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Synthesis and structural characterization of new p-ferrocenylphenylacetylene bridged cobalt carbonyl clusters
Polyhedron 26 (2007) 4981–4985 www.elsevier.com/locate/poly
Synthesis and structural characterization of new p-ferrocenylphenylacetylene bridged cobalt carbonyl clusters Li-Ying Wang a, Quan-Ling Suo a
a,*
, Li-Min Han a, Yi-Bing Wang a, Lin-Hong Weng
b
Chemical Engineering College, Inner Mongolia University of Technology, Hohhot, 010051, PR China b Department of Chemistry, Fudan University, Shanghai, 200433, PR China Received 3 June 2007; accepted 1 July 2007 Available online 24 August 2007
Abstract A new ferrocenylphenyl butadiynyl compound Fc–C6H4–(C„C)2–C6H5 (L) has been synthesized by the Glaser cross-coupling reaction and three new complexes with a 4-ferrocenylphenyl-l-alkyne-dicobalt moiety, [Fc–C6H4–(C„C)n–R][Co2(CO)6]n 0 [Fc = C5H5FeC5H4, R = H, n = 1, n 0 = 1 (1); R = C6H5, n = 2, n 0 = 2 (2); R = Fc-C6H4, n = 2, n 0 = 2 (3) ], were obtained in the reaction of p-ferrocenylphenylacetylene compounds with Co2(CO)8. Compounds L, 1, 2 and 3 were characterized by elemental analysis, IR, 1 H, 13C NMR and MS. The molecular and crystal structures of compounds L and 2 have been determined by X-ray single crystal analysis. There is a linear C5H4–C6H4–(C„C)2–C6H5 linkage in compound L, and the terminal ferrocenylphenyl and phenyl groups in complex 2 are a cis arrangement. 2007 Elsevier Ltd. All rights reserved. Keywords: Ferrocenylphenyl alkyne; l-Alkyne dicobalt; Molecular structure; Single crystal analysis
1. Introduction Metallic p-conjugated complexes have recently attracted considerable interest due to their physical and chemical properties, leading to potential electrical applications such as molecular wires for the construction of nanoscale electronic devices [1–7]. There has been much research on the coordination of conjugated alkynes to cobalt compounds [8–10]. Many works on the molecular design and synthesis of compounds with two transition metal terminals linked by a p-conjugated system have been published and the electronic communication between the two transition metal end groups has been revealed [11–16]. Compounds with phenyl and alkyne groups can be starting compounds for the synthesis of polynuclear metal complexes because of their reactivity with transition-metal clusters [17,18]. Therefore, studies on the reactions of p-conjugated diynes containing ferrocenyl and phenyl groups with metal carbonyl *
Corresponding author. Tel./fax: +86 471 6575796. E-mail address: [email protected] (Q.-L. Suo).
0277-5387/$ - see front matter 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.poly.2007.07.017
compounds have continuously appeared [19]. Our group has recently synthesized some p-conjugated compounds with phenyl, biphenyl and ferrocenyl groups and has studied the reactivity of Co2(CO)8 with the unsaturated C„C chain of these compounds [20–22]. Here, we describe the preparation and characterization of the new compounds Fc–C6H4–C„C–C„C–C6H5 (L) and [Fc–C6H4–(C„C)n–R][Co2(CO)6]n 0 [Fc = C5H5FeC5H4, R = H, n = 1, n 0 = 1 (1); R = C6H5, n = 2, n 0 = 2 (2); R = Fc-C6H4, n = 2, n 0 = 2 (3)], and the molecular and crystal structures of compounds L and 2 have been determined by single-crystal X-ray diffraction analysis. To our knowledge, the syntheses and structures of compounds L, 1, 2 and 3 have not been reported previously. 2. Results and discussion 2.1. Synthesis and characterization of compounds L, 1, 2 and 3 The new compound Fc–C6H4–(C„C)2–C6H5 (L) was synthesized by the Glaser cross-coupling reaction [23] of
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Fc–C6H4–C„CH and C6H5–C„CH. Complexes [Fc– C6H4–(C„C)n–R][Co2(CO)6]n 0 [Fc = C5H5FeC5H4, R = H, n = 1, n 0 = 1 (1); R = C6H5, n = 2, n 0 = 2 (2); R = Fc– C6H4, n = 2, n 0 = 2 (3)] were obtained by the reactions of compounds Fc–C6H4–C„CH [24], Fc–C6H4–C„C– C„C–C6H5 (L) and Fc–C6H4–(C„C)2–C6H4–Fc [25] with excess Co2(CO)8, respectively (see Scheme 1). Compound L contains a linear C5H4–C6H4–(C„C)2–C6H5 linkage. One alkyne bond (for 1) or two alkyne bonds (for 2 and 3) coordinate with the Co–Co bonds in complexes 1, 2 and 3. Compound L is an orange yellow, air-stable crystalline compound that is soluble in both non-polar solvents such as benzene and polar solvents such as diethyl ether or chloroform. Complexes 2 and 3 are black, air-stable crystalline compounds, with solubilities similar to compound L. Complex 1 is a purple-black, air-stable crystalline compound, but it is air-sensitive in solution. The absorbing peaks of the FT-IR spectra in the region 2100–2013 cm1 correspond to the stretching vibrations of the coordinated CO groups, which confirm that there are coordinated Co2(CO)6 species. 1H and 13C NMR spectra reflect that there are the appropriate Fc, Ph, C„C and CO groups in L, 1, 2 and 3. The structure and composition of compounds L, 1, 2 and 3 are proven further by their elemental analyses and MS data. 2.2. Molecular structures of compounds L and 2 The crystal and molecular structures of compounds L and 2 were determined by X-ray single crystal analysis. Crystal data and relevant structural parameters are given in Table 1. The structures with the atom numbering schemes are shown in Figs. 1 and 2, and the selected bond lengths and angles are listed in Table 2. The molecule of compound L contains a butadiynyl chain, of which the terminal groups are phenyl and p-ferrocenylphenyl groups (see Fig. 1). The bond distances ˚ ] and C(14)–C(15) [1.195(5) A ˚] C(12)–C(13) [1.198(5) A show there are two C„C triple bonds in L. The shorter ˚ ], C(13)–C(14) [1.370(6) A ˚ ] and C(9)–C(12) [1.436(5) A ˚ ] bond distances, compared to the C(15)–C(16) [1.437(5) A classical single bond length, are the result of electron delo-
C
CH
Table 1 Crystal data and structure refinement for L, 2 Identification code
L
2
Empirical formula Formula weight Temperature (K) ˚) Wavelength (A Crystal system Space group
C26H18Fe 386.25 298(2) 0.71073 triclinic P 1
C38H18O12Co4Fe 958.09 298(2) 0.71073 monoclinic P2(1)/n
7.158(3) 9.875(4) 14.643(6) 76.357(6) 82.288(5) 69.624(5) 941.4(6), 2 1.363 0.807 400 0.15 · 0.15 · 0.10 1.43–26.01 8 6 h 6 8, 12 6 k 6 10, 16 6 l 6 18 4300 3591 (0.0286) 97.2% 0.9236 and 0.8885 3591/0/244 0.987 R1 = 0.0572, wR2 = 0.1102 R1 = 0.0861, wR2 = 0.1186 0.506 and 0.277
19.051(4) 9.6101(19) 22.547(4) 90 113.143(2) 90 3795.7(13), 4 1.677 2.146 1904 0.15 · 0.12 · 0.08 1.19–26.00 22 6 h 6 23, 11 6 k 6 5, 27 6 l 6 27 16 124 7419 (0.0361) 99.4% 0.8470 and 0.7390 7419/0/496 1.237 R1 = 0.0691, wR2 = 0.1463 R1 = 0.0899, wR2 = 0.1534 0.478 and 0.422
Unit cell dimensions ˚) a (A ˚) b (A ˚) c (A a () b () c () ˚ 3), Z Volume (A Calculated density (Mg/m3) Absorption coefficient (mm1) F(0 0, 0) Crystal size (mm) h Range for data collection () Limiting indices
Reflections collected Independent reflections (Rint) Completeness to h Maximum and minimum transmission Data/restraints/parameters Goodness-of-fit on F2 Final R indices [I > 2r(I)] R indices (all data) Largest difference peak and hole ˚ 3) (e A
calization of the C4 diyne chain, phenyl and ferrocenylphenyl units. The data of the bond angles [C(9)–C(12)–C(13), 178.9(4); C(12)–C(13)–C(14), 177.1(4); C(13)–C(14)– C(15), 178.8(4); C(14)–C(15)–C(16), 178.7(4)] demonstrate the carbon chain C(9)C(12)C(13)C(14)C(15)C(16) has a nearly linear structure. The molecule of complex 2 contains two approximately tetrahedral l-alkyne dicobalt moieties bound to the ferr-
Co2(CO)8 equal
Fe
CH
C Fe (CO)3Co
Co(CO)3
1 Co(CO)3
(CO)3Co
_C
C C
_
Co2(CO)8
C
excess
Fe
_C
C C
2
L
(CO)3Co
(CO)3Co
_C C C C Fe
_
Co2(CO)8 Fe
excess
Scheme 1.
C
Fe Co(CO)3
Co(CO)3
_C
C C
3
(CO)3Co
C
Fe
_ Fe
Co(CO)3
L.-Y. Wang et al. / Polyhedron 26 (2007) 4981–4985
Fig. 1. Molecular structure of L.
Fig. 2. Molecular structure of 2.
ocenylphenyl and phenyl units. In 2 the CO ligands coordinated to the Co atoms are terminal (vide IR) and the alkyne bonds adopt the typical l2-g2 coordination fashion, with the alkyne bond lying essentially perpendicular to the Co–Co bond in the C2Co2 units. The Co–Co bond dis˚ , are classical values for tances, in the range 2.452–2.461 A Co–Co bond lengths of similar complexes. The coordi˚; nated alkyne bond lengths of 2 [C(24)–C(25)1.349(7) A ˚ C(26)–C(27)1.355(8) A] are longer than that of L [C(12)– ˚ ) and C(14)–C(15) (1.195(5) A ˚ )] and are C(13) (1.198(5) A similar to the classical alkene bond length due to Co2(CO)6 units coordinated by diyne bonds. In complex 2 the bond
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angle data [C(21)–C(24)–C(25), 140.2(5); C(24)–C(25)– C(26), 141.1(5); C(25)–C(26)–C(27), 141.3(5); C(26)– C(27)–C(28), 144.9(5)] demonstrate the construction of L is altered from a linear to a non-linear structure while L is coordinated to the Co2(CO)6 units. It is noteworthy that the Co2(CO)6 units are coordinated to the alkyne bond in a trans arrangement and the two terminal groups (phenyl and ferrocenylphenyl) are in a cis arrangement (see Fig. 2). Because of the large ferrocenylphenyl substituted group, the molecular structure of 2 is quite different from [Fc–C„C–C„C–C6H5][Co2(CO)6]2 [20]. In L the dihedral angle [1.85(0.28)] between plane 1 [C(22)C(23)C(24)C(25)C(26)] and plane 2 [C(1)C(2)C(3)C(4)C(5)] shows that the two Cp planes in the Fc group are nearly parallel. The dihedral angle [16.15(0.21)] between plane 2 and plane 3 [C(6)C(7)C(8)C(9)C(10)C(11)] is deviated from parallel, and the dihedral angle [74.39(0.13)] between the two phenyl rings, that is plane 3 and plane 4 [C(16)C(17)C(18)C(19)C(20)C(21)], is nearly perpendicular. In 2 the dihedral angle [0.45(0.59)] of the two Cp rings shows that they are nearly parallel. It is interesting that the dihedral angle [9.20(0.47)] between the planes of the Cp ring [C(13)C(14)C(15)C(16)C(17)] and the phenyl ring [C(18)C(19)C(20)C(21)C(22)C(23)] becomes smaller than that of L. The dihedral angle between the two phenyl rings [C(18)C(19)C(20)C(21)C(22)C(23)] and [C(28)C(29)C(30)C(31)C(32)C(33)] alters from 74.39(0.13) to 86.71(0.23). The changes of the dihedral angles in 2 show that the increased steric requirements on the coordinated Co2(CO)6 groups lead to a twisting of the substituents away from each other. 3. Experimental 3.1. General procedures All reactions and manipulations were carried out using standard Schlenk techniques under an atmosphere of pure
Table 2 ˚ ) and angles () for L, 2 Selected bond lengths (A Bond lengths
Bond angles
L C(1)–C(5) C(5)–C(6) C(6)–C(11) C(8)–C(9) C(9)–C(12)
1.432 (5) 1.468(5) 1.390(5) 1.395(5) 1.436(5)
C(12)–C(13) C(13)–C(14) C(14)–C(15) C(15)–C(16) C(16)–C(17)
1.198(5) 1.370(6) 1.195(5) 1.437(5) 1.387(5)
C(3)–C(4)–C(5) C(4)–C(5)–C(6) C(5)–C(6)–C(7) C(8)–C(9)–C(12) C(9)–C(12)–C(13)
2 Co(1)–Co(2) Co(1)–C(24) Co(1)–C(25) Co(2)–C(24) Co(2)–C(25) Co(3)–Co(4) Co(3)–C(26) Co(3)–C(27)
2.452(1) 1.952(5) 1.989(6) 1.975(5) 1.967(5) 2.461(1) 1.963(5) 1.942(6)
Co(4)–C(26) Co(4)–C(27) C(20)–C(21) C(21)–C(24) C(24)–C(25) C(25)–C(26) C(26)–C(27) C(27)–C(28)
1.952(5) 1.968(5) 1.385(8) 1.449(7) 1.349(7) 1.435(8) 1.355(8) 1.463(8)
C(24)–Co(1)–Co(2) C(24)–Co(2)–Co(1) C(25)–Co(1)–Co(2) C(25)–Co(2)–Co(1) C(26)–Co(3)–Co(4) C(26)–Co(4)–Co(3) C(27)–Co(3)–Co(4) C(27)–Co(4)–Co(3)
109.1(4) 127.2(4) 121.4(3) 120.7(4) 178.9(4)
C(12)–C(13)–C(14) C(13)–C(14)–C(15) C(14)–C(15)–C(16) C(16)–C(17)–C(18) C(15)–C(16)–C(21)
177.1(4) 178.8(4) 178.7(4) 120.6(4) 121.4(4)
51.8(2) 51.0(2) 51.3(2) 52.1(2) 50.9(2) 51.3(2) 51.5(2) 50.5(2)
C(15)–C(16)–C(17) C(17)–C(18)–C(19) C(20)–C(21)–C(24) C(21)–C(24)–C(25) C(24)–C(25)–C(26) C(25)–C(26)–C(27) C(26)–C(27)–C(28) C(27)–C(28)–C(29)
108.7(6) 121.1(5) 122.0(5) 140.2(5) 141.1(5) 141.3(5) 144.9(5) 121.5(6)
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L.-Y. Wang et al. / Polyhedron 26 (2007) 4981–4985
nitrogen. Solvents were purified, dried and distilled under a nitrogen atmosphere prior to use. Reactions were monitored by TLC. Chromatographic separations and purifications were performed on 200–300 mesh silica gel. Co2(CO)8 was purchased from Alfa Aesar. The ligands Fc–C6H4– C„CH and Fc–C6H4–(C„C)2–C6H4–Fc were prepared according to the literature methods [24,25]. IR spectra were recorded on a Nicolet FT-IR spectrometer, as KBr discs. Elemental analyses were carried out on an Elementar var III-type analyzer. 1H and 13C NMR spectra in CDCl3 were recorded on a Bruker Avance500 MHz spectrometer. The mass spectra were determined by using a Polaris Q MS, Micromass LCT instrument. Melting points were determined by using XT-4 melting point apparatus. 3.2. Synthesis of compound Fc–C6H4–(C„C)2–C6H5 (L) Fc–C6H4–C„CH (57 mg, 0.2 mmol), C6H5–C„CH (40 mg, 0.40 mmol) and CuCl (9 mg, 0.09 mmol) were dissolved in 8 ml pyridine. This solution was stirred for 3 h in air at 60 C. The solvent was removed under reduced pressure. The resulting mixture was washed with saturated NH4Cl solution and extracted with CH2Cl2. The organic phase was incorporated and then dried using the dehydrated MgSO4 and filtrated. The solvent was removed under reduced pressure. The residue was purified by neutral alumina column chromatography using hexane as the eluant. Crystals of L were obtained by recrystallizing solid L from hexane at 15 C. Yield: 28%. m.p. 212–213 C. Anal. Calc. for C26H18Fe: C, 80.83; H, 4.66. Found: C, 80.43; H, 4.70%. IR (KBr disk, cm1) m 815s, 1004m, 1173 m, 1593s, 1521 m, 2146 m, 2208 m, 2852 m, 2924 m, 2960 m. 1H NMR (CDCl3, d): 4.07–4.70 (m, 9H, Fc), 7.26–7.54 (m, 9H, C6H5, C6H4). 13C NMR (CDCl3, d): 66.7–70.0 (Cp), 73.9–82.1 (2C„C), 118.7–141.2 (2Ph). MS (EI) 386 (M+). 3.3. Synthesis of complex [Fc–C6H4–C„C– H][Co2(CO)6] (1)
3.4. Synthesis of complex [Fc–C6H4–(C„C)2– C6H5][Co2(CO)6]2 (2) A benzene solution of Co2(CO)8 (240 mg, 0.70 mmol) and compound L (135 mg, 0.35 mmol) was stirred for 4 h at room temperature. The solvent of the resulting dark mixture was removed in vacuum. The residue was dissolved in a minimal amount of benzene and subjected to chromatographic separation on a silica gel column (2.0 · 40 cm). Elution with hexane afforded a dark band (2). Crystals of 2 were obtained by recrystallizing solid 2 from hexane at 20 C. Complex 2: Yield: 65%. m.p. 164–165 C. Anal. Calc. for C38H18O12Co4Fe: C, 47.60; H, 1.88. Found: C, 47.08; H, 1.85%. IR (KBr disk, cm1) mCO 2013vs, 2054vs, 2084s, 2100s. 1H NMR (CDCl3, d): 4.04–4.67 (m, 9H, Fc), 7.26–7.51 (m, 9H, C6H5, C6H4). 13 C NMR (CDCl3, d): 66.5–69.7 (Cp), 84.4 (C„C), 126.1–139.7 (C6H5, C6H4), 198.5 (CO). MS (ESI): 959 (M++1). 3.5. Synthesis of complex [Fc–C6H4–(C„C)2–C6H4– Fc][Co2(CO)6]2 (3) A benzene solution of Co2(CO)8 (240 mg, 0.70 mmol) and Fc–C6H4–(C„C)2–C6H4-Fc (200 mg, 0.35 mmol) was stirred for 4 h at room temperature. The solvent of the resulting dark mixture was removed in vacuum. The residue was dissolved in a minimal amount of benzene and subjected to chromatographic separation on a silica gel column (2.0 · 40 cm). Elution with hexane afforded a black band (3). Crystals of 3 were obtained by recrystallizing solid 3 from hexane at 20 C. Complex 3: Yield: 69%; m.p. 300 C (dec.). Anal. Calc. for C48H26O12Co4Fe2: C, 50.44; H, 2.28. Found: C, 50.14; H, 2.91%. IR (KBr disk, cm1) mCO 2088vs, 2047vs, 2014s, 2000s. 1H NMR (CDCl3, d): 4.05–4.67 (m, 18H, Fc), 7.26–7.44 (m, 8H, 2C6H4). 13C NMR (CDCl3, d): 66.5–69.7 (Cp), 84.3–99.7 (2C„C), 126.1–139.7 (2C6H4), 198.5 (CO). MS (ESI): 1142 (M+). 3.6. X-ray crystallography of compounds L (2)
A benzene solution of Co2(CO)8 (120 mg, 0.35 mmol) and Fc–C6H4–C„CH (100 mg, 0.35 mmol) was stirred for 4 h at room temperature. The solvent of the resulting dark purple mixture was removed in vacuum. The residue was dissolved in a minimal amount of benzene and subjected to chromatographic separation on a silica gel column (2.0 · 40 cm). Elution with hexane afforded a purple-red band (1). Crystals of 1 were obtained by recrystallizing solid 1 from hexane at 20 C. Complex 1: Yield: 60%. m.p. 132–134 C. Anal. Calc. for C24H14O6Co2Fe: C, 50.35; H, 2.45. Found: C, 49.90; H, 2.47%. IR (KBr disk, cm1) mCO 2013vs, 2054s, 2095s. 1H NMR (CDCl3, d): 4.07–4.65 (m, 9H, Fc), 6.4 (s, 1H, –C„C–H), 7.26–7.43 [m, 4H, C6H4]. 13C NMR (CDCl3, d): 66.6–72.7 (Cp), 90.3, 84.7 (–C„CH), 126.5–139.9 (C6H4), 199.5 (CO). MS (ESI): 572 (M+).
The black crystals of compounds L and 2 were mounted on a glass fibers. All measurements were made on a Bruker SMART APEX CCD diffractometer with graphite mono˚ ) radiation. All data chromated Mo Ka (k = 0.71073 A were collected at 20 C using the / and x scan techniques. All structures were solved by direct methods and expanded using the Fourier technique [26]. An absorption correction based on SADABS was applied [27]. All non-hydrogen atoms were refined by full matrix least-squares on F2. Hydrogen atoms were located and refined by the geometry method. The cell refinement, data collection and reduction were done by Bruker SMART and SAINT [28]. The structure solution and refinement were performed by SHELXSL 97 [29]. The further crystal data and details of measurements are shown in Table 1.
L.-Y. Wang et al. / Polyhedron 26 (2007) 4981–4985
4. Conclusion A new ferrocenylphenyl butadiynyl ligand Fc–C6H4– (C„C)2–C6H5 has been synthesized by the Glaser crosscoupling reaction and three new cobalt coordinated complexes 1, 2, 3 have successfully been obtained by the addition reaction of Co2(CO)6 units to the alkyne bonds of p-ferrocenylphenylacetylene compounds. The synthesis and structure of compounds L and 2 are reported for the first time. The molecular structure of complex 2 shows that the Co2(CO)6 units coordinated to the alkyne bonds are in a trans arrangement. The molecular structure data demonstrate that the butadiynyl groups of ligand L are nearly linear and the coordinated butadiynyl groups in 2 have deviated from a linear structure. Acknowledgements We are grateful to the Specialized Research Fund for the Doctoral Program of Higher Education of China (20060128001) and the Natural Science Foundation of Inner Mongolia for financial support of this work. Appendix A. Supplementary material CCDC 648852 and 648853 contain the supplementary crystallographic data for L and 2. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/ conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@ ccdc.cam.ac.uk. References [1] A. Tarraga, P. Molina, D. Curiel, M.D. Velasco, Organometallics 20 (2001) 2145. [2] R. Dembinski, T. Bartik, B. Bartik, M. Jaeger, J.A. Gladysz, J. Am. Chem. Soc. 122 (2000) 810. [3] (a) J.M. Tour, Chem. Rev. 96 (1996) 537; (b) A.C. Ribou, J.P. Launay, M.L. Sachtleben, H. Li, C.W. Spangler, Inorg. Chem. 35 (1996) 3735.
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Synthesis and structural characterization of new p-ferrocenylphenylacetylene bridged cobalt carbonyl clusters Li-Ying Wang a, Quan-Ling Suo a
a,*
, Li-Min Han a, Yi-Bing Wang a, Lin-Hong Weng
b
Chemical Engineering College, Inner Mongolia University of Technology, Hohhot, 010051, PR China b Department of Chemistry, Fudan University, Shanghai, 200433, PR China Received 3 June 2007; accepted 1 July 2007 Available online 24 August 2007
Abstract A new ferrocenylphenyl butadiynyl compound Fc–C6H4–(C„C)2–C6H5 (L) has been synthesized by the Glaser cross-coupling reaction and three new complexes with a 4-ferrocenylphenyl-l-alkyne-dicobalt moiety, [Fc–C6H4–(C„C)n–R][Co2(CO)6]n 0 [Fc = C5H5FeC5H4, R = H, n = 1, n 0 = 1 (1); R = C6H5, n = 2, n 0 = 2 (2); R = Fc-C6H4, n = 2, n 0 = 2 (3) ], were obtained in the reaction of p-ferrocenylphenylacetylene compounds with Co2(CO)8. Compounds L, 1, 2 and 3 were characterized by elemental analysis, IR, 1 H, 13C NMR and MS. The molecular and crystal structures of compounds L and 2 have been determined by X-ray single crystal analysis. There is a linear C5H4–C6H4–(C„C)2–C6H5 linkage in compound L, and the terminal ferrocenylphenyl and phenyl groups in complex 2 are a cis arrangement. 2007 Elsevier Ltd. All rights reserved. Keywords: Ferrocenylphenyl alkyne; l-Alkyne dicobalt; Molecular structure; Single crystal analysis
1. Introduction Metallic p-conjugated complexes have recently attracted considerable interest due to their physical and chemical properties, leading to potential electrical applications such as molecular wires for the construction of nanoscale electronic devices [1–7]. There has been much research on the coordination of conjugated alkynes to cobalt compounds [8–10]. Many works on the molecular design and synthesis of compounds with two transition metal terminals linked by a p-conjugated system have been published and the electronic communication between the two transition metal end groups has been revealed [11–16]. Compounds with phenyl and alkyne groups can be starting compounds for the synthesis of polynuclear metal complexes because of their reactivity with transition-metal clusters [17,18]. Therefore, studies on the reactions of p-conjugated diynes containing ferrocenyl and phenyl groups with metal carbonyl *
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compounds have continuously appeared [19]. Our group has recently synthesized some p-conjugated compounds with phenyl, biphenyl and ferrocenyl groups and has studied the reactivity of Co2(CO)8 with the unsaturated C„C chain of these compounds [20–22]. Here, we describe the preparation and characterization of the new compounds Fc–C6H4–C„C–C„C–C6H5 (L) and [Fc–C6H4–(C„C)n–R][Co2(CO)6]n 0 [Fc = C5H5FeC5H4, R = H, n = 1, n 0 = 1 (1); R = C6H5, n = 2, n 0 = 2 (2); R = Fc-C6H4, n = 2, n 0 = 2 (3)], and the molecular and crystal structures of compounds L and 2 have been determined by single-crystal X-ray diffraction analysis. To our knowledge, the syntheses and structures of compounds L, 1, 2 and 3 have not been reported previously. 2. Results and discussion 2.1. Synthesis and characterization of compounds L, 1, 2 and 3 The new compound Fc–C6H4–(C„C)2–C6H5 (L) was synthesized by the Glaser cross-coupling reaction [23] of
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Fc–C6H4–C„CH and C6H5–C„CH. Complexes [Fc– C6H4–(C„C)n–R][Co2(CO)6]n 0 [Fc = C5H5FeC5H4, R = H, n = 1, n 0 = 1 (1); R = C6H5, n = 2, n 0 = 2 (2); R = Fc– C6H4, n = 2, n 0 = 2 (3)] were obtained by the reactions of compounds Fc–C6H4–C„CH [24], Fc–C6H4–C„C– C„C–C6H5 (L) and Fc–C6H4–(C„C)2–C6H4–Fc [25] with excess Co2(CO)8, respectively (see Scheme 1). Compound L contains a linear C5H4–C6H4–(C„C)2–C6H5 linkage. One alkyne bond (for 1) or two alkyne bonds (for 2 and 3) coordinate with the Co–Co bonds in complexes 1, 2 and 3. Compound L is an orange yellow, air-stable crystalline compound that is soluble in both non-polar solvents such as benzene and polar solvents such as diethyl ether or chloroform. Complexes 2 and 3 are black, air-stable crystalline compounds, with solubilities similar to compound L. Complex 1 is a purple-black, air-stable crystalline compound, but it is air-sensitive in solution. The absorbing peaks of the FT-IR spectra in the region 2100–2013 cm1 correspond to the stretching vibrations of the coordinated CO groups, which confirm that there are coordinated Co2(CO)6 species. 1H and 13C NMR spectra reflect that there are the appropriate Fc, Ph, C„C and CO groups in L, 1, 2 and 3. The structure and composition of compounds L, 1, 2 and 3 are proven further by their elemental analyses and MS data. 2.2. Molecular structures of compounds L and 2 The crystal and molecular structures of compounds L and 2 were determined by X-ray single crystal analysis. Crystal data and relevant structural parameters are given in Table 1. The structures with the atom numbering schemes are shown in Figs. 1 and 2, and the selected bond lengths and angles are listed in Table 2. The molecule of compound L contains a butadiynyl chain, of which the terminal groups are phenyl and p-ferrocenylphenyl groups (see Fig. 1). The bond distances ˚ ] and C(14)–C(15) [1.195(5) A ˚] C(12)–C(13) [1.198(5) A show there are two C„C triple bonds in L. The shorter ˚ ], C(13)–C(14) [1.370(6) A ˚ ] and C(9)–C(12) [1.436(5) A ˚ ] bond distances, compared to the C(15)–C(16) [1.437(5) A classical single bond length, are the result of electron delo-
C
CH
Table 1 Crystal data and structure refinement for L, 2 Identification code
L
2
Empirical formula Formula weight Temperature (K) ˚) Wavelength (A Crystal system Space group
C26H18Fe 386.25 298(2) 0.71073 triclinic P 1
C38H18O12Co4Fe 958.09 298(2) 0.71073 monoclinic P2(1)/n
7.158(3) 9.875(4) 14.643(6) 76.357(6) 82.288(5) 69.624(5) 941.4(6), 2 1.363 0.807 400 0.15 · 0.15 · 0.10 1.43–26.01 8 6 h 6 8, 12 6 k 6 10, 16 6 l 6 18 4300 3591 (0.0286) 97.2% 0.9236 and 0.8885 3591/0/244 0.987 R1 = 0.0572, wR2 = 0.1102 R1 = 0.0861, wR2 = 0.1186 0.506 and 0.277
19.051(4) 9.6101(19) 22.547(4) 90 113.143(2) 90 3795.7(13), 4 1.677 2.146 1904 0.15 · 0.12 · 0.08 1.19–26.00 22 6 h 6 23, 11 6 k 6 5, 27 6 l 6 27 16 124 7419 (0.0361) 99.4% 0.8470 and 0.7390 7419/0/496 1.237 R1 = 0.0691, wR2 = 0.1463 R1 = 0.0899, wR2 = 0.1534 0.478 and 0.422
Unit cell dimensions ˚) a (A ˚) b (A ˚) c (A a () b () c () ˚ 3), Z Volume (A Calculated density (Mg/m3) Absorption coefficient (mm1) F(0 0, 0) Crystal size (mm) h Range for data collection () Limiting indices
Reflections collected Independent reflections (Rint) Completeness to h Maximum and minimum transmission Data/restraints/parameters Goodness-of-fit on F2 Final R indices [I > 2r(I)] R indices (all data) Largest difference peak and hole ˚ 3) (e A
calization of the C4 diyne chain, phenyl and ferrocenylphenyl units. The data of the bond angles [C(9)–C(12)–C(13), 178.9(4); C(12)–C(13)–C(14), 177.1(4); C(13)–C(14)– C(15), 178.8(4); C(14)–C(15)–C(16), 178.7(4)] demonstrate the carbon chain C(9)C(12)C(13)C(14)C(15)C(16) has a nearly linear structure. The molecule of complex 2 contains two approximately tetrahedral l-alkyne dicobalt moieties bound to the ferr-
Co2(CO)8 equal
Fe
CH
C Fe (CO)3Co
Co(CO)3
1 Co(CO)3
(CO)3Co
_C
C C
_
Co2(CO)8
C
excess
Fe
_C
C C
2
L
(CO)3Co
(CO)3Co
_C C C C Fe
_
Co2(CO)8 Fe
excess
Scheme 1.
C
Fe Co(CO)3
Co(CO)3
_C
C C
3
(CO)3Co
C
Fe
_ Fe
Co(CO)3
L.-Y. Wang et al. / Polyhedron 26 (2007) 4981–4985
Fig. 1. Molecular structure of L.
Fig. 2. Molecular structure of 2.
ocenylphenyl and phenyl units. In 2 the CO ligands coordinated to the Co atoms are terminal (vide IR) and the alkyne bonds adopt the typical l2-g2 coordination fashion, with the alkyne bond lying essentially perpendicular to the Co–Co bond in the C2Co2 units. The Co–Co bond dis˚ , are classical values for tances, in the range 2.452–2.461 A Co–Co bond lengths of similar complexes. The coordi˚; nated alkyne bond lengths of 2 [C(24)–C(25)1.349(7) A ˚ C(26)–C(27)1.355(8) A] are longer than that of L [C(12)– ˚ ) and C(14)–C(15) (1.195(5) A ˚ )] and are C(13) (1.198(5) A similar to the classical alkene bond length due to Co2(CO)6 units coordinated by diyne bonds. In complex 2 the bond
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angle data [C(21)–C(24)–C(25), 140.2(5); C(24)–C(25)– C(26), 141.1(5); C(25)–C(26)–C(27), 141.3(5); C(26)– C(27)–C(28), 144.9(5)] demonstrate the construction of L is altered from a linear to a non-linear structure while L is coordinated to the Co2(CO)6 units. It is noteworthy that the Co2(CO)6 units are coordinated to the alkyne bond in a trans arrangement and the two terminal groups (phenyl and ferrocenylphenyl) are in a cis arrangement (see Fig. 2). Because of the large ferrocenylphenyl substituted group, the molecular structure of 2 is quite different from [Fc–C„C–C„C–C6H5][Co2(CO)6]2 [20]. In L the dihedral angle [1.85(0.28)] between plane 1 [C(22)C(23)C(24)C(25)C(26)] and plane 2 [C(1)C(2)C(3)C(4)C(5)] shows that the two Cp planes in the Fc group are nearly parallel. The dihedral angle [16.15(0.21)] between plane 2 and plane 3 [C(6)C(7)C(8)C(9)C(10)C(11)] is deviated from parallel, and the dihedral angle [74.39(0.13)] between the two phenyl rings, that is plane 3 and plane 4 [C(16)C(17)C(18)C(19)C(20)C(21)], is nearly perpendicular. In 2 the dihedral angle [0.45(0.59)] of the two Cp rings shows that they are nearly parallel. It is interesting that the dihedral angle [9.20(0.47)] between the planes of the Cp ring [C(13)C(14)C(15)C(16)C(17)] and the phenyl ring [C(18)C(19)C(20)C(21)C(22)C(23)] becomes smaller than that of L. The dihedral angle between the two phenyl rings [C(18)C(19)C(20)C(21)C(22)C(23)] and [C(28)C(29)C(30)C(31)C(32)C(33)] alters from 74.39(0.13) to 86.71(0.23). The changes of the dihedral angles in 2 show that the increased steric requirements on the coordinated Co2(CO)6 groups lead to a twisting of the substituents away from each other. 3. Experimental 3.1. General procedures All reactions and manipulations were carried out using standard Schlenk techniques under an atmosphere of pure
Table 2 ˚ ) and angles () for L, 2 Selected bond lengths (A Bond lengths
Bond angles
L C(1)–C(5) C(5)–C(6) C(6)–C(11) C(8)–C(9) C(9)–C(12)
1.432 (5) 1.468(5) 1.390(5) 1.395(5) 1.436(5)
C(12)–C(13) C(13)–C(14) C(14)–C(15) C(15)–C(16) C(16)–C(17)
1.198(5) 1.370(6) 1.195(5) 1.437(5) 1.387(5)
C(3)–C(4)–C(5) C(4)–C(5)–C(6) C(5)–C(6)–C(7) C(8)–C(9)–C(12) C(9)–C(12)–C(13)
2 Co(1)–Co(2) Co(1)–C(24) Co(1)–C(25) Co(2)–C(24) Co(2)–C(25) Co(3)–Co(4) Co(3)–C(26) Co(3)–C(27)
2.452(1) 1.952(5) 1.989(6) 1.975(5) 1.967(5) 2.461(1) 1.963(5) 1.942(6)
Co(4)–C(26) Co(4)–C(27) C(20)–C(21) C(21)–C(24) C(24)–C(25) C(25)–C(26) C(26)–C(27) C(27)–C(28)
1.952(5) 1.968(5) 1.385(8) 1.449(7) 1.349(7) 1.435(8) 1.355(8) 1.463(8)
C(24)–Co(1)–Co(2) C(24)–Co(2)–Co(1) C(25)–Co(1)–Co(2) C(25)–Co(2)–Co(1) C(26)–Co(3)–Co(4) C(26)–Co(4)–Co(3) C(27)–Co(3)–Co(4) C(27)–Co(4)–Co(3)
109.1(4) 127.2(4) 121.4(3) 120.7(4) 178.9(4)
C(12)–C(13)–C(14) C(13)–C(14)–C(15) C(14)–C(15)–C(16) C(16)–C(17)–C(18) C(15)–C(16)–C(21)
177.1(4) 178.8(4) 178.7(4) 120.6(4) 121.4(4)
51.8(2) 51.0(2) 51.3(2) 52.1(2) 50.9(2) 51.3(2) 51.5(2) 50.5(2)
C(15)–C(16)–C(17) C(17)–C(18)–C(19) C(20)–C(21)–C(24) C(21)–C(24)–C(25) C(24)–C(25)–C(26) C(25)–C(26)–C(27) C(26)–C(27)–C(28) C(27)–C(28)–C(29)
108.7(6) 121.1(5) 122.0(5) 140.2(5) 141.1(5) 141.3(5) 144.9(5) 121.5(6)
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nitrogen. Solvents were purified, dried and distilled under a nitrogen atmosphere prior to use. Reactions were monitored by TLC. Chromatographic separations and purifications were performed on 200–300 mesh silica gel. Co2(CO)8 was purchased from Alfa Aesar. The ligands Fc–C6H4– C„CH and Fc–C6H4–(C„C)2–C6H4–Fc were prepared according to the literature methods [24,25]. IR spectra were recorded on a Nicolet FT-IR spectrometer, as KBr discs. Elemental analyses were carried out on an Elementar var III-type analyzer. 1H and 13C NMR spectra in CDCl3 were recorded on a Bruker Avance500 MHz spectrometer. The mass spectra were determined by using a Polaris Q MS, Micromass LCT instrument. Melting points were determined by using XT-4 melting point apparatus. 3.2. Synthesis of compound Fc–C6H4–(C„C)2–C6H5 (L) Fc–C6H4–C„CH (57 mg, 0.2 mmol), C6H5–C„CH (40 mg, 0.40 mmol) and CuCl (9 mg, 0.09 mmol) were dissolved in 8 ml pyridine. This solution was stirred for 3 h in air at 60 C. The solvent was removed under reduced pressure. The resulting mixture was washed with saturated NH4Cl solution and extracted with CH2Cl2. The organic phase was incorporated and then dried using the dehydrated MgSO4 and filtrated. The solvent was removed under reduced pressure. The residue was purified by neutral alumina column chromatography using hexane as the eluant. Crystals of L were obtained by recrystallizing solid L from hexane at 15 C. Yield: 28%. m.p. 212–213 C. Anal. Calc. for C26H18Fe: C, 80.83; H, 4.66. Found: C, 80.43; H, 4.70%. IR (KBr disk, cm1) m 815s, 1004m, 1173 m, 1593s, 1521 m, 2146 m, 2208 m, 2852 m, 2924 m, 2960 m. 1H NMR (CDCl3, d): 4.07–4.70 (m, 9H, Fc), 7.26–7.54 (m, 9H, C6H5, C6H4). 13C NMR (CDCl3, d): 66.7–70.0 (Cp), 73.9–82.1 (2C„C), 118.7–141.2 (2Ph). MS (EI) 386 (M+). 3.3. Synthesis of complex [Fc–C6H4–C„C– H][Co2(CO)6] (1)
3.4. Synthesis of complex [Fc–C6H4–(C„C)2– C6H5][Co2(CO)6]2 (2) A benzene solution of Co2(CO)8 (240 mg, 0.70 mmol) and compound L (135 mg, 0.35 mmol) was stirred for 4 h at room temperature. The solvent of the resulting dark mixture was removed in vacuum. The residue was dissolved in a minimal amount of benzene and subjected to chromatographic separation on a silica gel column (2.0 · 40 cm). Elution with hexane afforded a dark band (2). Crystals of 2 were obtained by recrystallizing solid 2 from hexane at 20 C. Complex 2: Yield: 65%. m.p. 164–165 C. Anal. Calc. for C38H18O12Co4Fe: C, 47.60; H, 1.88. Found: C, 47.08; H, 1.85%. IR (KBr disk, cm1) mCO 2013vs, 2054vs, 2084s, 2100s. 1H NMR (CDCl3, d): 4.04–4.67 (m, 9H, Fc), 7.26–7.51 (m, 9H, C6H5, C6H4). 13 C NMR (CDCl3, d): 66.5–69.7 (Cp), 84.4 (C„C), 126.1–139.7 (C6H5, C6H4), 198.5 (CO). MS (ESI): 959 (M++1). 3.5. Synthesis of complex [Fc–C6H4–(C„C)2–C6H4– Fc][Co2(CO)6]2 (3) A benzene solution of Co2(CO)8 (240 mg, 0.70 mmol) and Fc–C6H4–(C„C)2–C6H4-Fc (200 mg, 0.35 mmol) was stirred for 4 h at room temperature. The solvent of the resulting dark mixture was removed in vacuum. The residue was dissolved in a minimal amount of benzene and subjected to chromatographic separation on a silica gel column (2.0 · 40 cm). Elution with hexane afforded a black band (3). Crystals of 3 were obtained by recrystallizing solid 3 from hexane at 20 C. Complex 3: Yield: 69%; m.p. 300 C (dec.). Anal. Calc. for C48H26O12Co4Fe2: C, 50.44; H, 2.28. Found: C, 50.14; H, 2.91%. IR (KBr disk, cm1) mCO 2088vs, 2047vs, 2014s, 2000s. 1H NMR (CDCl3, d): 4.05–4.67 (m, 18H, Fc), 7.26–7.44 (m, 8H, 2C6H4). 13C NMR (CDCl3, d): 66.5–69.7 (Cp), 84.3–99.7 (2C„C), 126.1–139.7 (2C6H4), 198.5 (CO). MS (ESI): 1142 (M+). 3.6. X-ray crystallography of compounds L (2)
A benzene solution of Co2(CO)8 (120 mg, 0.35 mmol) and Fc–C6H4–C„CH (100 mg, 0.35 mmol) was stirred for 4 h at room temperature. The solvent of the resulting dark purple mixture was removed in vacuum. The residue was dissolved in a minimal amount of benzene and subjected to chromatographic separation on a silica gel column (2.0 · 40 cm). Elution with hexane afforded a purple-red band (1). Crystals of 1 were obtained by recrystallizing solid 1 from hexane at 20 C. Complex 1: Yield: 60%. m.p. 132–134 C. Anal. Calc. for C24H14O6Co2Fe: C, 50.35; H, 2.45. Found: C, 49.90; H, 2.47%. IR (KBr disk, cm1) mCO 2013vs, 2054s, 2095s. 1H NMR (CDCl3, d): 4.07–4.65 (m, 9H, Fc), 6.4 (s, 1H, –C„C–H), 7.26–7.43 [m, 4H, C6H4]. 13C NMR (CDCl3, d): 66.6–72.7 (Cp), 90.3, 84.7 (–C„CH), 126.5–139.9 (C6H4), 199.5 (CO). MS (ESI): 572 (M+).
The black crystals of compounds L and 2 were mounted on a glass fibers. All measurements were made on a Bruker SMART APEX CCD diffractometer with graphite mono˚ ) radiation. All data chromated Mo Ka (k = 0.71073 A were collected at 20 C using the / and x scan techniques. All structures were solved by direct methods and expanded using the Fourier technique [26]. An absorption correction based on SADABS was applied [27]. All non-hydrogen atoms were refined by full matrix least-squares on F2. Hydrogen atoms were located and refined by the geometry method. The cell refinement, data collection and reduction were done by Bruker SMART and SAINT [28]. The structure solution and refinement were performed by SHELXSL 97 [29]. The further crystal data and details of measurements are shown in Table 1.
L.-Y. Wang et al. / Polyhedron 26 (2007) 4981–4985
4. Conclusion A new ferrocenylphenyl butadiynyl ligand Fc–C6H4– (C„C)2–C6H5 has been synthesized by the Glaser crosscoupling reaction and three new cobalt coordinated complexes 1, 2, 3 have successfully been obtained by the addition reaction of Co2(CO)6 units to the alkyne bonds of p-ferrocenylphenylacetylene compounds. The synthesis and structure of compounds L and 2 are reported for the first time. The molecular structure of complex 2 shows that the Co2(CO)6 units coordinated to the alkyne bonds are in a trans arrangement. The molecular structure data demonstrate that the butadiynyl groups of ligand L are nearly linear and the coordinated butadiynyl groups in 2 have deviated from a linear structure. Acknowledgements We are grateful to the Specialized Research Fund for the Doctoral Program of Higher Education of China (20060128001) and the Natural Science Foundation of Inner Mongolia for financial support of this work. Appendix A. Supplementary material CCDC 648852 and 648853 contain the supplementary crystallographic data for L and 2. These data can be obtained free of charge via http://www.ccdc.cam.ac.uk/ conts/retrieving.html, or from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@ ccdc.cam.ac.uk. References [1] A. Tarraga, P. Molina, D. Curiel, M.D. Velasco, Organometallics 20 (2001) 2145. [2] R. Dembinski, T. Bartik, B. Bartik, M. Jaeger, J.A. Gladysz, J. Am. Chem. Soc. 122 (2000) 810. [3] (a) J.M. Tour, Chem. Rev. 96 (1996) 537; (b) A.C. Ribou, J.P. Launay, M.L. Sachtleben, H. Li, C.W. Spangler, Inorg. Chem. 35 (1996) 3735.
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