-Cl2 2.3590(13), Pt-P1 2.2596(13), Pt-P2 2.2514(13), P1C1 1.836(5), P1-C7 1.831(5), P1-C13 1.830(5), P1-P2 3.4898(1); Cl1-Pt-Cl2 85.75(5), Cl1Pt-P1 88.56(4), Cl2-Pt-P2 84.25(5), P1-Pt-P2 101.36(5), Cl1-Pt-P2 168.42(5), Cl2-Pt-P1 174.28(5), Pt-P1-C1 114.9(2); Pt-P1-C7 109.5(2), Pt-P1-C13 121.1(2), C1-P1-C7 104.4(2), C1-P1-C13 102.4(2), C7-P1-C13 102.5(2). These bond lengths are in accordance with comparable compounds that have been reported in the literature ([(dppm)(PdCl2)]: av. bond lengths Pd-Cl = 2.357 Å, Pd-P = 2.238 Å [54]; [(XantPhos)(PdCl2)]: av. bond lengths Pd-Cl 2.3473 Å, Pd-P 2.2836 Å) [55]; [(dppm)(PtCl2)]:
ACCEPTED MANUSCRIPT av. bond lengths Pt-Cl = 2.358 Å, Pt-P = 2.212 Å [56]; [(XantPhos)(PtCl2)]: av. bond lengths Pt-Cl 2.351 Å, Pt-P 2.259 Å [57]). The metal atoms exhibit square-planar coordination geometry, which is very typical for d8-complexes. The Cl-M-Cl angles for both the palladium (Cl1-Pd-Cl2 87.37(4)°) and the platinum compound (Cl1-Pt-Cl2 85.75(6)°) differ slightly
RI PT
from the ideal angle (90°). The P1-M-P2 angles are elongated to 100.86(3)° (2) and 101.36(5)° (3). As a result, the bite angle is significantly smaller compared to the gold complex 1, but very similar to the known compounds [(XantPhos)(MCl2)] (P1-Pd-P2
SC
100.61(5)° [55] and P1-Pt-P2 100.87(8)° [57]). The intramolecular P1-P2 distances are remarkably shortened to 3.5192(2) Å (2) and 3.4898(1) Å (3) compared with the free ligand (-
M AN U
0.5 Å), [GemPhos(AuCl)2] (-1 Å) and 1 (- 0.5 Å). This is caused by the square-planar coordination sphere of the metals, in which the phosphine atoms are forced into closer
TE D
proximity.
Photophysical properties:
Since complexes 1-3 are very poorly soluble in common organic solvents, characterization of
EP
their PL properties has been focused on solid (polycrystalline) samples. In all complexes, the
AC C
PL excitation (PLE) spectra correspond to the intense absorption of the GemPhos ligand below ~400 nm (Figures 4, 5). The PLE spectra also resemble those of the dinuclear gold complexes with PhanePhos and GemPhos ligands [43]. The emission properties of 1-3 were found to be strongly dependent on the metal. Gold complex 1 shows a green emission band at ~530 nm at room temperature, which intensity strongly increases and maximum shifts to ~515 nm by decreasing the temperature down to 18 K (Figure 4). The emission decays on the time scale of a few milliseconds/ a few microseconds at 18/ 295 K, respectively, thus correlating with the temperature dependence of the PL intensity. The above properties of 1 are quite similar to those of the dinuclear gold complexes with PhanePhos and GemPhos ligands,
ACCEPTED MANUSCRIPT which demonstrate bright low-temperature phosphorescence at 500 and 485 nm, respectively [43]. Bright visible phosphorescence of gold complexes has typically been associated with ligand- and metal-involving charge-transfer excited states, usually of ligand-to-metal chargetransfer character [11, 13]. Interestingly, according to comprehensive theoretical
RI PT
investigations, the phosphorescence of the PhanePhos dinuclear gold complex originates from the metal-to-ligand charge-transfer (MLCT) state [47]. In contrast, an emitting triplet state of the ligand-localized character has been predicted for the dinuclear gold complex with
SC
GemPhos ligand (demonstrating no aurophilic interaction) [47]. The gold atoms in the latter complex may provide an effective spin interconversion between the ligand states. The
M AN U
emission of 1 is comparatively red shifted, correspondingly, it might be similar to that of the PhanePhos dinuclear gold complex. The exact nature of the emissive state of 1 is, however,
AC C
EP
TE D
not clear at the moment.
Figure 4: Photoluminescence excitation (PLE) and emission (PL) spectra of gold complex 1 in the solid state at different temperatures.
The platinum complex 3 shows very weak fluorescence at ~420 nm at room temperature, which significantly increases in intensity after cooling the complex below ~100 K (Figure 5).
ACCEPTED MANUSCRIPT The fluorescence can be assigned to the GemPhos ligand. Its spectrum and temperature dependence also correspond well to those of the solid PhanePhos ligand [47]. Note that in 1, the ligand fluorescence is likely masked by the relatively strong green PL. No other, lowerenergy emission (involving Pt excited states) was detected for 3. This is not surprising, since
RI PT
Pt complexes with simple inorganic ligands like chlorides are typically non-emissive because of the very efficient non-radiative relaxation to the ground state [12]. The ligand-based fluorescence of palladium complex 2 is similar to that of 3, but is much weaker, also at
SC
cryogenic temperatures. Instead, below ~100 K, complex 2 shows moderately intense nearinfrared PL at ~800 nm (Figure 5). It decays with a time constant of 50 µsec at T = 18 K.
M AN U
Such phosphorescence has been observed for other Pd complexes and may be assigned to a palladium-centered 3d-d excited state [58].
AC C
EP
TE D
.
Figure 5: Photoluminescence excitation (PLE) and emission (PL) spectra of Pd complex 2 and Pt complex 3 in the solid state at 18 K. The spectra were excited at 350 nm and recorded at 800 and 440 nm, respectively, and are shown vertically shifted for clarity.
ACCEPTED MANUSCRIPT Conclusion The GemPhos ligand was successfully applied as a ligand for complexation of the noble metals gold, palladium and platinum. The reaction with [Au(tht)2][ClO4] did not result in a
RI PT
homoleptic dinuclear gold complex. Instead, a mononuclear charge-separated compound was obtained, in which the gold atom exhibits an unusual trigonal planar coordination geometry. The palladium and platinum complexes were obtained in very good yields by reaction of the diphosphine ligand with the commercially available metal precursors [MCl2(COD)] in hot
SC
DMSO. All compounds were fully characterized by analytical and spectroscopic techniques
M AN U
and their solid-state structures were established by single crystal X-ray crystallography. The photoluminescent properties were measured at low and ambient temperature revealing different emission patterns, depending on the metal and the coordination mode. For instance, the palladium complex 2 shows near-infrared phosphorescence at temperatures below ~100 K, which was attributed to the metal-centered triplet excited state. No related emission was
TE D
detected for the platinum complex 3. In contrast, the gold complex 1 features a green emission at ~520 nm, which is particularly bright at low temperatures and is similar to that of the
EP
dinuclear GemPhos and PhanePhos gold complexes [47]. Additionally, the obtained compounds appear to be interesting as potential catalysts in cross-coupling or hydrogenation
AC C
reactions.
Experimental
General procedures: All manipulations were performed in Schlenk-type glassware or in an argon-filled MBraun glovebox. Furthermore, gold compounds were handled under the exclusion of light by wrapping the compound-containing flasks in aluminum foil. Visible decomposition (a pink coloration) is observed after a few days for the gold complex (Au
ACCEPTED MANUSCRIPT reduction) although the obtained products can be handled in air and with technical-grade solvents. Prior to use, CH2Cl2 was distilled under nitrogen from CaH2. THF, diethyl ether, and n-pentane were dried using an MBraun solvent purification system (SPS-800). Deuterated solvents were obtained from Carl Roth GmbH (99.5 atom % D). NMR spectra were recorded
residual 1H and
13
RI PT
on a BrukerAvance II 300 MHz or Avance 400 MHz. Chemical shifts are referenced to the C resonances of the deuterated solvents and are reported relative to
tetramethylsilane and 85% phosphoric acid (31P NMR) respectively. IR spectra were
SC
measured on a Bruker Tensor 37. EI-Mass spectra were recorded at 70 eV on a Thermo Scientific DFS. ESI mass spectra were obtained using a FT-ICR (Fourier transform ion
M AN U
cyclotron resonance) IonSpec Ultima mass spectrometer equipped with a 7T magnet (Cryomagnetics). Elemental analyses were carried out with an ElementarVario EL or Micro Cube. [Au(tht)2][ClO4] [59] and GemPhos [46] were prepared according to literature procedures. [PdCl2(COD)] and [PtCl2(COD)] were purchased from Alfa-Aesar and used as
TE D
received.
EP
X-Ray Crystallographic Studies: A suitable crystal was covered in mineral oil (Aldrich) and mounted on a glass fibre. The crystal was transferred directly to the cold stream of a STOE
AC C
IPDS 2. All structures were solved by direct methods or by the Patterson method (SHELXS2013) [60]. The remaining non-hydrogen atoms were located from difference in Fourier map calculations. The refinements were carried out by using full-matrix least-squares techniques on F, minimizing the function (F0 - Fc)2, where the weight is defined as 4F02/2(F02) and F0 and Fc are the observed and calculated structure factor amplitudes using the program SHELXL-2013 [60]. Carbon-bound hydrogen atom positions were calculated. The locations of the largest peaks in the final difference Fourier map calculation, as well as the magnitude of the residual electron densities, in each case were of no chemical significance. Positional
ACCEPTED MANUSCRIPT parameters, hydrogen atom parameters thermal parameters, bond lengths and angles have been deposited as Supporting Information.
RI PT
Photophysical measurements: The PL measurements were performed on a Horiba JobinYvon Fluorolog-322 spectrometer equipped with a closed-cycle optical cryostat (Leybold) operating at ~18-300 K. Hamamatsu R9910 and R5509 photomultipliers were used
SC
as detectors for the emission spectral range of ~300-850 and ~450-1400 nm, respectively. Solid samples (crystalline powders) were measured as dispersions in a thin layer of
M AN U
polyfluoroester oil (ABCR GmbH) placed between two 1 mm quartz plates. All emission spectra were corrected for the wavelength-dependent response of the spectrometer and detector (in relative photon flux units). Emission decay traces were recorded by connecting a photomultiplier to an oscilloscope (typically via a 500 Ohm load) and using a N2–laser for
TE D
pulsed excitation at 337 nm (~2 ns, ~5 µJ per pulse).
EP
[(GemPhos)Au(tht)]ClO4 (1)
[Au(tht)2][ClO4] (118 mg, 0.25 mmol) was dissolved in dichloromethane (10 mL). With
AC C
stirring, GemPhos (144 mg, 0.25 mmol) was added and the resulting mixture was stirred for one hour. After removal of the solvent, the residue was washed with diethyl ether (2 x 5 mL) and the remaining solid was finally dried under high vacuum to obtain the product as a colourless solid. Yield: 183 mg (85 %). Single crystals suitable for X-ray crystallography were obtained by slow diffusion of n-pentane into a solution of 1 in dichloromethane. 1H NMR (300.13 MHz, CD2Cl2): δ (ppm) = 7.65-7.40 (m, 20H, Ph), 6.87 (dd, 3JHH = 7.6 Hz, 4
JHH = 1.5 Hz, 2H, HPC), 6.79 (dt, 3JHH = 7.6 Hz, 4JPH = 2.8 Hz, 2H, HPC), 5.97 (dt, 3JPH = 7.1
Hz, 4JHH = 1.7 Hz, 2H, HPC), 3.40-3.33 (m, 4H, CH2S), 3.26 (dd, 3JHH = 13.8 Hz, 4JHH = 3.8
ACCEPTED MANUSCRIPT Hz, 2H, CH2), 3.08 (dd, 3JHH = 13.0 Hz, 4JHH = 4.3 Hz, 2H, CH2), 2.94 (dd, 3JHH = 13.6 Hz, 4
JHH = 3.6 Hz, 2H, CH2), 2.74 (dd, 3JHH = 13.1 Hz, 4JHH = 4.3 Hz, 2H, CH2), 2.18-2.09 (m,
4H, CH2CH2S).
13
C{1H} NMR (75.48 MHz, CD2Cl2): δ (ppm) = 142.7 (t, JCP = 5.5 Hz),
141.3 (t, JCP = 4.4 Hz), 136.8 (t, JCP = 4.0 Hz), 136.3 (t, JCP = 1.1 Hz), 135.1 (t, JCP = 8.6 Hz),
RI PT
133.7 (t, JCP = 26.2 Hz), 133.6 (t, JCP = 3.2 Hz), 133.4 (t, JCP = 9.2 Hz), 132.6 (m), 132.3 (m), 131.8 (t, JCP = 23.9 Hz), 130.2 (t, JCP = 5.6 Hz), 129.9 (t, JCP = 5.9 Hz), 128.8 (t, JCP = 22.5 Hz), 40.2 (s, CH2S), 35.2 (t, JCP = 4.8Hz, CH2), 35.0 (s, CH2), 31.5 (s, CH2CH2S).
31
P{1H}
SC
NMR (121.48 MHz, CD2Cl2): δ (ppm) = 42.7. IR (ATR): ν ̃ (cm-1) = 3056 (w), 2961 (w), 1617 (w), 1559 (w), 1541 (w), 1457 (m), 1260 (m), 1182 (w), 1163 (w), 1086 (vs), 1023 (s),
M AN U
915 (w), 870 (w), 798 (s), 749 (m), 693 (s), 622 (s), 551 (m), 508 (vs). – Raman (solid state): ν ̃ (cm-1) = 3060 (s), 2934 (m), 1585 (s), 1185 (m), 1096 (w), 1027 (m), 1000 (s), 932 (m), 695 (w), 677 (w), 618 (w), 464 (w), 331 (w), 261 (w). ESI-MS (DCM): m/z = 773.21 ([(GemPhos)Au]+),
257.74
([(GemPhos)Au]3+).
Elemental
analysis
calcd
(%)
for
EP
[(GemPhos)(PdCl2)] (2)
TE D
C44H42AuClO4P2S (961.23): C 54.98, H 4.40, S 3.34; found C 54.50, H 4.67, S 3.14.
AC C
[PdCl2(COD)] (54.5 mg, 0.19 mmol) was dissolved in DMSO (3 mL). With stirring, GemPhos (110 mg, 0.19 mmol) was added and the red solution was heated to 100°C and stirred for one hour. After cooling to room temperature, the product precipitates as yellow crystals, which were collected and dried under vacuum. Yield: 120 mg (84 %). 1H NMR (300.13 MHz, DMSO-d6): δ (ppm) = 8.24 (dd, 3JHH = 11.7 Hz, 7.2 Hz, 4H, Ph), 8.05-7.95 (m, 4H, Ph), 7.63-7.50 (m, 12H, Ph), 6.80 (d, 3JHH = 7.7 Hz, 2H, Ph), 6.44 (dd, 3JHH = 7.6 Hz, 5.0 Hz, 2H, Ph), 5.92 (d, 3JPH = 14.3 Hz, 2H, Ph), 2.90 (d, 3JHH = 7.8 Hz, 2H, CH2), 2.65 (d, 3JHH = 7.5 Hz, 2H, CH2), 2.12-2.07 (m, 4H, CH2). – resonances could be detected.
31
13
C{1H} NMR: Due to low solubility no
P{1H} NMR (121.48 MHz, DMSO-d6): δ (ppm) = 37.8. IR
ACCEPTED MANUSCRIPT (ATR): ν ̃ (cm-1) = 3056 (w), 2935 (w), 2860 (w), 1571 (w), 1480 (m), 1434 (s), 1399 (m), 1313 (w), 1262 (w), 1185 (m), 1158 (w), 1113 (w), 1089 (s), 1058 (w), 1027 (w), 998 (w), 956 (w), 916 (m), 874 (w), 843 (m), 802 (m), 761 (s), 745 (s), 720 (w), 694 (vs), 620 (w), 601 (w), 553 (s), 524 (vs), 511 (s). Raman (solid state): ν ̃ (cm-1) = 3079 (w), 3060 (s), 3003 (w),
RI PT
2957 (m), 2911 (m), 2861 (m), 1586 (s), 1551 (w), 1466 (w), 1439 (w), 1191 (m), 1160 (w), 1091 (w), 1065 (w), 1032 (m), 1003 (vs), 917 (w), 875 (w), 842 (w), 821 (w), 691 (w), 679 (w), 619 (w), 603 (w), 493 (w), 475 (w), 309 (vs), 294 (m), 261 (w), 251 (w), 233 (w), 192
SC
(vs), 164 (s). Elemental analysis calcd (%) for C40H34Cl2P2Pd (753.98): C 62.72, H 4.55;
M AN U
found C 62.39, H 4.80.
[(GemPhos)(PtCl2)] (3)
Synthesis as described for 2, using [PtCl2(COD)] (71 mg, 0.19 mmol) and GemPhos (110 mg,
TE D
0.19 mmol), to obtain the product as colourless crystals. Yield: 130 mg (81 %). 1H NMR (300.13 MHz, DMSO-d6): δ (ppm) = 8.24-8.14 (m, 4H, Ph), 8.06-7.97 (m, 4H, Ph), 7.61-7.50 (m, 12H, Ph), 6.70 (d, 3JHH = 8.0 Hz, 2H, Ph), 6.46 (dd, 3JHH = 7.8 Hz, 4.6 Hz, 2H, Ph), 6.07
EP
(d, 3JPH = 12.3 Hz, 2H, Ph), 2.94-2.86 (m, 2H, CH2), 2.74-2.68 (m, 2H, CH2), 2.30-2.24 (m, 2H, CH2), 2.15-2.08 (m, 2H, CH2). 13C{1H} NMR: Due to low solubility, no resonances could
Hz).
AC C
be detected. 31P{1H} NMR (121.49 MHz, DMSO-d6): δ (ppm) = 15.9 (s), 15.9 (d, 1JPtP = 3656 195
Pt NMR (86.02 MHz, DMSO-d6): δ (ppm) = -4575 (t, 1JPtP = 3656 Hz). IR (ATR): ν ̃
(cm-1) = 3053 (w), 2934 (w), 2860 (w),1572 (w), 1480 (m),1435 (s), 1399 (m), 1312 (w), 1184 (m), 1157 (w), 1115 (w), 1090 (s), 1058 (w), 1028 (w), 999 (w), 956 (w), 917 (m), 875 (w), 844 (m), 820 (w), 761 (s), 746 (s), 722 (w), 694 (vs), 620 (w), 603 (w), 554 (m), 541 (vs), 527 (s), 515 (w). Raman (solid state): ν ̃(cm-1) = 3167 (w), 3140 (w), 3081 (w), 3061 (s), 3003 (w), 2957 (m), 2860 (w), 1587 (s), 1463 (w), 1441 (w), 1194 (m), 1160 (w), 1093 (w), 1029 (m), 1003 (vs), 916 (w), 843 (w), 822 (w), 699 (w), 680 (w), 619 (w), 604 (w), 477 (w), 315
ACCEPTED MANUSCRIPT (s), 295 (m), 263 (w), 236 (w), 192 (s), 174 (s). Elemental analysis calcd (%) for C40H34Cl2P2Pt (842.65): C 57.02, H 4.07; found C 56.32; H 4.32.
RI PT
Crystal data for 1: C44H42AuP2S•ClO4•2(CH2Cl2), M = 1131.04, a = 9.123(2) Å, b = 21.903(4) Å, c = 23.052(5) Å, V = 4606.1(16) Å3, T = 200 K, space group P212121, Z = 4, 33541 reflections measured, 8558 independent reflections (Rint = 0.0785). The final R1 values
SC
were 0.0362 (I > 2σ(I)). The final wR(F2) values were 0.0624 (I > 2σ(I)). The final R1 values were 0.0495 (all data). The final wR(F2) values were 0.0651 (all data).
M AN U
Crystal data for 2: C40H34Cl2P2Pd, M = 753.91, a = 9.5468(8) Å, b = 19.6694(9) Å, c = 17.9286(4) Å, β = 100.226(4)°, V = 3313.2(3) Å3, T = 200 K, space group P21/c, Z = 4, 27007 reflections measured, 6180 independent reflections (Rint = 0.0577). The final R1 values were 0.0393 (I > 2σ(I)). The final wR(F2) values were 0.0756 (I > 2σ(I)). The final R1 values were
TE D
0.0674 (all data). The final wR(F2) values were 0.0824 (all data).
Crystal data for 3: C40H34Cl2P2Pt, M = 842.60, a = 9.5263(3) Å, b = 19.6187(4) Å, c =
EP
17.8612(5) Å, β = 100.372(2)°, V = 3283.60(16) Å3, T = 150 K, space group P21/c, Z = 4, 30396 reflections measured, 6476 independent reflections (Rint = 0.0751). The final R1 values
AC C
were 0.0327 (I > 2σ(I)). The final wR(F2) values were 0.0544 (I > 2σ(I)). The final R1 values were 0.0609 (all data). The final wR(F2) values were 0.0608 (all data).
Crystallographic data (excluding structure factors) for the structures reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as a supplementary publication no. CCDC-1039016 (1), 1039016 (2), and 1039018 (3). Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, UK (fax: (+(44)1223-336-033; email: [email protected]).
ACCEPTED MANUSCRIPT
Acknowledgements Financial support by the DFG-funded transregional collaborative research centre SFB/TRR 88
RI PT
“Cooperative Effects in Homo- and Heterometallic Complexes (3MET)” is gratefully acknowledged (projects C3 and C7). C.S. gratefully acknowledges the Konrad Adenauer Stiftung for a generous fellowship. S.B. thanks the Studienstiftung des Deutschen Volkes and
SC
the Fonds der Chemischen Industrie (FCI) for generous fellowships.
M AN U
Keywords: gold, luminescence, palladium, paracyclophane, platinum, phosphine
References
J.M. Brunel, Chem. Rev., 105 (2005) 857.
[2]
J.H. Downing and M.B. Smith, in J.A.M.J. Meyer (Editor), Comprehensive
TE D
[1]
Coordination Chemistry II, Pergamon, Oxford, 2003, p. 253. F. Mathey, Chem. Rev., 88 (1988) 429.
[4]
L.D. Quin, A Guide to Organophosphorus Chemistry, John Wiley & Sons, New York,
[5]
AC C
2000.
EP
[3]
P.C.J. Kamer and P.W.N.M.v. Leeuwen (Editors), Phosphorus(III)Ligands in
Homogeneous Catalysis: Design and Synthesis, Wiley, New York, 2012. [6] [7]
M. Schlosser, Organometallics in Synthesis, John Wiley & Sons, Inc., 2013, p. 1. J.-L. Malleron, J.-C. Fiaud and J.-Y. Legros, in J.-L.M.-C.F.-Y. Legros (Editor),
Handbook of Palladium-Catalyzed Organic Reactions, Academic Press, London, 1997. [8]
Á. Molnár (Editor), Palladium-Catalyzed Coupling Reactions: Practical Aspects and
Future Developments, Wiley-VCH Verlag GmbH & Co. KGaA, 2013.
ACCEPTED MANUSCRIPT [9]
M. Muro, A. Rachford, X. Wang and F. Castellano, in A.J. Lees (Editor),
Photophysics of Organometallics, Vol. 29, Springer Berlin Heidelberg, 2010, p. 1. [10]
C. Reber, J.K. Grey, E. Lanthier and K.A. Frantzen, Comments on Inorganic
Chemistry, 26 (2005) 233. E.R.T. Tiekink and J.-G. Kang, Coord. Chem. Rev., 253 (2009) 1627.
[12]
J.A.G. Williams, in V. Balzani and S. Campagna (Editors), Photochemistry and
RI PT
[11]
Photophysics of Coordination Compounds II, Vol. 281, Springer Berlin Heidelberg, 2007, p.
SC
205.
V.W.-W. Yam and E.C.-C. Cheng, Chem. Soc. Rev., 37 (2008) 1806.
[14]
Á. Díez, E. Lalinde and M.T. Moreno, Coord. Chem. Rev., 256 (2011) 2426.
[15]
Chi-Hang Tao and V.W.-W. Yam, J. Photochem. and Photobiol. C: Photochem. Rev.,
M AN U
[13]
10 (2009) 130.
G.J. Hutchings, M. Brust and H. Schmidbaur, Chem. Soc. Rev., 37 (2008) 1759.
[17]
A.S.K. Hashmi, Nach. Chem., 57 (2009) 379.
[18]
A.S.K. Hashmi and G.J. Hutchings, Angew. Chem., Int. Ed., 45 (2006) 7896.
[19]
A.S.K. Hashmi and M. Rudolph, Chem. Soc. Rev., 37 (2008) 1766.
[20]
M. Chen and D.W. Goodman, Chem. Soc. Rev., 37 (2008) 1860.
[21]
R. Coquet, K.L. Howard and D.J. Willock, Chem. Soc. Rev., 37 (2008) 2046.
[22]
A. Corma and H. Garcia, Chem. Soc. Rev., 37 (2008) 2096.
[24]
EP
AC C
[23]
TE D
[16]
C. Della Pina, E. Falletta, L. Prati and M. Rossi, Chem. Soc. Rev., 37 (2008) 2077. J.C. Fierro-Gonzalez and B.C. Gates, Chem. Soc. Rev., 37 (2008) 2127.
[25]
M.C. Gimeno and A. Laguna, Chem. Soc. Rev., 37 (2008) 1952.
[26]
M. Grzelczak, J. Perez-Juste, P. Mulvaney and L.M. Liz-Marzan, Chem. Soc. Rev., 37
(2008) 1783. [27]
H. Hakkinen, Chem. Soc. Rev., 37 (2008) 1847.
[28]
M. Jansen, Chem. Soc. Rev., 37 (2008) 1826.
ACCEPTED MANUSCRIPT [29]
M.J. Katz, K. Sakai and D.B. Leznoff, Chem. Soc. Rev., 37 (2008) 1884.
[30]
T. Laaksonen, V. Ruiz, P. Liljeroth and B.M. Quinn, Chem. Soc. Rev., 37 (2008)
1836. N. Marion and S.P. Nolan, Chem. Soc. Rev., 37 (2008) 1776.
[32]
V. Myroshnychenko, J. Rodriguez-Fernandez, I. Pastoriza-Santos, A.M. Funston, C.
RI PT
[31]
Novo, P. Mulvaney, L.M. Liz-Marzan and F.J. Garcia de Abajo, Chem. Soc. Rev., 37 (2008) 1792.
Y. Ofir, B. Samanta and V.M. Rotello, Chem. Soc. Rev., 37 (2008) 1814.
[34]
B.L.V. Prasad, C.M. Sorensen and K.J. Klabunde, Chem. Soc. Rev., 37 (2008) 1871.
[35]
R.J. Puddephatt, Chem. Soc. Rev., 37 (2008) 2012.
[36]
P. Pyykkö, Chem. Soc. Rev., 37 (2008) 1967.
[37]
H.G. Raubenheimer and S. Cronje, Chem. Soc. Rev., 37 (2008) 1998.
[38]
G. Schmid, Chem. Soc. Rev., 37 (2008) 1909.
[39]
H. Schmidbaur and A. Schier, Chem. Soc. Rev., 37 (2008) 1931.
[40]
R.A. Sperling, P. Rivera Gil, F. Zhang, M. Zanella and W.J. Parak, Chem. Soc. Rev.,
37 (2008) 1896.
TE D
M AN U
SC
[33]
R. Wilson, Chem. Soc. Rev., 37 (2008) 2028.
[42]
H. Schmidbaur and A. Schier, Z. Naturforsch., B J. Chem. Sci., 66 (2011) 329.
[43]
H. Schmidbaur and A. Schier, Chem. Soc. Rev., 41 (2012) 370.
[45]
AC C
[44]
EP
[41]
A. Arcadi, Chem. Rev., 108 (2008) 3266. P.J. Pye, K. Rossen, R.A. Reamer, N.N. Tsou, R.P. Volante and P.J. Reider, J. Am.
Chem. Soc., 119 (1997) 6207. [46]
F.C. Falk, R. Fröhlich and J. Paradies, Chemical Communications, 47 (2011) 11095.
[47]
C. Sarcher, A. Lühl, F.C. Falk, S. Lebedkin, M. Kuhn, C. Wang, J. Paradies, M.M.
Kappes, W. Klopper and P.W. Roesky, Eur J Inorg Chem, (2012) 5033.
ACCEPTED MANUSCRIPT [48]
J.M. Serrano-Becerra, A.F.G. Maier, S. Gonzalez-Gallardo, E. Moos, C. Kaub, M.
Gaffga, G. Niedner-Schatteburg, P.W. Roesky, F. Breher and J. Paradies, Eur J Org Chem, (2014) 4515. J.A. Muir, M.M. Muir and S. Arias, Acta Cryst. Sect. B, 38 (1982) 1318.
[50]
J. Meiners, J.-S. Herrmann and P.W. Roesky, Inorg. Chem., 46 (2007) 4599.
[51]
Z. Assefa, R.J. Staples and J.P. Fackler, Inorg. Chem., 33 (1994) 2790.
[52]
K. Ortner, L. Hilditch, Y. Zheng, J.R. Dilworth and U. Abram, Inorg. Chem., 39
RI PT
[49]
[53]
SC
(2000) 2801.
F.C. Falk, P. Oechsle, W.R. Thiel, C.G. Daniliuc and J. Paradies, Eur J Org Chem,
M AN U
2014 (2014) 3637. [54]
W.L. Steffen and G.J. Palenik, Inorg. Chem., 15 (1976) 2432.
[55]
A.M. Johns, M. Utsunomiya, C.D. Incarvito and J.F. Hartwig, J. Am. Chem. Soc., 128
(2006) 1828.
A. Babai, G.B. Deacon, A.P. Erven and G. Meyer, Z. Anorg. Allg. Chem, 632 (2006)
639. [57]
T. Niksch, H. Görls, M. Friedrich, R. Oilunkaniemi, R. Laitinen and W. Weigand, Eur
EP
J Inorg Chem, (2010) 74. [58]
TE D
[56]
B.-C. Tzeng, S.-C. Chan, M.C.W. Chan, C.-M. Che, K.-K. Cheung and S.-M. Peng,
[59]
AC C
Inorg. Chem., 40 (2001) 6699. R. Usón, A. Laguna, A. Navarro, R.V. Parish and L.S. Moore, Inorg. Chim. Acta, 112
(1986) 205. [60]
G. Sheldrick, Acta Cryst. Sect. A, 64 (2008) 112.
ACCEPTED MANUSCRIPT TOC GemPhos, a diphosphine ligand with a rigid paracyclophane scaffold, was used to prepare
AC C
EP
TE D
M AN U
SC
RI PT
complexes of the noble metals gold, palladium and platinum.
ACCEPTED MANUSCRIPT Highlights
RI PT SC M AN U TE D
•
EP
•
A rigid paracyclophane scaffold, was used to prepare complexes of the noble metals gold, palladium and platinum. In the gold complex the metal atom exhibits an uncommon trigonal planar coordination geometry. The photoluminescent properties of all complexes were determined at low and ambient temperatures.
AC C
•
S0022-328X(15)00111-4
DOI:
10.1016/j.jorganchem.2015.02.033
Reference:
JOM 18934
To appear in:
Journal of Organometallic Chemistry
Received Date: 18 December 2014 Revised Date:
20 February 2015
Accepted Date: 21 February 2015
Please cite this article as: C. Sarcher, S. Bestgen, F.C. Falk, S. Lebedkin, J. Paradies, P.W. Roesky, Synthesis and Photophysical Properties of GemPhos Noble Metal Complexes, Journal of Organometallic Chemistry (2015), doi: 10.1016/j.jorganchem.2015.02.033. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
AC C
EP
TE D
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
ACCEPTED MANUSCRIPT
Synthesis and Photophysical Properties of GemPhos Noble Metal Complexes Christian Sarcher,[a] Sebastian Bestgen,[a] Florian C. Falk,[c] Sergei Lebedkin,*[b] Jan
RI PT
Paradies,[c,d] and Peter W. Roesky[a]*
[a] Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstraße
SC
15, 76131 Karlsruhe (Germany), Fax: (+)49 721 6084 4854, E-mail: [email protected]
M AN U
[b] Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber Weg 2, 76131 Karlsruhe (Germany) and Institut für Nanotechnologie Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76021 Karlsruhe (Germany).
TE D
[c] Institute of Organic Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany).
EP
[d] Institut für Organische Chemie, Universität Paderborn, Warburger Str. 100, 33098
AC C
Paderborn (Germany).
ACCEPTED MANUSCRIPT Abstract GemPhos, a diphosphine ligand with a rigid paracyclophane scaffold, was used to prepare complexes of the noble metals gold, palladium, and platinum. The reaction of GemPhos with
RI PT
[Au(tht)2][ClO4] (tht = tetrahydrothiophene) surprisingly yielded a mononuclear charge separated gold compound [(GemPhos)Au][ClO4], in which the gold atom exhibits an uncommon trigonal planar coordination geometry. Furthermore, similar palladium [(GemPhos)(PdCl2)] and platinum [(GemPhos)(PtCl2)] complexes were obtained in very good
SC
yields by the reaction of GemPhos with [MCl2(COD)] (M = Pd, Pt; COD = 1,5-
M AN U
cyclooctadiene) in hot DMSO. All compounds were fully characterized by analytical and spectroscopic techniques and their solid-state structures were established by single X-ray crystallography. Their photoluminescent properties were measured at low and ambient
AC C
EP
TE D
temperatures, revealing different behavior depending on the metal and coordination mode.
ACCEPTED MANUSCRIPT Introduction Bidentate ligands with phosphorus donor atoms are well-established in organometallic chemistry [1-4]. In combination with noble metals they are widely used, for instance, in
RI PT
homogeneous catalysis [5]. By changing the phosphorus' substitutes, the electronic and steric properties of the ligand can be modified, which affects the bite angle and coordination behavior in metal complexes. Especially in homogeneous catalysis, the selectivity and reaction rates can be explicitly diversified. Also the solubility of the catalyst depends on the
SC
properties of the phosphine ligand. The noble metals gold, palladium and platinum are of
M AN U
particular interest with respect to hetero- and homogeneous catalysis [6-8], as well as their photoluminescent (PL) properties [9-15]. Nowadays, the synthesis and application of gold compounds is one of the rapidly progressing fields in organometallic chemistry, as evidenced by the strongly increasing number of publications dealing with various gold-containing substances. This is mirrored by a significant number of reviews dealing with various topics of
TE D
gold chemistry [13, 16-44]. The emerging interest is caused by the unique properties that gold compounds exhibit, i.e. they are catalytically active in various organic transformations [42, 44] and show a phenomenon that is described as aurophilicity [39, 43]. This closed shell d10-
EP
d10 dispersion interaction is yet not fully understood, notably with respect to the influence of
AC C
such metal-metal interactions on the photophysical and catalytic properties. Additionally, palladium
and
platinum
compounds
are
widely
used
in
cross-coupling
or
hydrogenation/hydroformylation reactions [6-8], which find many applications in synthetic chemistry and industrial processes. Since we are interested in the photoluminescent behavior of metal complexes, dinuclear gold compounds of the very similar ligands PhanePhos [45] and GemPhos [46] have been examined. Quantum chemical and spectroscopic investigations revealed that the excited states of both compounds are highly influenced by the intramolecular gold distances [47]. However, their computed excitation energies, and consequently the absorption/ photoluminescence spectra, were quite similar. In this contribution we report three
ACCEPTED MANUSCRIPT new complexes of palladium, platinum and gold which were analyzed by analytical and spectroscopic techniques including photoluminescence (PL) spectroscopy. This work
RI PT
continues our studies on diphosphine ligands with a rigid paracyclophane scaffold.
Results and Discussion
Recently, the influence of aurophilic interactions on the catalytic and photophysical properties
complexes
[PhanePhos(AuCl)2]
and
SC
of dinuclear gold compounds has been investigated by us on two structurally very similar [GemPhos(AuCl)2]
(Scheme
1)
[47].
M AN U
[PhanePhos(AuCl)2] and [GemPhos(AuCl)2] coincide in their molecular formula and primarily differ in their intermetallic distances and thus allowed systematic studies with
EP
TE D
respect to hydroamination reactions and photoluminescent behavior [47].
compounds
without ([PhanePhos(AuCl)2]) and with
AC C
Scheme 1: Dinuclear gold,
([GemPhos(AuCl)2]) aurophilic interactions, respectively.
Since [GemPhos(AuCl)2] was successfully applied as a catalyst in the inter- and intramolecular hydroamination of alkynes and olefins [48] and exhibited bright-green phosphorescence in the solid state at low temperatures, we felt challenged to extend our studies on paracyclophane-based gold complexes and those of palladium and platinum. It is well-known that homoleptic gold phosphine complexes [P-Au-P] can be obtained by using
ACCEPTED MANUSCRIPT [Au(tht)2][ClO4] (tht = tetrahydrothiophene) as a starting material because the two labile tht ligands can be easily replaced by stronger σ-donors such as phosphines or NHCs. Surprisingly, the reaction of GemPhos and [Au(tht)2][ClO4] in a 1:1 ratio did not yield the expected dinuclear complex [(GemPhos)2Au2][ClO4]2. Instead, a heteroleptic gold(I)
RI PT
complex, [(GemPhos)Au(tht)][ClO4] (1), was isolated. In 1 the gold atom features a trigonal planar coordination environment (Scheme 2). Molecular gold(I) compounds with a closed shell d10 electronic configuration are linearly coordinated in most cases. However, gold(I)
SC
complexes possessing higher coordination numbers also exist, although they are less common
TE D
M AN U
[49-52].
Scheme 2: Synthesis of the heteroleptic complex [(GemPhos)Au(tht)][ClO4] (1).
EP
Complex 1 was fully characterized by analytical and spectroscopic techniques. The 1H NMR
AC C
spectrum is in accordance with the proposed structure, whereas the resonances for the ethylene units, as well as those for the tht ligand, are shifted slightly upfield compared to the starting materials. In the 31P{1H} NMR spectrum, a singlet is observed at 42.7 ppm, which is shifted considerably downfield (+ 50.4 ppm), compared to the free ligand GemPhos [46] and to [GemPhos(AuCl)2] (+ 13.4 ppm) [47] and thus indicating the coordination of the gold atom. As the complex is of ionic nature, ESI-MS was conducted to confirm the structure. An ion peak including the correct isotopic distribution is observed at m/z = 773.21 amu, which corresponds to the [(GemPhos)Au]+ fragment and further demonstrates the lability of the tht ligand in solution. The structure of 1 was unambiguously determined by single crystal X-ray
ACCEPTED MANUSCRIPT crystallography (Figure 1). The complex crystallizes in the orthorhombic space group P212121 with four molecules of 1 as well as eight molecules of dichloromethane in the unit cell. The Au-P distances slightly differ from each other with Au-P1 2.339(2) Å and Au-P2 2.342(2) Å, but they are in the expected range for Au-P bonds. The Au-S bond (2.428(2) Å) is elongated
RI PT
compared with [AuCl(tht)] (2.26 Å) indicating that the tht ligand is very weakly bound to the gold atom. The central atom itself exhibits an unusual trigonal planar coordination sphere. The gold atom and the donor atoms have an exact coplanar arrangement as shown by the
SC
angular sum of 359.99°. The P1-Au-P2 angle (115.99(7)°) is slightly more acute than the
AC C
EP
TE D
Au-S) and 121.44(9)° (P2-Au-S)).
M AN U
ideal angle of 120°. In contrast, the P-Au-S angles are somewhat widened (122.56(8)° (P1-
FIgure 1: Solid-state structure of [(GemPhos)(tht)Au][ClO4] (1). Hydrogen atoms and solvent molecules are omitted for clarity. Selected bond lengths [Å] and angles [°]: Au-S 2.427(2), Au-P1 2.339(2), Au-P2 2.342(2), P1-C1 1.838(8), P1-C13 1.833(8), P1-P2 3.9698(5); P1-Au-P2 115.99(7), P1-Au-S 122.55(8), P2-Au-S 121.45(9), Au-S-C41 112.7(4), Au-S-C44 109.6(4), Au-P1-C1 110.6(3), Au-P1-C7 118.3(3), Au-P1-C13 113.9(3), Au-P2C28 111.5(3), Au-P2-C29 114.5(3), Au-P2-C35 114.8(3), C1-P1-C7 104.4(4), C1-P1-C13
ACCEPTED MANUSCRIPT 105.0(4), P1-C13-C14 121.8(6), C13-C14-C15 122.0(8), C14-C15-C21 121.0(9), C15-C21C22 111.5(8), C21-C22-C26 114.7(8).
Compared with the trigonal planar coordinated gold complex [Au(PPh3)2(SCN)] [49] (P-Au-P
RI PT
127.8(1)°), the rigid backbone of the GemPhos ligand does not allow significant flexibility. The phosphine units are forced into close proximity upon gold coordination, as illustrated by the intramolecular P1-P2 distance of 3.9698(5) Å. This is considerably shorter than in
SC
[GemPhos(AuCl)2] [47] and even shorter than in the free ligand [46]. The observed
M AN U
coordination mode can be ascribed to the rigidity of the ligand. A weakly coordinating ligand is attached to the gold atom to complete the coordination sphere.
As a bidentate phosphine, GemPhos should be a suitable ligand for noble metals. Some of us have already reported the addition of [Pd(OAc)2] to GemPhos followed by oxidative addition
TE D
of chlorobenzene to the palladium atom [46]. Furthermore, the amidination of aryl chlorides by using the unsymmetrically substituted PhCy-GemPhos/Pd(OAc)2, which proved to be a highly active catalytic system, was investigated [53]. Since we were interested in
EP
photophysical properties, palladium and platinum complexes of the GemPhos ligand were prepared. As starting materials, the commercially available cyclooctadiene complexes
AC C
[MCl2(COD)] (M = Pd, Pt; COD = 1,5-cyclooctadiene) were chosen. Since all attempts to obtain the desired complexes by stirring a solution of metal precursor and phosphine ligand in dichloromethane failed, the reactions were conducted in DMSO at higher temperatures. Recrystallization of the crude products from hot DMSO resulted in the complexes [GemPhos(MCl2)] (Pd (2), Pt (3)) as single crystalline materials in very good yields (84% (2), 81% (3), Scheme 3).
RI PT
ACCEPTED MANUSCRIPT
SC
Scheme 3: Synthesis of [(GemPhos)(PdCl2)] (2) and [(GemPhos)(PtCl2)] (3).
Both compounds were fully characterized by analytical and spectroscopic techniques. Not
M AN U
surprisingly, the 1H NMR spectra of 2 and 3 are very similar. For the palladium complex, a sharp singlet is observed at 37.8 ppm in the 31P{1H} NMR spectrum, indicating the magnetic equivalency of the phosphorus atoms as well as metal complexation since the resonance is shifted significantly downfield (+30.1 ppm) as compared to the free ligand. The
31
P{1H}
TE D
NMR spectrum of 3 exhibits a singlet at 15.9 ppm flanked by platinum satellites with 1JPtP = 3656 Hz as the phosphines are coupled to the NMR-active isotope NMR and
31
195
Pt. Furthermore,
195
Pt
P{1H}/195Pt HMQC experiments were conducted to confirm the proposed
EP
structure. Because of the magnetic equivalency of both phosphorus atoms, a triplet at -4575 ppm is observed in
195
Pt NMR spectrum with the same coupling constant of 1JPtP = 3656 Hz.
AC C
The expected cross peaks can be found in the HMQC spectrum, further proving the direct PtP coupling (Figure 2).
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
TE D
Figure 2: 31P{1H}/195Pt HMQC NMR spectrum of 3 in DMSO-d6.
In the solid state, both compounds are isostructural and crystallize in the monoclinic space group P21/c with four molecules in the unit cell (Figures 3). The M-Cl distances are very
EP
similar for both complexes and vary between 2.3449(10) Å to 2.3546(10) Å (Pd-Cl) and 2.3452(14) Å to 2.3590(13) Å (Pt-Cl). The same is observed for the metal-phosphorus bonds,
AC C
which are in the range of 2.2759(9) Å - 2.2895(10) Å for 2, and between 2.2514(13) Å 2.2596(13) Å for the platinum complex.
M AN U
SC
RI PT
ACCEPTED MANUSCRIPT
Figure 3: Solid-state structure of [(GemPhos)(PdCl2)] (2) (left) and [(GemPhos)(PtCl2)] (3) (right). Hydrogen atoms are omitted for clarity. Selected bond lengths [Å] and angles [°] for 2
TE D
and the isostructural platinum complex 3: 2: Pd-Cl1 2.3546(10), Pd-Cl2 2.3449(10), Pd-P1 2.2759(9), Pd-P2 2.2895(10), P1-C1 1.829(4), P1-C7 1.827(4), P1-C13 1.838(3), P1-P2 3.5192(2); Cl1-Pd-Cl2 87.37(4), Cl1-Pd-P1 83.56(4), Cl2-Pd-P2 88.09(3), P1-Pd-P2
EP
100.86(3), Cl1-Pd-P2 175.37(4), Cl2-Pd-P1 168.92(4), Pd-P1-C1 105.45(12); Pd-P1-C7 114.54(12), Pd-P1-C13 124.69(11), C1-P1-C7 108.9(2), C1-P1-C13 100.8(2), C7-P1-C13
AC C
101.1(2); 3: Pt-Cl1 2.3452(14), Pt-Cl2 2.3590(13), Pt-P1 2.2596(13), Pt-P2 2.2514(13), P1C1 1.836(5), P1-C7 1.831(5), P1-C13 1.830(5), P1-P2 3.4898(1); Cl1-Pt-Cl2 85.75(5), Cl1Pt-P1 88.56(4), Cl2-Pt-P2 84.25(5), P1-Pt-P2 101.36(5), Cl1-Pt-P2 168.42(5), Cl2-Pt-P1 174.28(5), Pt-P1-C1 114.9(2); Pt-P1-C7 109.5(2), Pt-P1-C13 121.1(2), C1-P1-C7 104.4(2), C1-P1-C13 102.4(2), C7-P1-C13 102.5(2). These bond lengths are in accordance with comparable compounds that have been reported in the literature ([(dppm)(PdCl2)]: av. bond lengths Pd-Cl = 2.357 Å, Pd-P = 2.238 Å [54]; [(XantPhos)(PdCl2)]: av. bond lengths Pd-Cl 2.3473 Å, Pd-P 2.2836 Å) [55]; [(dppm)(PtCl2)]:
ACCEPTED MANUSCRIPT av. bond lengths Pt-Cl = 2.358 Å, Pt-P = 2.212 Å [56]; [(XantPhos)(PtCl2)]: av. bond lengths Pt-Cl 2.351 Å, Pt-P 2.259 Å [57]). The metal atoms exhibit square-planar coordination geometry, which is very typical for d8-complexes. The Cl-M-Cl angles for both the palladium (Cl1-Pd-Cl2 87.37(4)°) and the platinum compound (Cl1-Pt-Cl2 85.75(6)°) differ slightly
RI PT
from the ideal angle (90°). The P1-M-P2 angles are elongated to 100.86(3)° (2) and 101.36(5)° (3). As a result, the bite angle is significantly smaller compared to the gold complex 1, but very similar to the known compounds [(XantPhos)(MCl2)] (P1-Pd-P2
SC
100.61(5)° [55] and P1-Pt-P2 100.87(8)° [57]). The intramolecular P1-P2 distances are remarkably shortened to 3.5192(2) Å (2) and 3.4898(1) Å (3) compared with the free ligand (-
M AN U
0.5 Å), [GemPhos(AuCl)2] (-1 Å) and 1 (- 0.5 Å). This is caused by the square-planar coordination sphere of the metals, in which the phosphine atoms are forced into closer
TE D
proximity.
Photophysical properties:
Since complexes 1-3 are very poorly soluble in common organic solvents, characterization of
EP
their PL properties has been focused on solid (polycrystalline) samples. In all complexes, the
AC C
PL excitation (PLE) spectra correspond to the intense absorption of the GemPhos ligand below ~400 nm (Figures 4, 5). The PLE spectra also resemble those of the dinuclear gold complexes with PhanePhos and GemPhos ligands [43]. The emission properties of 1-3 were found to be strongly dependent on the metal. Gold complex 1 shows a green emission band at ~530 nm at room temperature, which intensity strongly increases and maximum shifts to ~515 nm by decreasing the temperature down to 18 K (Figure 4). The emission decays on the time scale of a few milliseconds/ a few microseconds at 18/ 295 K, respectively, thus correlating with the temperature dependence of the PL intensity. The above properties of 1 are quite similar to those of the dinuclear gold complexes with PhanePhos and GemPhos ligands,
ACCEPTED MANUSCRIPT which demonstrate bright low-temperature phosphorescence at 500 and 485 nm, respectively [43]. Bright visible phosphorescence of gold complexes has typically been associated with ligand- and metal-involving charge-transfer excited states, usually of ligand-to-metal chargetransfer character [11, 13]. Interestingly, according to comprehensive theoretical
RI PT
investigations, the phosphorescence of the PhanePhos dinuclear gold complex originates from the metal-to-ligand charge-transfer (MLCT) state [47]. In contrast, an emitting triplet state of the ligand-localized character has been predicted for the dinuclear gold complex with
SC
GemPhos ligand (demonstrating no aurophilic interaction) [47]. The gold atoms in the latter complex may provide an effective spin interconversion between the ligand states. The
M AN U
emission of 1 is comparatively red shifted, correspondingly, it might be similar to that of the PhanePhos dinuclear gold complex. The exact nature of the emissive state of 1 is, however,
AC C
EP
TE D
not clear at the moment.
Figure 4: Photoluminescence excitation (PLE) and emission (PL) spectra of gold complex 1 in the solid state at different temperatures.
The platinum complex 3 shows very weak fluorescence at ~420 nm at room temperature, which significantly increases in intensity after cooling the complex below ~100 K (Figure 5).
ACCEPTED MANUSCRIPT The fluorescence can be assigned to the GemPhos ligand. Its spectrum and temperature dependence also correspond well to those of the solid PhanePhos ligand [47]. Note that in 1, the ligand fluorescence is likely masked by the relatively strong green PL. No other, lowerenergy emission (involving Pt excited states) was detected for 3. This is not surprising, since
RI PT
Pt complexes with simple inorganic ligands like chlorides are typically non-emissive because of the very efficient non-radiative relaxation to the ground state [12]. The ligand-based fluorescence of palladium complex 2 is similar to that of 3, but is much weaker, also at
SC
cryogenic temperatures. Instead, below ~100 K, complex 2 shows moderately intense nearinfrared PL at ~800 nm (Figure 5). It decays with a time constant of 50 µsec at T = 18 K.
M AN U
Such phosphorescence has been observed for other Pd complexes and may be assigned to a palladium-centered 3d-d excited state [58].
AC C
EP
TE D
.
Figure 5: Photoluminescence excitation (PLE) and emission (PL) spectra of Pd complex 2 and Pt complex 3 in the solid state at 18 K. The spectra were excited at 350 nm and recorded at 800 and 440 nm, respectively, and are shown vertically shifted for clarity.
ACCEPTED MANUSCRIPT Conclusion The GemPhos ligand was successfully applied as a ligand for complexation of the noble metals gold, palladium and platinum. The reaction with [Au(tht)2][ClO4] did not result in a
RI PT
homoleptic dinuclear gold complex. Instead, a mononuclear charge-separated compound was obtained, in which the gold atom exhibits an unusual trigonal planar coordination geometry. The palladium and platinum complexes were obtained in very good yields by reaction of the diphosphine ligand with the commercially available metal precursors [MCl2(COD)] in hot
SC
DMSO. All compounds were fully characterized by analytical and spectroscopic techniques
M AN U
and their solid-state structures were established by single crystal X-ray crystallography. The photoluminescent properties were measured at low and ambient temperature revealing different emission patterns, depending on the metal and the coordination mode. For instance, the palladium complex 2 shows near-infrared phosphorescence at temperatures below ~100 K, which was attributed to the metal-centered triplet excited state. No related emission was
TE D
detected for the platinum complex 3. In contrast, the gold complex 1 features a green emission at ~520 nm, which is particularly bright at low temperatures and is similar to that of the
EP
dinuclear GemPhos and PhanePhos gold complexes [47]. Additionally, the obtained compounds appear to be interesting as potential catalysts in cross-coupling or hydrogenation
AC C
reactions.
Experimental
General procedures: All manipulations were performed in Schlenk-type glassware or in an argon-filled MBraun glovebox. Furthermore, gold compounds were handled under the exclusion of light by wrapping the compound-containing flasks in aluminum foil. Visible decomposition (a pink coloration) is observed after a few days for the gold complex (Au
ACCEPTED MANUSCRIPT reduction) although the obtained products can be handled in air and with technical-grade solvents. Prior to use, CH2Cl2 was distilled under nitrogen from CaH2. THF, diethyl ether, and n-pentane were dried using an MBraun solvent purification system (SPS-800). Deuterated solvents were obtained from Carl Roth GmbH (99.5 atom % D). NMR spectra were recorded
residual 1H and
13
RI PT
on a BrukerAvance II 300 MHz or Avance 400 MHz. Chemical shifts are referenced to the C resonances of the deuterated solvents and are reported relative to
tetramethylsilane and 85% phosphoric acid (31P NMR) respectively. IR spectra were
SC
measured on a Bruker Tensor 37. EI-Mass spectra were recorded at 70 eV on a Thermo Scientific DFS. ESI mass spectra were obtained using a FT-ICR (Fourier transform ion
M AN U
cyclotron resonance) IonSpec Ultima mass spectrometer equipped with a 7T magnet (Cryomagnetics). Elemental analyses were carried out with an ElementarVario EL or Micro Cube. [Au(tht)2][ClO4] [59] and GemPhos [46] were prepared according to literature procedures. [PdCl2(COD)] and [PtCl2(COD)] were purchased from Alfa-Aesar and used as
TE D
received.
EP
X-Ray Crystallographic Studies: A suitable crystal was covered in mineral oil (Aldrich) and mounted on a glass fibre. The crystal was transferred directly to the cold stream of a STOE
AC C
IPDS 2. All structures were solved by direct methods or by the Patterson method (SHELXS2013) [60]. The remaining non-hydrogen atoms were located from difference in Fourier map calculations. The refinements were carried out by using full-matrix least-squares techniques on F, minimizing the function (F0 - Fc)2, where the weight is defined as 4F02/2(F02) and F0 and Fc are the observed and calculated structure factor amplitudes using the program SHELXL-2013 [60]. Carbon-bound hydrogen atom positions were calculated. The locations of the largest peaks in the final difference Fourier map calculation, as well as the magnitude of the residual electron densities, in each case were of no chemical significance. Positional
ACCEPTED MANUSCRIPT parameters, hydrogen atom parameters thermal parameters, bond lengths and angles have been deposited as Supporting Information.
RI PT
Photophysical measurements: The PL measurements were performed on a Horiba JobinYvon Fluorolog-322 spectrometer equipped with a closed-cycle optical cryostat (Leybold) operating at ~18-300 K. Hamamatsu R9910 and R5509 photomultipliers were used
SC
as detectors for the emission spectral range of ~300-850 and ~450-1400 nm, respectively. Solid samples (crystalline powders) were measured as dispersions in a thin layer of
M AN U
polyfluoroester oil (ABCR GmbH) placed between two 1 mm quartz plates. All emission spectra were corrected for the wavelength-dependent response of the spectrometer and detector (in relative photon flux units). Emission decay traces were recorded by connecting a photomultiplier to an oscilloscope (typically via a 500 Ohm load) and using a N2–laser for
TE D
pulsed excitation at 337 nm (~2 ns, ~5 µJ per pulse).
EP
[(GemPhos)Au(tht)]ClO4 (1)
[Au(tht)2][ClO4] (118 mg, 0.25 mmol) was dissolved in dichloromethane (10 mL). With
AC C
stirring, GemPhos (144 mg, 0.25 mmol) was added and the resulting mixture was stirred for one hour. After removal of the solvent, the residue was washed with diethyl ether (2 x 5 mL) and the remaining solid was finally dried under high vacuum to obtain the product as a colourless solid. Yield: 183 mg (85 %). Single crystals suitable for X-ray crystallography were obtained by slow diffusion of n-pentane into a solution of 1 in dichloromethane. 1H NMR (300.13 MHz, CD2Cl2): δ (ppm) = 7.65-7.40 (m, 20H, Ph), 6.87 (dd, 3JHH = 7.6 Hz, 4
JHH = 1.5 Hz, 2H, HPC), 6.79 (dt, 3JHH = 7.6 Hz, 4JPH = 2.8 Hz, 2H, HPC), 5.97 (dt, 3JPH = 7.1
Hz, 4JHH = 1.7 Hz, 2H, HPC), 3.40-3.33 (m, 4H, CH2S), 3.26 (dd, 3JHH = 13.8 Hz, 4JHH = 3.8
ACCEPTED MANUSCRIPT Hz, 2H, CH2), 3.08 (dd, 3JHH = 13.0 Hz, 4JHH = 4.3 Hz, 2H, CH2), 2.94 (dd, 3JHH = 13.6 Hz, 4
JHH = 3.6 Hz, 2H, CH2), 2.74 (dd, 3JHH = 13.1 Hz, 4JHH = 4.3 Hz, 2H, CH2), 2.18-2.09 (m,
4H, CH2CH2S).
13
C{1H} NMR (75.48 MHz, CD2Cl2): δ (ppm) = 142.7 (t, JCP = 5.5 Hz),
141.3 (t, JCP = 4.4 Hz), 136.8 (t, JCP = 4.0 Hz), 136.3 (t, JCP = 1.1 Hz), 135.1 (t, JCP = 8.6 Hz),
RI PT
133.7 (t, JCP = 26.2 Hz), 133.6 (t, JCP = 3.2 Hz), 133.4 (t, JCP = 9.2 Hz), 132.6 (m), 132.3 (m), 131.8 (t, JCP = 23.9 Hz), 130.2 (t, JCP = 5.6 Hz), 129.9 (t, JCP = 5.9 Hz), 128.8 (t, JCP = 22.5 Hz), 40.2 (s, CH2S), 35.2 (t, JCP = 4.8Hz, CH2), 35.0 (s, CH2), 31.5 (s, CH2CH2S).
31
P{1H}
SC
NMR (121.48 MHz, CD2Cl2): δ (ppm) = 42.7. IR (ATR): ν ̃ (cm-1) = 3056 (w), 2961 (w), 1617 (w), 1559 (w), 1541 (w), 1457 (m), 1260 (m), 1182 (w), 1163 (w), 1086 (vs), 1023 (s),
M AN U
915 (w), 870 (w), 798 (s), 749 (m), 693 (s), 622 (s), 551 (m), 508 (vs). – Raman (solid state): ν ̃ (cm-1) = 3060 (s), 2934 (m), 1585 (s), 1185 (m), 1096 (w), 1027 (m), 1000 (s), 932 (m), 695 (w), 677 (w), 618 (w), 464 (w), 331 (w), 261 (w). ESI-MS (DCM): m/z = 773.21 ([(GemPhos)Au]+),
257.74
([(GemPhos)Au]3+).
Elemental
analysis
calcd
(%)
for
EP
[(GemPhos)(PdCl2)] (2)
TE D
C44H42AuClO4P2S (961.23): C 54.98, H 4.40, S 3.34; found C 54.50, H 4.67, S 3.14.
AC C
[PdCl2(COD)] (54.5 mg, 0.19 mmol) was dissolved in DMSO (3 mL). With stirring, GemPhos (110 mg, 0.19 mmol) was added and the red solution was heated to 100°C and stirred for one hour. After cooling to room temperature, the product precipitates as yellow crystals, which were collected and dried under vacuum. Yield: 120 mg (84 %). 1H NMR (300.13 MHz, DMSO-d6): δ (ppm) = 8.24 (dd, 3JHH = 11.7 Hz, 7.2 Hz, 4H, Ph), 8.05-7.95 (m, 4H, Ph), 7.63-7.50 (m, 12H, Ph), 6.80 (d, 3JHH = 7.7 Hz, 2H, Ph), 6.44 (dd, 3JHH = 7.6 Hz, 5.0 Hz, 2H, Ph), 5.92 (d, 3JPH = 14.3 Hz, 2H, Ph), 2.90 (d, 3JHH = 7.8 Hz, 2H, CH2), 2.65 (d, 3JHH = 7.5 Hz, 2H, CH2), 2.12-2.07 (m, 4H, CH2). – resonances could be detected.
31
13
C{1H} NMR: Due to low solubility no
P{1H} NMR (121.48 MHz, DMSO-d6): δ (ppm) = 37.8. IR
ACCEPTED MANUSCRIPT (ATR): ν ̃ (cm-1) = 3056 (w), 2935 (w), 2860 (w), 1571 (w), 1480 (m), 1434 (s), 1399 (m), 1313 (w), 1262 (w), 1185 (m), 1158 (w), 1113 (w), 1089 (s), 1058 (w), 1027 (w), 998 (w), 956 (w), 916 (m), 874 (w), 843 (m), 802 (m), 761 (s), 745 (s), 720 (w), 694 (vs), 620 (w), 601 (w), 553 (s), 524 (vs), 511 (s). Raman (solid state): ν ̃ (cm-1) = 3079 (w), 3060 (s), 3003 (w),
RI PT
2957 (m), 2911 (m), 2861 (m), 1586 (s), 1551 (w), 1466 (w), 1439 (w), 1191 (m), 1160 (w), 1091 (w), 1065 (w), 1032 (m), 1003 (vs), 917 (w), 875 (w), 842 (w), 821 (w), 691 (w), 679 (w), 619 (w), 603 (w), 493 (w), 475 (w), 309 (vs), 294 (m), 261 (w), 251 (w), 233 (w), 192
SC
(vs), 164 (s). Elemental analysis calcd (%) for C40H34Cl2P2Pd (753.98): C 62.72, H 4.55;
M AN U
found C 62.39, H 4.80.
[(GemPhos)(PtCl2)] (3)
Synthesis as described for 2, using [PtCl2(COD)] (71 mg, 0.19 mmol) and GemPhos (110 mg,
TE D
0.19 mmol), to obtain the product as colourless crystals. Yield: 130 mg (81 %). 1H NMR (300.13 MHz, DMSO-d6): δ (ppm) = 8.24-8.14 (m, 4H, Ph), 8.06-7.97 (m, 4H, Ph), 7.61-7.50 (m, 12H, Ph), 6.70 (d, 3JHH = 8.0 Hz, 2H, Ph), 6.46 (dd, 3JHH = 7.8 Hz, 4.6 Hz, 2H, Ph), 6.07
EP
(d, 3JPH = 12.3 Hz, 2H, Ph), 2.94-2.86 (m, 2H, CH2), 2.74-2.68 (m, 2H, CH2), 2.30-2.24 (m, 2H, CH2), 2.15-2.08 (m, 2H, CH2). 13C{1H} NMR: Due to low solubility, no resonances could
Hz).
AC C
be detected. 31P{1H} NMR (121.49 MHz, DMSO-d6): δ (ppm) = 15.9 (s), 15.9 (d, 1JPtP = 3656 195
Pt NMR (86.02 MHz, DMSO-d6): δ (ppm) = -4575 (t, 1JPtP = 3656 Hz). IR (ATR): ν ̃
(cm-1) = 3053 (w), 2934 (w), 2860 (w),1572 (w), 1480 (m),1435 (s), 1399 (m), 1312 (w), 1184 (m), 1157 (w), 1115 (w), 1090 (s), 1058 (w), 1028 (w), 999 (w), 956 (w), 917 (m), 875 (w), 844 (m), 820 (w), 761 (s), 746 (s), 722 (w), 694 (vs), 620 (w), 603 (w), 554 (m), 541 (vs), 527 (s), 515 (w). Raman (solid state): ν ̃(cm-1) = 3167 (w), 3140 (w), 3081 (w), 3061 (s), 3003 (w), 2957 (m), 2860 (w), 1587 (s), 1463 (w), 1441 (w), 1194 (m), 1160 (w), 1093 (w), 1029 (m), 1003 (vs), 916 (w), 843 (w), 822 (w), 699 (w), 680 (w), 619 (w), 604 (w), 477 (w), 315
ACCEPTED MANUSCRIPT (s), 295 (m), 263 (w), 236 (w), 192 (s), 174 (s). Elemental analysis calcd (%) for C40H34Cl2P2Pt (842.65): C 57.02, H 4.07; found C 56.32; H 4.32.
RI PT
Crystal data for 1: C44H42AuP2S•ClO4•2(CH2Cl2), M = 1131.04, a = 9.123(2) Å, b = 21.903(4) Å, c = 23.052(5) Å, V = 4606.1(16) Å3, T = 200 K, space group P212121, Z = 4, 33541 reflections measured, 8558 independent reflections (Rint = 0.0785). The final R1 values
SC
were 0.0362 (I > 2σ(I)). The final wR(F2) values were 0.0624 (I > 2σ(I)). The final R1 values were 0.0495 (all data). The final wR(F2) values were 0.0651 (all data).
M AN U
Crystal data for 2: C40H34Cl2P2Pd, M = 753.91, a = 9.5468(8) Å, b = 19.6694(9) Å, c = 17.9286(4) Å, β = 100.226(4)°, V = 3313.2(3) Å3, T = 200 K, space group P21/c, Z = 4, 27007 reflections measured, 6180 independent reflections (Rint = 0.0577). The final R1 values were 0.0393 (I > 2σ(I)). The final wR(F2) values were 0.0756 (I > 2σ(I)). The final R1 values were
TE D
0.0674 (all data). The final wR(F2) values were 0.0824 (all data).
Crystal data for 3: C40H34Cl2P2Pt, M = 842.60, a = 9.5263(3) Å, b = 19.6187(4) Å, c =
EP
17.8612(5) Å, β = 100.372(2)°, V = 3283.60(16) Å3, T = 150 K, space group P21/c, Z = 4, 30396 reflections measured, 6476 independent reflections (Rint = 0.0751). The final R1 values
AC C
were 0.0327 (I > 2σ(I)). The final wR(F2) values were 0.0544 (I > 2σ(I)). The final R1 values were 0.0609 (all data). The final wR(F2) values were 0.0608 (all data).
Crystallographic data (excluding structure factors) for the structures reported in this paper have been deposited with the Cambridge Crystallographic Data Centre as a supplementary publication no. CCDC-1039016 (1), 1039016 (2), and 1039018 (3). Copies of the data can be obtained free of charge on application to CCDC, 12 Union Road, Cambridge CB21EZ, UK (fax: (+(44)1223-336-033; email: [email protected]).
ACCEPTED MANUSCRIPT
Acknowledgements Financial support by the DFG-funded transregional collaborative research centre SFB/TRR 88
RI PT
“Cooperative Effects in Homo- and Heterometallic Complexes (3MET)” is gratefully acknowledged (projects C3 and C7). C.S. gratefully acknowledges the Konrad Adenauer Stiftung for a generous fellowship. S.B. thanks the Studienstiftung des Deutschen Volkes and
SC
the Fonds der Chemischen Industrie (FCI) for generous fellowships.
M AN U
Keywords: gold, luminescence, palladium, paracyclophane, platinum, phosphine
References
J.M. Brunel, Chem. Rev., 105 (2005) 857.
[2]
J.H. Downing and M.B. Smith, in J.A.M.J. Meyer (Editor), Comprehensive
TE D
[1]
Coordination Chemistry II, Pergamon, Oxford, 2003, p. 253. F. Mathey, Chem. Rev., 88 (1988) 429.
[4]
L.D. Quin, A Guide to Organophosphorus Chemistry, John Wiley & Sons, New York,
[5]
AC C
2000.
EP
[3]
P.C.J. Kamer and P.W.N.M.v. Leeuwen (Editors), Phosphorus(III)Ligands in
Homogeneous Catalysis: Design and Synthesis, Wiley, New York, 2012. [6] [7]
M. Schlosser, Organometallics in Synthesis, John Wiley & Sons, Inc., 2013, p. 1. J.-L. Malleron, J.-C. Fiaud and J.-Y. Legros, in J.-L.M.-C.F.-Y. Legros (Editor),
Handbook of Palladium-Catalyzed Organic Reactions, Academic Press, London, 1997. [8]
Á. Molnár (Editor), Palladium-Catalyzed Coupling Reactions: Practical Aspects and
Future Developments, Wiley-VCH Verlag GmbH & Co. KGaA, 2013.
ACCEPTED MANUSCRIPT [9]
M. Muro, A. Rachford, X. Wang and F. Castellano, in A.J. Lees (Editor),
Photophysics of Organometallics, Vol. 29, Springer Berlin Heidelberg, 2010, p. 1. [10]
C. Reber, J.K. Grey, E. Lanthier and K.A. Frantzen, Comments on Inorganic
Chemistry, 26 (2005) 233. E.R.T. Tiekink and J.-G. Kang, Coord. Chem. Rev., 253 (2009) 1627.
[12]
J.A.G. Williams, in V. Balzani and S. Campagna (Editors), Photochemistry and
RI PT
[11]
Photophysics of Coordination Compounds II, Vol. 281, Springer Berlin Heidelberg, 2007, p.
SC
205.
V.W.-W. Yam and E.C.-C. Cheng, Chem. Soc. Rev., 37 (2008) 1806.
[14]
Á. Díez, E. Lalinde and M.T. Moreno, Coord. Chem. Rev., 256 (2011) 2426.
[15]
Chi-Hang Tao and V.W.-W. Yam, J. Photochem. and Photobiol. C: Photochem. Rev.,
M AN U
[13]
10 (2009) 130.
G.J. Hutchings, M. Brust and H. Schmidbaur, Chem. Soc. Rev., 37 (2008) 1759.
[17]
A.S.K. Hashmi, Nach. Chem., 57 (2009) 379.
[18]
A.S.K. Hashmi and G.J. Hutchings, Angew. Chem., Int. Ed., 45 (2006) 7896.
[19]
A.S.K. Hashmi and M. Rudolph, Chem. Soc. Rev., 37 (2008) 1766.
[20]
M. Chen and D.W. Goodman, Chem. Soc. Rev., 37 (2008) 1860.
[21]
R. Coquet, K.L. Howard and D.J. Willock, Chem. Soc. Rev., 37 (2008) 2046.
[22]
A. Corma and H. Garcia, Chem. Soc. Rev., 37 (2008) 2096.
[24]
EP
AC C
[23]
TE D
[16]
C. Della Pina, E. Falletta, L. Prati and M. Rossi, Chem. Soc. Rev., 37 (2008) 2077. J.C. Fierro-Gonzalez and B.C. Gates, Chem. Soc. Rev., 37 (2008) 2127.
[25]
M.C. Gimeno and A. Laguna, Chem. Soc. Rev., 37 (2008) 1952.
[26]
M. Grzelczak, J. Perez-Juste, P. Mulvaney and L.M. Liz-Marzan, Chem. Soc. Rev., 37
(2008) 1783. [27]
H. Hakkinen, Chem. Soc. Rev., 37 (2008) 1847.
[28]
M. Jansen, Chem. Soc. Rev., 37 (2008) 1826.
ACCEPTED MANUSCRIPT [29]
M.J. Katz, K. Sakai and D.B. Leznoff, Chem. Soc. Rev., 37 (2008) 1884.
[30]
T. Laaksonen, V. Ruiz, P. Liljeroth and B.M. Quinn, Chem. Soc. Rev., 37 (2008)
1836. N. Marion and S.P. Nolan, Chem. Soc. Rev., 37 (2008) 1776.
[32]
V. Myroshnychenko, J. Rodriguez-Fernandez, I. Pastoriza-Santos, A.M. Funston, C.
RI PT
[31]
Novo, P. Mulvaney, L.M. Liz-Marzan and F.J. Garcia de Abajo, Chem. Soc. Rev., 37 (2008) 1792.
Y. Ofir, B. Samanta and V.M. Rotello, Chem. Soc. Rev., 37 (2008) 1814.
[34]
B.L.V. Prasad, C.M. Sorensen and K.J. Klabunde, Chem. Soc. Rev., 37 (2008) 1871.
[35]
R.J. Puddephatt, Chem. Soc. Rev., 37 (2008) 2012.
[36]
P. Pyykkö, Chem. Soc. Rev., 37 (2008) 1967.
[37]
H.G. Raubenheimer and S. Cronje, Chem. Soc. Rev., 37 (2008) 1998.
[38]
G. Schmid, Chem. Soc. Rev., 37 (2008) 1909.
[39]
H. Schmidbaur and A. Schier, Chem. Soc. Rev., 37 (2008) 1931.
[40]
R.A. Sperling, P. Rivera Gil, F. Zhang, M. Zanella and W.J. Parak, Chem. Soc. Rev.,
37 (2008) 1896.
TE D
M AN U
SC
[33]
R. Wilson, Chem. Soc. Rev., 37 (2008) 2028.
[42]
H. Schmidbaur and A. Schier, Z. Naturforsch., B J. Chem. Sci., 66 (2011) 329.
[43]
H. Schmidbaur and A. Schier, Chem. Soc. Rev., 41 (2012) 370.
[45]
AC C
[44]
EP
[41]
A. Arcadi, Chem. Rev., 108 (2008) 3266. P.J. Pye, K. Rossen, R.A. Reamer, N.N. Tsou, R.P. Volante and P.J. Reider, J. Am.
Chem. Soc., 119 (1997) 6207. [46]
F.C. Falk, R. Fröhlich and J. Paradies, Chemical Communications, 47 (2011) 11095.
[47]
C. Sarcher, A. Lühl, F.C. Falk, S. Lebedkin, M. Kuhn, C. Wang, J. Paradies, M.M.
Kappes, W. Klopper and P.W. Roesky, Eur J Inorg Chem, (2012) 5033.
ACCEPTED MANUSCRIPT [48]
J.M. Serrano-Becerra, A.F.G. Maier, S. Gonzalez-Gallardo, E. Moos, C. Kaub, M.
Gaffga, G. Niedner-Schatteburg, P.W. Roesky, F. Breher and J. Paradies, Eur J Org Chem, (2014) 4515. J.A. Muir, M.M. Muir and S. Arias, Acta Cryst. Sect. B, 38 (1982) 1318.
[50]
J. Meiners, J.-S. Herrmann and P.W. Roesky, Inorg. Chem., 46 (2007) 4599.
[51]
Z. Assefa, R.J. Staples and J.P. Fackler, Inorg. Chem., 33 (1994) 2790.
[52]
K. Ortner, L. Hilditch, Y. Zheng, J.R. Dilworth and U. Abram, Inorg. Chem., 39
RI PT
[49]
[53]
SC
(2000) 2801.
F.C. Falk, P. Oechsle, W.R. Thiel, C.G. Daniliuc and J. Paradies, Eur J Org Chem,
M AN U
2014 (2014) 3637. [54]
W.L. Steffen and G.J. Palenik, Inorg. Chem., 15 (1976) 2432.
[55]
A.M. Johns, M. Utsunomiya, C.D. Incarvito and J.F. Hartwig, J. Am. Chem. Soc., 128
(2006) 1828.
A. Babai, G.B. Deacon, A.P. Erven and G. Meyer, Z. Anorg. Allg. Chem, 632 (2006)
639. [57]
T. Niksch, H. Görls, M. Friedrich, R. Oilunkaniemi, R. Laitinen and W. Weigand, Eur
EP
J Inorg Chem, (2010) 74. [58]
TE D
[56]
B.-C. Tzeng, S.-C. Chan, M.C.W. Chan, C.-M. Che, K.-K. Cheung and S.-M. Peng,
[59]
AC C
Inorg. Chem., 40 (2001) 6699. R. Usón, A. Laguna, A. Navarro, R.V. Parish and L.S. Moore, Inorg. Chim. Acta, 112
(1986) 205. [60]
G. Sheldrick, Acta Cryst. Sect. A, 64 (2008) 112.
ACCEPTED MANUSCRIPT TOC GemPhos, a diphosphine ligand with a rigid paracyclophane scaffold, was used to prepare
AC C
EP
TE D
M AN U
SC
RI PT
complexes of the noble metals gold, palladium and platinum.
ACCEPTED MANUSCRIPT Highlights
RI PT SC M AN U TE D
•
EP
•
A rigid paracyclophane scaffold, was used to prepare complexes of the noble metals gold, palladium and platinum. In the gold complex the metal atom exhibits an uncommon trigonal planar coordination geometry. The photoluminescent properties of all complexes were determined at low and ambient temperatures.
AC C
•