Coordination chemistry and oxidative addition of trifluorovinylferrocene derivatives

Journal of Fluorine Chemistry 192 (2016) 105–112

Contents lists available at ScienceDirect

Journal of Fluorine Chemistry j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / fl u o r

Coordination chemistry and oxidative addition of trifluorovinylferrocene derivatives Darina Heinrich, Willi Schmolke, Dieter Lentz* Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstraße 34/36, 14195 Berlin, Germany

A R T I C L E I N F O

Article history: Received 31 August 2016 Received in revised form 21 October 2016 Accepted 22 October 2016 Available online 26 October 2016

A B S T R A C T

Complexes using trifluorovinylferrocene and 1,10 -bis(trifluorovinyl)ferrocene as ligands can be obtained by the reaction with a series of fragments of transition metal complexes. Formation of [Pt(h2-trifluorovinylferrocene)(PPh3)2] (1), [{Pt(PPh3)2}2(h2-1,10 -bis(trifluorovinyl)ferrocene)] (2) and [Pt(h2-1,10 -bis(trifluorovinyl)ferrocene)(PPh3)2] (3) were achieved by ligand substitution in [Pt(h2-CH2 = CH2)(PPh3)2]. Treatment of eneacarbonyldiiron with trifluorovinylferrocene provided [Fe (CO)4(h2-trifluorovinylferrocene)] (4). Photolytically activated reactions of [MnCp(CO)3] and [MnCp0 (CO)3] (Cp0 = C5H4CH3) afforded [MnCp(CO)2(h2-trifluorovinylferrocene)] (5a) and [MnCp0 (CO)2(h2trifluorovinylferrocene)] (5b) respectively. [Ni(h2-trifluorovinylferrocene)(Cy2P(CH2)2PCy2)] (6) could be obtained by reaction with [Ni(COD)2] and Cy2P(CH2)2PCy2. Furthermore the CF bond activation by oxidative addition in the presence of lithium iodide yielding two isomers of [PtI{h1-difluorovinylferrocene}(PPh3)2] (7a/7b) is presented. Molecular structures of 1, 4 and 7a were elucidated using X-ray single crystal diffraction. The spectroscopic and structural data of these complexes prove the powerful p acceptor abilities of these ligands. ã 2016 Elsevier B.V. All rights reserved.

1. Introduction Although fluorinated alkenes are important monomers for industrial synthesized polymers like PTFE, PCTFE or PVDF [1–3], their transition metal chemistry is rarely investigated compared to their hydrocarbon analogues. The polymerization of organic fluoropolymers via a free-radical mechanism without the use of coordination catalysts [4–7] might be a reason for the less developed organometallic chemistry of fluoroalkenes. Nevertheless the first examples were already published in the 1960s [8–11]. These studies are focused on simple non functionalized monoalkenes like tetrafluoroethene (TFE) [12–29]. However, there exist remarkably detailed studies on special fluorinated alkenes like for example octafluorocyclooctatetraene [30]. Transition metal complexes with perfluorinated and partially fluorinated allene derivatives or fluorinated butadiene and its substituted analogues are rarely studied [31–36]. However, the increasing interest in activation of the unreactive C F bond refocused the fluoroorganometallic chemistry [37–46]. Recently, we reported on the introduction of trifluorovinyl groups to ferrocene by a Negishi type coupling reaction using iodo

* Corresponding author. E-mail address: [email protected] (D. Lentz). http://dx.doi.org/10.1016/j.jfluchem.2016.10.015 0022-1139/ã 2016 Elsevier B.V. All rights reserved.

precursors and trifluorovinylzinc chloride [47]. Further, we reported on the rich chemistry of trifluorovinylferrocene derivatives, especially on the derivatization at the trifluorovinyl unit by nucleophilic substitution and [2+2]-cycloaddition reactions which could be used for polymerization [47–49]. A nucleophilic substitution with organolithium compounds always takes place in b-position of the C2F3 unit. Herein we report on the coordination chemistry of trifluorovinylferrocene and 1,10 -bis(trifluorovinyl)ferrocene in order to change its reactivity. Activation of the C F bond in a–position should allow to introduce substituents differently. 2. Results and discussions 2.1. Syntheses The synthesis of the h2-trifluorovinylferrocene complexes is outlined in Schemes 1 and 2. Substitution of the labile ethene ligand in [Pt(h2-CH2 = CH2)(PPh3)2] occurs easily at ambient temperature, yielding complex 1 as a yellow crystalline solid. Trifluorovinylferrocene has C1 symmetry and there exist two enantiomers which however are easily interconverted by rotation around the C C bond between the cyclopentadienyl ring and the trifluorovinyl group. Due to the coordination of the bis

106

D. Heinrich et al. / Journal of Fluorine Chemistry 192 (2016) 105–112

Fig. 1. C2-symmetric and the Cs-symmetric diastereomers of [{Pt(PPh3)2}2(h2-1,10 bis(trifluorovinyl)-ferrocene)].

Scheme 1. Reactions of [Pt(h2-CH2 = CH2)(PPh3)2] with trifluorovinylferrocene and 1,10 -bis(trifluorovinyl)ferrocene.

(triphenylphenylphospine)platinum fragment the enantiomers can not be interconverted by rotation around a carbon single bond. Nevertheless only a racemic mixture is obtained. Compound 1 rapidly decomposes in the presence of chlorinated hydrocarbons by forming trifluorovinylferrocene and [PtCl2(PPh3)2]. 1 resembles complexes of various fluoro alkenes with the bis(triphenylphosphine)platinum moiety which have been prepared by Green et al. [50]. Treatment: of 1,10 -bis(trifluorovinyl)ferrocene with [Pt(h2CH2 = CH2)(PPh3)2] provided a mixture of the dicoordinated 2 and the monocoordinated complex 3. Both compounds do not show remarkable differences in their polarity and solubility, therefore column chromatographic separation and fractional crystallization are inadequate for purification and failed. Furthermore, 2 and 3 decompose in contact with silica gel and the formation of fluorinated ferrocenophanes can be observed, which are also formed in the case of 1,10 -bis(trifluorovinyl)ferrocene under redox conditions (Scheme 2) [47]. The formation of analytically pure 2 was accomplished by treating 1,10 -bis(trifluorovinyl)ferrocene with an excess of [Pt(h2CH2 = CH2)(PPh3)2] but 3 could only be obtained in mixture with compound 2 even if a deficit of [Pt(h2-CH2 = CH2)(PPh3)2] is used. The reaction proceeded almost quantitatively, and complex 2 was isolated as an orange solid in 92% yield. Coordination of a second [Pt(PPh3)2] fragment results in a mixture of the C2-symmetric (racemic) and the Cs-symmetric diastereomere, respectively (Fig. 1), as the relative position of the CF and CF2 groups of the trifluorovinyl substituents can be distinguished due to

coordination of a metal center on one side of the substituents plane (Fig. 1). The two diastereomers (2a and 2b) were formed in a ratio of 1:1. Eneacarbonyldiiron can be used as a source for a tetracarbonyliron fragment resulting in the complex 4 by forming pentacarbonyliron as a side product, which can be easily removed in vacuum (Scheme 3). Compound 4 was obtained in 72% yield as a red crystalline solid, which decomposes in contact with air after a few days. Reaction of pentacarbonyliron and trifluorovinylferrocene gave no product at room temperature, reaction at higher temperatures leads to dimerization of the starting material by [2+2]-cycloaddition forming the known cyclobutane derivatives [51]. In contrast to the reaction of dodecacarbonyltriiron with tetrafluorethene which results in tetracarbonyl(octafluoro-butan1,4-diyl)iron [52] no similar C C coupling could be observed. In accordance to literature methods [53] the manganese half sandwich complexes 5a and 5b were synthesized by reactions of photolytically activated [MnCp(CO)3] or [MnCp0 (CO)3] 0 (Cp = C5H4Me) with trifluorovinylferrocene in n-hexane (Scheme 2). The compounds were obtained as red solids after crystallization from n-hexane in 37% (5a) or 68% (5b) yield, respectively. Usage of the solvent stabilized complexes [MnCp (CO)2(thf)] [54,55] for the reaction with trifluorovinylferrocene do not provide isolable quantities of 5a and 5b. Interestingly, treatment of [MnCp*(CO)3] (Cp* = C5Me5) with trifluorovinylferrocene gave no products at all, probably due to the higher bulkiness of the Cp*-ligand. Complexes of zero valent nickel with unsaturated fluorocarbons are rarely found in literature. First examples of TFE nickel complexes with phosphine ligands were described by Stone et al. starting from [Ni(COD)2] or [Ni(CDT)] and subsequent ligand exchange [56,57]. Reaction of [Ni(COD)2] and PPh3 in the presence of TFE gave exclusively the octafluoronickelacyclopentane complex as a result of the reaction with a second TFE molecule by oxidative cyclization [58]. Also, the synthesis of the corresponding nickel complex [Ni(PPh3)2(h2-trifluorovinylferrocene)] starting from [Ni (COD)2] and triphenylphosphine failed and only precipitation of Ni black was observed. The choice of the ligand seems to be important for the stability of the complex. Usage of the better s-donor ligand PCy3 instead of PPh3 in the presence of [Ni(COD)2] and TFE leads to the formation of h2-TFE nickel complex [59] but no reaction with trifluorovinylferrocene could be observed.

Scheme 2. Formation of ferrocenophanes by contact with silca gel of 2 and 3.

D. Heinrich et al. / Journal of Fluorine Chemistry 192 (2016) 105–112

107

of 1:3.7 (cis:trans). If the reaction is performed in toluene the cis isomer is preferred (4.8:1). Lewis acid catalyzed C F activation of perfluoroalkene nickel and palldium complexes has been reported recently by the Ohashi et al. [61]. 2.3. Spectroscopic data

Scheme 3. Synthesis of trifluorovinylferrocene complexes 4–6.

It was considered that bidante ligands like TMEDA or Cy2P (CH2)2PCy2, 1,2-bis(dicyclohexylphosphino)ethane, could promote the stability of a trifluorovinylferrocene nickel complex. The preparation and crystal structure of [Ni(h2-CF2 = CF2)(TMEDA)] was reported by Kaschube et al. [17]. Reaction of TMEDA, [Ni(COD)2] and trifluorovinylferrocene failed. However, in the presence of [Ni (COD)2] and 1 equiv. of the bidentate phosphine ligand Cy2P (CH2)2PCy2, 1,2-bis(dicyclohexyl-phosphino)ethane, trifluorovinylferrocene reacted to the Ni (0) complex 6. Due to the high sensitivity of 6 and its decomposition to elemental nickel, the complex could not be isolated in analytically pure form and its formation was detected only by 19F NMR and 31P NMR spectroscopy. 2.2. Oxidative addition In attempts to achieve CF bond activation by an oxidative addition of the C2F3 unit 1 was treated with Lewis acids to yield a difluorovinylplatinum complex. Reaction of 1 with tin tetrachloride did not give the Pt (II) complex. However trifluorovinylferrocene was recovered and the formation of the very insoluble [PtCl2(PPh3)2] was observed. Hacker et al. reported that Lil [60], which would act as a Lewis acid to improve the elimination ability of fluorine, promotes the oxidative addition of TFE in [Pt(h2-CF2 = CF2)(PPh3)2]. The high lattice energy of LiF might also be important for the occurrence of the oxidative addition at room temperature. Addition of Lil to a solution of 1 in THF promoted the oxidative addition of the C F bond in a-position, which proceeded smoothly to afford two difluorovinylplatinum(II) iodide species (7a/7b) in nearly quantitative yield (Scheme 4). Due to the square planar coordination sphere of the platinum (II) center two isomers are formed in a ratio

Scheme 4. Oxidative addition under lithium fluoride elimination.

The 19F NMR spectra of all products exhibit a typical ABC pattern for the three chemically non-equivalent fluorine nuclei of the trifluorovinyl group. For the platinum complexes 1 (Fig. 2), 2a and 2b the spectra show additional splitting due to the coupling with the 31P nuclei and the 195Pt nuclei, respectively. For the nickel complex 6 additional splitting caused by the coupling with the 31P nuclei is observed. The NMR spectroscopic data extracted from the spectra are summarized in Tables 1 and 2. The chemical shift values of the 19F NMR of the platinum compounds experienced no major deviation from that one of the trifluorovinylferrocene molecule. [51] However, coordination leads to drastically increased geminal coupling constants and decreased vicinal coupling constants. The cis 3J(19FA19FC) coupling constant is too small to be observed. The diastereomers 2a and 2b show nearly identical coupling patterns and chemical shift values which lead to broad signals except for the a fluorine atom of the trifluorovinyl group. For this one two signals with identical splitting can be observed in the 19F NMR. According to the 31P NMR spectrum of compound 1, which exhibits two resonances with different coupling patterns the phosphine ligands are non-equivalent. This indicates a hindered propeller rotation of the ligand. An unambiguous assignment of the resonances to the chemical non-equivalent phosphorus atoms cannot be made. Various platinum alkene complexes with different substituents are reported but no assignment of the phosphorus resonances to the phosphine ligands were made [62–68]. The 31P NMR spectra of 2a and 2b overlap strongly. Chemical shift values and coupling constants of the two diastereomers are almost identical. Due to the complicated spin-system of the platinum complexes 19F- and 31P{1H} NMR spectra of compound 1 were simulated with the program gNMR and confirm coupling constants, which were taken from the recorded spectra [69]. For compound 4, 5a and 5b three signals for the chemically nonequivalent fluorine atoms with a coupling pattern of a doublet of a doublet are expected in the 19F NMR spectra. However, 4, 5a and 5b exhibit only two broad doublets besides one doublet of a doublet. The splitting in two doublets is a consequence of the very small cis 3 J (19FA19FC) coupling constant. The signals of all F-atoms are shifted to higher frequencies in comparison to the free trifluorovinylferrocene molecule [51]. Due to the chirality the ferrocene moiety the 1H NMR spectra exhibit five signals in a ratio of 5:1:1:1:1, one for the unsubstituted and four signals for the substituted cyclopentadienyl ligand. In contrast to trifluorovinylferrocene, which shows two signals with a AA0 BB0 pattern for the substituted cp-ligand. For the Pt(II) complexes (7a/7b) two typical AB pattern are observed in the 19F-spectra with 195Pt satellites. The cis- isomers show a large coupling (33.8 Hz) to one of the phosphorus atoms of the triphenyl phosphine groups (Fig. 3). Cis and trans isomer can be distinguished in the 31P NMR spectra. Due to the chemical equivalence of the two phosphorus atoms in the trans product (7a) a triplet/doublet of doublet with small similar coupling constants between phosphorus and fluorine nuclei is observed. In case of the cis product (7b) the spectrum exhibits two resonances with a coupling pattern of a doublet of doublet of doublet caused by the coupling between the phosphorus atoms and the coupling to the two non-equivalent fluorine nuclei.

108

D. Heinrich et al. / Journal of Fluorine Chemistry 192 (2016) 105–112

Fig. 2.

19

F NMR and

31

Table 1 19 F NMR data of 1, 2a, 2b, 4, 5a, 5b and 6 in comparison to trifluorovinyl-ferrocene (d [ppm], J [Hz]).

d FA

d FB

d FC

2

fc(CF = CF2) 1

101.0 106.9

118.5 118.4

172.5 177.9

30 184

111 57

80 X

2a/2b

105.8 105.8

117.6 117.6

175.8a 176.5a

184 184

59 59

X X

4 5a 5b 6

89.4 89.0 90.2 106.9

92.4 90.1 90.8 113.0

137.7 146.9 147.7 187.1

136 142 143 189

69 71 68 83

X X X X

JAB

3

JBC

3

JAC

a An unambiguous assignment for the two diastereomers 2a and 2b is not possible.

P{1H} NMR spectrum of 1.

In the IR-spectrum of 5a and 5b two very strong absorptions at around 1950 cm1 can be observed resulting from CO-stretching vibrations. The wave numbers correlate with the CO-force constants [70], which give important information on the ligand properties and the p-acceptor abilities of the trifluorovinyl ligand. The force constants k(CO) = 15.45 N cm1for 5a and k(CO) = 15.49 N cm1 for 5b can be compared to that one of [MnCp(CO)2(h2C3H4)] (k(CO) = 15.54 N cm1) [36]. Trifluorovinylferrocene is a better p-accepting ligand as ethene (k(CO) = 15.30 N cm1) but not as strong as CO (k(CO) = 15.77 N cm1) [71]. The iron complex 4 should show four infrared CO stretching vibrations. The observation of only three CO vibrations is due to an overlap. All CO vibrations are observed above 2000 cm1, again demonstrating the good p–acceptor ability of trifluorovinylferrocene ligand.

D. Heinrich et al. / Journal of Fluorine Chemistry 192 (2016) 105–112 Table 2 31 P and

195

Pt-NMR data of compound 1 and 2a/2b (d [ppm], J [Hz]).

d

19

1

31

P 31 P 195 Pt

26 27

7 46 269

27 60 195

35 7 111

– 27 2904

27 – 2724

2904 2724 –

2a/2b

31

26 27

8 48 269

29 59 196

37 5 110

– 28 2920

28 – 2723

2920 2723 –

P P 195 Pt 31

FA

19

FB

19

FC

31

31

P

P

195

Pt

2.4. Crystal structures

109

coordinating C C bond in the non-coordinating ligand [51]. Complex 4 exhibits a larger deviation from the eclipsed position of the cyclopentadienyl ligands (15.19 ) as complex 1. The tilt angle of the cyclopentadienyl units is 1.41. The molecular structure of the trans product (7a) is shown in Fig. 6. The platinum center adopts a slightly distorted square planar coordination geometry and it is coordinated by two PPh3 ligands in trans position. The ORTEP drawing of 7a unambiguously shows that the CF bond cleavage occurs in the a-position of the trifluorovinyl group. The tilt angle of the cyclopentadienyl units is 0.59 and they are nearly in eclipsed position (0.79 deviation). 3. Conclusions

Single crystals of 1 can be grown from a saturated solution in THF at room temperature (Fig. 4). The trifluorovinyl unit shows a loss of planarity as a result of the coordination in accordance with the higher p-character of the hybrid orbitals. This indicates that the contribution of the backdonation from platinum to the p* antibonding orbital of trifluorovinylferrocene must be very large. The C C bond length of 1.447(6) Å is significantly longer than that of a non-coordinating trifluorovinylferrocene molecule [51]. The coordination geometry of the platinum center can be considered as slightly distorted Y shaped trigonal planar, if the midpoint of the C C-double bound of the trifluorovinyl group is assumed to be the coordination center. The deviation from the eclipsed position of the cyclopentadienyl ligands is 5.22 . The tilt angle between the two cp-rings of the ferrocene unit is 1.36 . Single crystals of compound 4 which were suitable for single Xray diffraction analysis could be obtained from a solution in npentane at 30  C. The molecular structure is shown in (Fig. 5). The trifluorovinylferrocene ligand occupies the equatorial position of the slightly distorted trigonal-bipyramidal coordination polyhedra. The carbon atoms of the trifluorovinyl group, the iron atom and the equatorial carbonyl ligands are located in one plane. The metal-carbon distances of the axial and equatorial carbonyl ligands do not exhibit obvious differences in their bond lengths (0.01 Å). This geometry is comparable to the one of tetracarbonyl(tetrafluoroethene)iron, [73] which was structurally studied by gas electron diffraction. The coordination additionally leads to an increased CC bond length (1.413(7) Å) compared to the non-

Fig. 3.

19

We have synthesized the first complexes with trifluorovinylferrocene ligands. An analysis of the vibrational spectroscopic data revealed that trifluorovinylferrocenes are good p-accepting ligands, stronger than ethene but not as strong as the CO ligand. C F bond activation could be achieved by an oxidative addition promoted by lithium iodide affording two difluorovinylplatinum (II) iodide species. 4. Experimental 4.1. General considerations All experiments were performed under argon atmosphere, using standard Schlenk and vacuum line techniques. THF and diethylether were dried over potassium/benzophenone. Toluene, n-pentane, n-hexane and dichloromethane were purified by an MBraun MB SPS-800 solvent system. Trifluorovinylferrocene and 1,10 -bis(trifluorovinyl)ferrocene were prepared according to our previously described method [48] [Pt(h2-C2H4)(PPh3)2] [74] and [Fe2(CO)9] [75] were synthesized according to the literature cymantrene was obtained from Strem Chemicals. Other substances were obtained commercially. NMR spectra in solution were recorded at a Jeol ECS 400 (MHz) spectrometer. IR spectra were recorded on a Nicolet iS10 spectrometer with an ATR Smart Dura Sampl/IR device. Mass spectra were recorded on MAT 711 or Jeol JMS 700 devices.

F NMR spectrum of the reaction of 1 with LiI in toluene.

110

D. Heinrich et al. / Journal of Fluorine Chemistry 192 (2016) 105–112

Fig. 4. Molecular structure (ORTEP [72]) of 1, thermal ellipsoids, probability 50%. Selected bond distances (Å) and angles(deg): Pt – C(1) 2.019(4), Pt C(2) 2.093(4), Pt – P(1) 2.311(1), Pt – P(2) 2.313(1), C(1) – C(2) 1.447(6), C(1) – F(1) 1.379(5), C(1) – F(2) 1.365(5), C(2) – F(3) 1.399(5), C(1) – Pt- C(2) 41.2(2), P(2) – Pt P(1) 105.7(4), F(2) C(1) – F(1) 120.1(3), C(1) – C(2) – C(3) 123.7(4).

4.2. Syntheses 4.2.1. Preparation of [Pt(PPh3)2(h2-trifluorovinylferrocene)] (1) A solution of trifluorovinylferrocene (178 mg, 0.67 mmol) in toluene (2 mL) was added at room temperature to a solution of [Pt (h2-CH2 = CH2)(PPh3)2] (0.5 g, 0.67 mmol) in toluene (5 mL). After 6 h of stirring the resulting suspension was filtrated and the residue was washed with n-hexane (3  3 mL). Evaporation of the

Fig. 5. Molecular Structure (ORTEP [72]) of 4, thermal ellipsoids, probability 50%. Selected bond distances (Å) and angles(deg): C(1)–F(3) 1.372(6), C(1) – F(2) 1.358 (5), C(2) – F(1) 1.392(5), C(1) – C(2) 1.413(7), C(2) – C(3) 1.471(5), Fe(2) – C(1) 1.976 (4), Fe(2) – C(2) 2.068(4), F(2) – C(1) – F(3) 106.4(4), C(1) – C(2) – C(3) 127.1(4), C(1) – Fe(2) – C(2) 40.8(2).

Fig. 6. Molecular Structure (ORTEP [72]) of 7a, thermal ellipsoids, probability 50%. Selected bond distances (Å) and angles (deg): C(1) – C(2) 1.276(12), C(1) – C(3) 1.494 (14), C(1) – Pt(1) 2.025(9), C(2) – F(1) 1.303(11), C(2) – F(2) 1.373(11), Pt(1) – I(1) 2.669(1), Pt(1) – P(1) 2.305(2), Pt(1) – P(2) 2.288(3), F(2) – C(2) – F(1) 106.2(7), C(2) – C(1) – C(3) 121.8(9).

solvent yielded 0.558 g (0.55 mmol, 82%) of a yellow solid. 1H NMR (400 MHz, [D8] THF, 25  C): 3.24 (m, 1H, cp), 3.65 (m, 1H, cp), 3.91 (m, 1H, cp), 3.97 (m, 1H, cp), 4.02 (s, 5H, cp), 6.97–7.31 (m, 30H, C6H5). 19F NMR (376 MHz, [D8] THF, 25  C): 106.9 (m, 2J (19F19F) = 184.0 Hz, J (19F195Pt) = 268.7 Hz, J(19F31P) = 46.4 Hz, J(19F31P) = 7.4 Hz), 118.4 (m, 2J (19F19F) = 184.0 Hz, 3J (19F19F) = 57.2 Hz, J (19F195Pt) = 195.2 Hz, J(19F31P) = 60.0 Hz, J(19F31P) = 27.0 Hz), 177.9 (m, 3J (19F19F) = 57.2 Hz, J (19F195Pt) = 110.6 Hz, J(19F31P) = 6.8 Hz, J(19F31P) = 35.0 Hz). 31P NMR {1H} (162 MHz, [D8] THF, 25  C): 26.1 (m J(31P31P) = 27.4 Hz, J(31P19F) = 7.4 Hz, J(31P19F) = 27.0 Hz, J(31P19F) = 35.0 Hz, J(31P195Pt) = 2904.0 Hz), 27.1 (m J(31P31P) = 27.4 Hz, J(31P19F) = 46.4 Hz, J(31P19F) = 60.0 Hz, J(31P19F) = 6.8 Hz, J(31P195Pt) = 2723.8 Hz). IR(neat): 628 (w), 675.58 (m), 692 (s), 740 (m), 815 (w), 863 (w), 962(m), 1008 (w), 1028 (w), 1046 (w), 1073 (m), 1096 (w), 1183 (w), 1324 (w), 1434 (m), 1479 (w), 1663 (w), 3051 (w) cm1. MS (EI): m/z calcd. for C44H39F3FeP2Pt: 937.1478, found 937.1. M.p.: 176  C. 4.2.2. Preparation of [Pt(PPh3)2(h2-1,10 -bis(trifluorovinyl)-ferrocene)] (2a/2b) To a solution of 1,10 -bis(trifluorovinyl)ferrocene (37 mg, 0.11 mmol) in toluene (5 mL) was added [Pt(h2-CH2 = CH2) (PPh3)2] (190.3 mg, 0.25 mmol) as a solid. After 6 h of stirring at room temperature the precipitate was filtrated and washed with cold n-pentane (3  3 mL). Evaporation of the solvent yielded 183 mg (0.10 mmol, 92%) of 2 as an orange solid. 1H NMR (400 MHz, [D8] THF, 25  C): 3.64 (m, 1H, cp), 3.76 (m, 1H, cp), 4,18 (m, 1H, cp), 4.27 (m, 1H, cp), 4.33 (m, 1H, cp), 4.42 (m, 2H, cp), 4.50 (m, 1H, cp), 7.12 (m 60H, C6H5). 19F NMR (376 MHz, [D8] THF, 25  C): 105.8 (m, 2 19 J ( F19F) = 184.0 Hz, J (19F195Pt) = 269.0 Hz, J(19F31P) = 48.0 Hz, J(19F31P) = 8 Hz), 117.6 (m, 2J (19F19F) = 184.0 Hz, 3J (19F19F) = 59 Hz, J (19F195Pt) = 196 Hz, J(19F31P) = 59 Hz, J(19F31P) = 29 Hz), 175.8/176.5 (m, 3J (19F19F) = 59 Hz, J (19F195Pt) = 110 Hz, J(19F31P) = 5 Hz, J(19F31P) = 35.0 Hz). 31P NMR {1H} (162 MHz, [D8] THF, 25  C): 26.6 (m, J(31P31P) = 28 Hz, J(31P19F) = 8 Hz, J(31P19F) = 29 Hz, J(31P19F) = 37 Hz, J(31P195Pt) = 2920 Hz), 27.6 (m J(31P31P) = 28 Hz, J(31P19F) = 48 Hz, J(31P19F) = 59 Hz, J(31P19F) = 5 Hz, J(31P195Pt) = 2723 Hz). IR(neat): 529 (m), 628

D. Heinrich et al. / Journal of Fluorine Chemistry 192 (2016) 105–112

(w), 673 (m), 691 (s), 741 (m), 820 (w), 860 (w), 963 (m), 1010 (w), 1049 (w), 1093 (m), 1181 (w), 1262 (w), 1326 (w), 1358 (w), 1433 (m), 1479 (w), 3051 (w) cm1. MS (250 V/ESI-TOF): m/z calcd for [C86H68F6FeP4Pt2]+: 1783.280, found 1783.207. M.p.: 184  C. 4.2.3. Preparation of [Fe(CO)4(h2-trifluorovinylferrocene)] (4) Trifluorovinylferrocene (100 mg, 0.37 mmol) was dissolved in dichloromethane (10 mL) and [Fe2(CO)9] (134.6 mg, 0.37 mmol) was added to the solution at room temperature, which was stirred for 8 h. After the volatiles were removed in vacuum, the residue was extracted with pentane. The solvent was evaporated from the extract under vacuum. 4 was crystallized from n-hexane at 30  C yielding 117 mg (0.27 mmol, 72%) of red crystals, which were also suitable for single-crystal X-ray diffraction. 1H NMR (400 MHz, CDCl3, 25  C): 4.20 (s, 5H, cp), 4.26 (m, 1H, cp), 4.37 (m, 1H, cp), 4.42 (m, 1H, cp), 4.54 (m, 1H, cp). 19F NMR (376 MHz, CDCl3, 25  C): 89.4 (dd, 2J(19F19F) = 136 Hz, 3J(19F19F) = 69.0 Hz), 92.4 (d, 2J (19F19F) = 136 Hz), 137.7 (d, 3J(19F19F) = 69.0 Hz). IR(neat): 614 (w), 661 (m), 686 (m), 793.5 (s), 862 (w), 1015 (s), 1070 (s), 1259 (m), 1.411 (w), 20015 (m), 2012 (s), 2046 (s), 2113 (s), 2905 (w), 2962 (m) cm1. M.p.: 176  C. MS (8 kV/EI-TOF): m/z calcd for [C16H9O4F3Fe2] 433.9152, found 433.9143. 4.2.4. Preparation of [MnCp(CO)2(h2-trifluorovinylferrocene)] (5a) A Schlenk tube was charged with trifluorovinylferrocene (100 mg, 0.38 mmol) and [MnCp(CO)3] (76.6 mg, 0.38 mmol) and dissolved in n-hexane (5 mL). After setting the mixture below atmospheric pressure, the orange solution was irradiated by UV light while stirring for 60 min. The Schlenk tube was purged with argon to remove carbon monoxide, which was formed during the reaction. After irridation with UV light for an additional hour in a low pressure atmosphere, the solvent was removed under vacuum. Recrystallization in n-hexane at 30  C yielded 61.9 mg (0.14 mmol, 37%) of 5a as a red solid. 1H NMR (400 MHz, [D6]-Benzene): d = 4.66 (m, 1H, cp), 4.14 (s, 5H, cpFe), 4.04 (m, 1H, cp), 3.94 (s, 5H, cpMn), 3.85 (m, 1H, cp), 3.81 (m, 1H, cp). 13C{1H, 19F} NMR (100 MHz, [D6]-Benzene): d = 228.0 (CO), 149.5 (CF2 = CFfc), 128.8 (CF2 = CFfc), 87.5 (cp), 70.3 (ipso-cp), 69.5 (unsubstituted-cp), 68.9 (cp), 68.7 (cp), 66.2 (cp), 64.6 (cp). 19F NMR (376 MHz, [D6]-Benzene): d = 89.3 (dd, 3J (19F19F) = 71 Hz, 2 19 J ( F19F) = 142 Hz, 1F), 90.1 (d, 2J (19F19F) = 142 Hz, 1F), 146.9 (d, 3J (19F19F) = 71 Hz, 1F). FT-IR (neat): 1986 (n[CO], vs), 1926 (n[CO], vs), 1481 (m), 1412 (m), 1375 (m), 1254 (m), 1215 (w), 1102 (s), 1066 (s), 1015 (s), 955 (s), 863 (m), 843 (s), 815 (s), 729 (s), 645 (s), 608 (s), 576 (vs), 543 (s) cm1. MS (150 V/ESI-TOF): m/z calculated for [C19H14F3FeMnO2]+: 441.9676, found 441.9738. M.p.: 102  C (decomposition). 4.2.5. Preparation of [MnCp0 (CO)2(h2-trifluorovinylferrocene)] (5a) A Schlenk tube was charged with trifluorovinylferrocene (100 mg, 0.38 mmol) and [MnCp0 (CO)3] (82 mg, 0.38 mmol) and dissolved in n-hexane (5 mL). After setting the mixture below atmospheric pressure, the orange solution was irradiated by UV light under stirring for 60 min. The Schlenk tube was purged with argon to remove carbon monoxide, which was formed during the reaction. After irridation with UV light for additional 90 min in a low pressure atmosphere, the solvent was removed under vacuum. Recrystallization in n-hexane by 30  C yielded 118.6 mg (0.26 mmol, 68%) of 5b as a red solid. 1H NMR (400 MHz, [D8]-Toluene): d = 4.66 (m, 1H, cp), 4.16 (s, 5H, unsubstituted-cp), 4.10 (m, 1H, cp), 4.06 (m, 1H, cp), 4.01 (m, 1H, cp), 3.91 (m, 1H, cp), 3.90 (m, 1H, cp), 3.83 (m, 1H, cp), 3.75 (m, 1H, cp), 1.43 (s, 3H, Me). 13C{1H, 19F} NMR (100 MHz, [D8]Toluene): d = 228.8 (CO), 149.6 (CF2 = CFfc), 129.6 (CF2 = CFfc), 92.7 (ipso-cp), 88.6 (cp), 88.3 (cp), 88.1 (cp), 86.4 (cp), 70.3 (ipso-cp), 69.5 (unsubstituted-cp), 68.7 (cp), 68.6 (cp), 66.1 (cp), 64.6 (cp),

111

12.2 (CH3). 19F NMR (376 MHz, [D8]-Toluene): d = 90.2 (dd, 3J [19F19F] = 68 Hz, 2J[19F19F] = 143 Hz, 1F), 90.8 (d, 2J[19F19F] = 143 Hz, 1F), 147.7 (d, 3J[19F19F] = 68 Hz, 1F). FT-IR (neat): 1989 (n[CO], vs), 1928 (n[CO], vs), 1489 (m), 1416 (m), 1378 (m), 1255 (m), 1211 (w), 1100 (s), 1067 (s), 1012 (s), 952 (s), 850 (s), 823 (s), 812 (s), 720 (s), 632 (s), 590 (s), 568 (s), 550 (s), 529 (s) cm1. MS (150 V/ESI-TOF): m/z calculated for [C20H16F3FeMnO2]+: 455.9832, found 455.9819. M.p.: 67  C. 4.2.6. Preparation of [Ni(h2-trifluorovinylferrocene) (Cy2P (CH2)2PCy2)] (6) Bis(1,5-cyclooctadiene)nickel (52 mg, 0.19 mmol) and 1,2-bis (dicyclohexylphosphino)ethane (80 mg, 0.09 mmol) were dissolved in 3 mL toluene. Trifluorovinylferrocene (5 mg, 0.19 mmol) was added at ambient temperatures and the red solution was stirred for 6 h and turned to yellow. NMR data for the reaction mixture. 19F-NMR (376 MHz, toluene): 106.9 (ddd, 2J(19F19F) = 189 Hz, J(19F31P) = 14 Hz, J(19F31P) = 33 Hz, 1F), 113.0 (dddd, 2 19 3 19 J( F19F) = 189 Hz, J( F19F) = 83 Hz, J(19F31P) = 38 Hz, 19 31 3 19 19 J( F P) = 52 Hz, 1F), 187.1(ddd, J( F F) = 83 Hz, J(19F31P) = 33 Hz, J(19F-31P) = 19 Hz, 1F) ppm. 31P NMR {1H} (162 MHz, toluene): 64.2 (dddd, J(31P31P) = 52 Hz, J(31P19F) = 14 Hz, J(31P19F) = 38 Hz, J(31P19F) = 33 Hz, 1P), 56.0 (dddd, J(31P31P) = 52 Hz, J(31P19F) = 33 Hz, J(31P19F) = 52 Hz, J(31P19F) = 19 Hz, 1P) ppm. 4.2.7. Preparation of [PtI{h1-difluorovinylferrocene}(PPh3)2] (7a/7b) A solution of lithium iodide (7 mg, 0.05 mmol) in tetrahydrofurane (3 mL) was added to a suspension of [(PPh3)2Pt(h2trifluorovinylferrocene)] (50 mg, 0.05 mmol) in tetrahydrofurane (3 mL) at ambient temperatures. After 3 h the solvent was removed under vacuum and the product was extracted with toluene (5 mL). Recrystallization from n-pentane yielded 52 mg (0.04 mmol, 96%) of a mixture of 7a and 7b in a ratio of 3.7:1 as an orange solid. Reaction in toluene leads to an isomer ratio of 1:4.8. trans-isomer (7a): 1H NMR (400 MHz, [D6]-Benzene): 3.66 (m, 2H, cp), 3.88 (s, 5H, unsubstituted-cp), 3.98 (m, 2H, cp), 6.91–7.06 (m, 20H, Ph), 7.72–7.84 (m, 10H, Ph) ppm. 19F NMR (376 MHz, [D6]-Benzene): 73.9 (dt, 2J(19F19F) = 60.2 Hz, J(19F31P) = 4.3 Hz, J(19F195Pt) = 142.4 Hz, 1F), 79.2 (dt, 2J(19F19F) = 60.2 Hz, J(19F31P) = 4.3 Hz, J(19F195Pt) = 196.2 Hz, 1F) ppm.31P-NMR {1H} (162 MHz, [D6]Benzene): 18.2 (t, J(31P19F) = 4.1 Hz, J(31P195Pt) = 2950 Hz, 2P) ppm. cis-isomer (7b): 1H NMR (400 MHz, [D6]-Benzene): 3.77 (m, 2H, cp), 4.15 (m, 2H, cp), 4.39 (s, 5H, unsubstituted-cp), 7.60–7.39 (m, 20H, Ph), 7.92–7.84 (m, 10H, Ph) ppm. 19F- NMR (376 MHz, [D6]-Benzene): 75.1 (dd, 2J(19F19F) = 60.2 Hz, J(19F195Pt) = 120.3 Hz, J(19F31P) = 33.8 Hz, 1F), 79.2 (d, 2J(19F19F) = 60.2 Hz, J(19F195Pt) = 188.0 Hz, 1F) ppm. 31P NMR {1H} (162 MHz, [D6]Benzene): 14.9 (ddd, J(31P31P) = 16 Hz, J(31P19F1) = 5 Hz, J(31P19F2) = 7 Hz, J(31P195Pt) = 2683 Hz, 1P); 12.8 (ddd, J(31P31P) = 16 Hz, J(31P19F1) = 5 Hz, J(31P19F2) = 34 Hz, J(31P195Pt) = 3992 Hz, 1P) ppm. FT-IR(neat): 528.7 (m), 628.3 (w), 673.1 (m), 691.2 (s), 741.3 (m), 819.6 (w), 860.1 (w), 963.3 (m), 1010.0 (w), 1048.6 (w), 1093.32 (m), 1181.4 (w), 1261.5 (w), 1325.6 (w), 1357.7 (w), 1433.4 (m), 1478.8 (w), 3051.4 (w) cm1. MS (250 V/ ESI-TOF): m/z calculated for [C48H39F2FeP2PtI+H]+: 1093.05369, found 1093.0521. M.p.: 162  C. 4.3. Crystal structure data CCDC 1403267 (1), CCDC 1403265 (4) and CCDC-1403266 (7a) contains the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.

112

D. Heinrich et al. / Journal of Fluorine Chemistry 192 (2016) 105–112

Acknowledgements Support by the Deutsche Forschungsgemeinschaft GRK 1582/2 “Fluorine as a key element” and the Deutsche Forschungsgemeinschaft DFG Le423/17-1 is gratefully acknowledged. We thank Solvay Fluor GmbH for a gift of 1,1,1,2-tetrafluoroethane. References [1] B. Ameduri, B. Boutevin, J. Fluor. Chem. 104 (2000) 53–62. [2] G. Hougham, Fluoropolymers, Kluwer Academic/Plenum, New York, 1999. [3] J. Scheirs, Modern Fluoropolymers: High Performance Polymers for Diverse Applications, Wiley Chichester, New York, 1997. [4] G.J.P. Britovsek, V.C. Gibson, D.F. Wass, Angew. Chem. 111 (1999) 448–468. [5] G.J.P. Britovsek, V.C. Gibson, D.F. Wass, Angew. Chem. Int. Ed. 38 (1999) 428– 447. [6] H.C.L. Abbenhuis, Angew. Chem. 111 (1999) 1125–1127. [7] H.C.L. Abbenhuis, Angew. Chem. Int. Ed. 38 (1999) 1058–1060. [8] F.A. Stone, J. Fluor. Chem. 100 (1999) 227–234. [9] F.G.A. Stone, Pure Appl. Chem. 30 (1972). [10] P. Treichel, F.G.A. Stone, Advances in Organometallic Chemistry, 1, Elsevier, 1964, pp. 143–220. [11] M.D. Rausch, Trans. N. Y. Acad. Sci. 28 (1966) 611–622. [12] M. Ohashi, T. Kambara, T. Hatanaka, H. Saijo, R. Doi, S. Ogoshi, J. Am. Chem. Soc. 133 (2011) 3256–3259. [13] O.J. Curnow, R.P. Hughes, E.N. Mairs, A.L. Rheingold, Organometallics 12 (1993) 3102–3108. [14] O.J. Curnow, R.P. Hughes, A.L. Rheingold, J. Am. Chem. Soc. 114 (1992) 3153– 3155. [15] A.K. Burrell, G.R. Clark, C.E.F. Rickard, W.R. Roper, A.H. Wright, J. Chem. Soc. Dalton Trans. (1991) 609. [16] P.J. Brothers, A.K. Burrell, G.R. Clark, C.E. Rickard, W.R. Roper, J. Organomet. Chem. 394 (1990) 615–642. [17] W. Kaschube, W. Schröder, K.R. Pörschke, K. Angermund, C. Krüger, J. Organomet. Chem. 389 (1990) 399–408. [18] J.A.K. Howard, S.A.R. Knox, N.J. Terrill, M.I. Yates, J. Chem. Soc. Chem. Commun. (1989) 640. [19] R.R. Burch, R.L. Harlow, S.D. Ittel, Organometallics 6 (1987) 982–987. [20] J.A. Howard, P. Mitrprachachon, A. Roy, J. Organomet. Chem. 235 (1982) 375– 381. [21] N.C. Rice, J.D. Oliver, Acta Crystallogr. B Struct. Crystallogr. Cryst. Chem. 34 (1978) 3748–3751. [22] M. Green, J.A.K. Howard, J.L. Spencer, F.G.A. Stone, J. Chem. Soc. Chem. Commun. (1975) 449. [23] D.R. Russell, P.A. Tucker, J. Chem. Soc. Dalton Trans. (1975) 1752. [24] J.M. Baraban, J.A. McGinnety, J. Am. Chem. Soc. 97 (1975) 4232–4238. [25] J. Browning, B.R. Penfold, J. Chem. Soc. Chem. Commun. (1973) 198. [26] L.J. Guggenberger, R. Cramer, J. Am. Chem. Soc. 94 (1972) 3779–3786. [27] J.A. Evans, D.R. Russell, J. Chem. Soc. D (1971) 197. [28] J.N. Francis, A. McAdam, J.A. Ibers, J. Organomet. Chem. 29 (1971) 131–147. [29] P.B. Hitchcock, M. McPartlin, R. Mason, J. Chem. Soc. D (1969) 1367. [30] R.P. Hughes, Adv. Organomet. Chem. 31 (1990) 183–267. [31] C. Ehm, F.A. Akkerman, D. Lentz, J. Fluor. Chem. 131 (2010) 1173–1181. [32] M.F. Kühnel, D. Lentz, Dalton Trans. 39 (2010) 9745. [33] F.A. Akkerman, D. Lentz, Angew. Chem. Int. Ed. 46 (2007) 4902–4904.

[34] R.P. Hughes, R.B. Laritchev, L.N. Zakharov, A.L. Rheingold, J. Am. Chem. Soc. 126 (2004) 2308–2309. [35] S. Arimitsu, B. Xu, T.L. Kishbaugh, L. Griffin, G.B. Hammond, J. Fluor. Chem. 125 (2004) 641–645. [36] D. Lentz, N. Nickelt, S. Willemsen, Chem. Eur. J. 8 (2002) 1205. [37] M.F. Kuehnel, D. Lentz, T. Braun, Angew. Chem. 125 (2013) 3412–3433. [38] M.F. Kuehnel, D. Lentz, T. Braun, Angew. Chem. Int. Ed. 52 (2013) 3328–3348. [39] M. Ohashi, H. Saijo, M. Shibata, S. Ogoshi, Eur. J. Org. Chem. 2013 (2013) 443– 447. [40] T. Braun, F. Wehmeier, Eur. J. Inorg. Chem. 2011 (2011) 613–625. [41] H. Amii, K. Uneyama, Chem. Rev. 109 (2009) 2119–2183. [42] Comprehensive Organometallic Chemistry III, in: R. Perutz, T. Braun (Eds.), Elsevier, 2007. [43] H. Torrens, Coord. Chem. Rev. 249 (2005) 1957–1985. [44] U. Mazurek, H. Schwarz, Chem. Commun. (2003) 1321. [45] M. Aizenberg, D. Milstein, Science 265 (1994) 359–361. [46] J.L. Kiplinger, T.G. Richmond, C.E. Osterberg, Chem. Rev. 94 (1994) 373–431. [47] M. Roemer, D. Lentz, Chem. Commun. 47 (2011) 7239. [48] M. Roemer, Y.K. Kang, Y.K. Chung, D. Lentz, Chem. Eur. J. 18 (2012) 3371–3389. [49] M. Roemer, D. Heinrich, Y.K. Kang, Y.K. Chung, D. Lentz, Organometallics 31 (2012) 1500–1510. [50] M. Green, R.B.L. Osborn, A.J. Rest, F.G.A. Stone, J. Chem. Soc. A (1968) 2525. [51] M. Roemer, D. Lentz, Eur. J. Inorg. Chem. (2008) 4875–4878. [52] H.H. Hoehn, L. Pratt, K.F. Watterson, G. Wilkinson, J. Chem. Soc. (1961) 2738– 2745. [53] M. Baudler, G. Brauer, Handbuch der Präparativen Anorganischen Chemie in drei Bänden, 3rd edn., Ferdinand Enke, Stuttgart, 1975-1981. [54] J.K. Klassen, M. Selke, A.A. Sorensen, G.K. Yang, J. Am. Chem. Soc. 112 (1990) 1267–1268. [55] W. Strohmeier, Angew. Chem. Int. Ed. Engl. 3 (1964) 730–737. [56] A. Greco, M. Green, S.K. Shakshooki, F.G.A. Stone, J. Chem. Soc. D (1970) 1374. [57] P.K. Maples, M. Green, F.G.A. Stone, J. Chem. Soc. Dalton Trans. (1973) 388. [58] C.S. Cundy, M. Green, F.G.A. Stone, J. Chem. Soc. A (1970) 1647. [59] M. Ohashi, M. Shibata, H. Saijo, T. Kambara, S. Ogoshi, Organometallics 32 (2013) 3631–3639. [60] M. Hacker, G. Littlecott, R. Kemmitt, J. Organomet. Chem. 47 (1973) 189–193. [61] (a) M. Ohashi, M. Shibata, S. Ogoshi, Angew. Chem. Int. Ed. 53 (2014) 13578– 13582; (b) M. Ohashi, M. Shibata, H. Saijo, T. Kambara, S. Ogoshi, Organometallics 32 (2013) 3631–3639. [62] Comprehensive Organometallic Chemistry II, in: G. Brent Young (Ed.), Elsevier, 1995. [63] Acta Hydrochim. Hydrobiol. 21 (1993) 123. [64] J.G. Verkade, L.D. Quin, Phosphorus-31 NMR Spectroscopy in Stereochemical Analysis, VCH Publishers, Deerfield Beach, Fla, 1987. [65] G. Pellizer, M. Graziani, M. Lenarda, B.T. Heaton, Polyhedron 2 (1983) 657–661. [66] Comprehensive Organometallic Chemistry, in: F. Hartley (Ed.), Elsevier, 1982. [67] Y. Koie, S. Shinoda, Y. Saito, J. Chem. Soc. Dalton Trans. (1981) 1082. [68] P.B. Hitchcock, B. Jacobson, A. Pidcock, J. Chem. Soc. Dalton Trans. (1977) 2038. [69] Peter H.M. Budzelaar, gNMR Version 5.0, Adept Scientific plc, UK, 2002. [70] F.A. Cotton, C.S. Kraihanzel, J. Am. Chem. Soc. 84 (1962) 4432–4438. [71] H. Haas, J. Chem. Phys. 47 (1967) 2996. [72] L.J. Farrugia, J. Appl. Crystallogr. 30 (1997) 565. [73] B. Beagley, D.G. Schmidling, D.W.J. Cruickshank, Acta Crystallogr. B Struct. Crystallogr. Cryst. Chem. 29 (1973) 1499–1504. [74] C.D. Cook, G.S. Jauhal, J. Am. Chem. Soc. 90 (1968) 1464–1467. [75] D. Keeley, R. Johnson, J. Inorg. Nucl. Chem. 11 (1959) 33–41.