Reductive coupling of alkynes to give ruthenium and osmium clusters of the type M3(1,3-diene)(micro;3-X)(CO)8 containing micro;-eta;2,eta;2- or eta;4-1,3-diene

摘要

Reductive coupling of alkynes to give ruthenium and osmium clusters of the type M3(1,3-diene)(m3-X)(CO)8 containing m-h2,h2- or h4-1,3-diene Shahbano Ali,a Antony J. Deeming,*a Graeme Hogarth,*a Nikesh A. Mehtaa and Jonathan W. Steedb a Department of Chemistry, University College London, 20 Gordon Street, London, UK WC1H 0AJ. E-mail: a.j.deeming@ucl.ac.uk and g.hogarth@ucl.ac.uk b Department of Chemistry, Kingrsquo;s College London, Strand, London, UK WC2R 2LS Received (in Basel, Switzerland) 29th October 1999, Accepted 12th November 1999 Replacement of a CO ligand by MeCN in the capped clusters M3(m-H)2(m3-X)(CO)9 (M = Ru, X = NSO2C6H4Me-4 or M = Os, X = S) allows reductive coupling of alkynes (RCmiddot;CH, R = H or Ph) to give regioselectively the 1,3-diene clusters M3(C4H4R2)(m3-X)(CO)8, with the diene m-h2,h2- coordinated for ruthenium and h4 for osmium.Hydrido clusters usually react with alkynes to give m-s,h2- alkenyl containing clusters.1ndash;3 Dihydrido clusters either give hydridondash;alkenyl compounds1,2 or exceptionally dialkenyl compounds by double insertion.3 Two organyl ligands formed by double insertion could couple to give new organic ligands.More commonly both hydride ligands are delivered to the same organic function leading to simple hydrogenation, for example alkyne to alkene. We now report 1,3-diene-containing clusters formed by double insertion of alkyne into Mndash;H bonds, followed by alkenylndash;alkenyl coupling. Reductive coupling of alkynes to give 1,3-dienes is not very common4 and an alkenylndash;alkenyl coupling mechanism has not been established previously, although alkenyl coupling with other organic ligands has been implicated in Fischerndash;Tropsch synthesis.5 Our approach was to displace CO by more labile MeCN in strongly capped Os3 and Ru3 clusters with two basal hydrido bridges, thereby creating a reactive basal plane of metal atoms within a robust cluster.The cluster Ru3(m-H)2(m3-NR)(CO)9 (R = SO2C6H4Me-4) 1 6 was treated with Me3NOmiddot;2H2O and MeCN to form Ru3(m- H)2(m3-NR)(CO)8(MeCN) 2 with the MeCN ligand cis to the capping atom N; two sharp hydride 1H NMR doublets observed at 225 deg;C are exchange-broadened at 20 deg;C.Treatment of 2 with ButCmiddot;CH gives the mono-insertion product Ru3(m-H)(mtrans- CHNCHBut)(m3-NR)(CO)8 3dagger; reversibly. Compound 3 liberates ButCHNCH2 and Ru3(m3-NR)(CO)10 on treatment with CO at room temperature. In contrast, the less bulky alkynes RCmiddot;CH (R = Ph or H) both react with 2 to give mixtures from which we could isolate two compounds, Ru3(m-h2,h 2- C4H4R2)(m3-NR)(CO)9 4 (R = H) (7) and 5 (R = Ph) (17).Spectradagger; show that 4 and 5 are very similar and 1H NMR spectra for 5 confirm head-to-tail coupling of phenylacetylene to give the trans-1,3-diphenylbutadiene ligand. The single-crystal structure of 4 (Fig. 1)Dagger; shows the presence of m3-NR, m3-CO and m-h2,h2-s-cis-butadiene. While m-h2,h2-s-cis-1,3-diene is known in several cases,7 m-h2,h2-s-trans-butadiene,8 m-h1,h3-scis- butadiene9 and m-h1,h4-s-cis-1,3-diene10 are also known.The cluster Os3(CO)10(m-C4H6) contains m-h2,h2-s-transbutadiene. 11 Intermediate alkenyl complexes were not observed in the formation of 4 and 5, although the formation of 3 suggests that they are involved. The Os analogue of 2 only reacts with alkynes to give clusters related to 3, without diene formation. However, the cluster Os3(m-H)2(m3-S)(CO)8(MeCN) 6, formed as for 2, was treated with PhCmiddot;CH in refluxing THF for 24 h to give various insertion products: Os3(m-H)(m- PhCNCH2)(m3-S)(CO)8 7 (23), Os3(m-H)(m-CHNCHPh)(m3- S)(CO)8 8 (11), Os3(m-PhC2H2)2(m3-S)(CO)7 9 (17) and Os3(h4-PhCHNCHCPhNCH2)(m3-S)(CO)8 10 (12).The isomeric mono-insertion products 7 and 8 were shown by 1H NMR to be non-interconverting regioisomers. The di-insertion product 9 exists as a mixture of isomers (1H NMR evidence) with both CPhNCH2 and CHNCHPh ligands present.The 1,3-diphenylbutadiene complex 10 from treatment of 6 with PhCmiddot;CH is also formed by treating the dialkenyl cluster 9 with CO. 1H NMR data for 10 confirm head-to-tail alkyne coupling but there are very different chemical shifts for the four vinylic hydrogen atoms in 10 compared with those for 5 (d 1.55, 2.43, 3.58 and 6.79 for 10 cf. d 2.98, 4.72, 5.53 and 5.82 for 5). Fig. 1 Thermal ellipsoid drawing (30 probability) of Ru3(m-h2,h2- C4H6)(m3-NSO2C6H4Me-4)(CO)8 4 with the tosyl group omitted.Selected lengths (Aring;) and angles (deg;): Ru(1)ndash;Ru(2) 2.7560(3), Ru(1)ndash;Ru(3) 2.7416(4), Ru(2)ndash;Ru(3) 2.7554(3), Ru(1)ndash;C(9) 2.258(3), Ru(1)ndash;C(10) 2.304(3), Ru(2)ndash;C(11) 2.338(3), Ru(2)ndash;C(12) 2.246(3), C(9)ndash;C(10) 1.393(5), C(10)ndash; C(11) 1.461(4), C(11)ndash;C(12) 1.393(5); C(9)ndash;C(10)ndash;C(11) 127.5(3), C(10)ndash; C(11)ndash;C(12) 127.6(3). This journal is copy; The Royal Society of Chemistry 1999 Chem. Commun., 1999, 2541ndash;2542 2541Furthermore there is no IR evidence for m3-CO in 10.A singlecrystal structure determination (Fig. 2)Dagger; confirms that 10 has a different structure from that of 4 or 5. Indeed there is no m3-CO in 10, but instead the two CO ligands at Os(1) are semibridging to Os(2) and Os(3) respectively. More importantly the 1,3-diene is h4-co-ordinated to Os(1) rather than bridging as in 4. The formation of 1,3-diene-containing clusters from simple alkynes is unique. The mono-insertion compounds M3(m-H)(malkenyl)( m3-X)(CO)8 appear to be more reactive towards further alkyne insertion into the second Mndash;H bond than towards reductive elimination of alkene.This almost certainly results from the ligands being along separate Mndash;M edges and indicates that hydrogenation reactions induced by clusters could be very different from those catalysed by mononuclear compounds. The formation of m-h2,h2-diene for Ru and h4-diene for Os may reflect different alkenylndash;alkenyl coupling mechanisms. We are attempting to establish the structures of the isomeric dialkenyl compounds and the geometric details of the alkenylndash;alkenyl coupling.Notes and references dagger; Selected spectroscopic data (IR for light petroleum solutions, 1H NMR in CDCl3, 400 MHz, 25 deg;C, unless stated otherwise; aryl and tosyl signals omitted). 2: n(CO)/cm21 (CH2Cl2) 2092m, 2065s, 2057s, 2013s, br; 1H NMR (225 deg;C, 500 MHz): d 222.37 (d, J 2.5 Hz), 216.63 (d, J 2.5 Hz), 2.32 (s, MeCN); 3: n(CO)/cm21 (CH2Cl2) 2105m, 2074s, 2040s, 1984m; 1H NMR (300 MHz) d 213.64 (s), 1.22 (s, But), 6.17 (d, J 12.2 Hz, CHNCHBut), 9.82 (d, J 12.2 Hz, CHNCHBut); 4: n(CO)/cm21 2093s, 2054s, 2044s, 2029m, 2019m, 2006m, 1990w, 1758w, br; 1H NMR (300 MHz) AAABBACCA spectrum for C4H6: d 2.91 (d, J 13.4 Hz), 3.98 (d, J 9.5 Hz), 4.58 (m); 5: n(CO)/cm21 2090s, 2083m (sh), 2053s, 2043s, 2027m, 2018m, 2010m, 2004w, 1997w, 1990w, 1960w, 1948w 1752m, br; 1H NMR (300 MHz) d 2.98 (d, J 1.0 Hz), 4.72 (s), 5.53 (d, J 13.5 Hz), 5.82 (dd, J 1.5, 13.4 Hz); 6: n(CO)/cm21 (CH2Cl2) 2121w, 2085m, 2049s, 1996s, br; 1H NMR d224.69 (s), 219.65 (d, J 1.2 Hz), 2.54 (s, MeCN); 7: n(CO)/cm21 2097m, 2063s, 2037s, 2022m, 2013s, 2000m, 1990w, 1980m; 1H NMR d 213.52 (s), 4.29 (d, J 1.4 Hz), 4.59 (d, J 1.4 Hz); 8: n(CO)/cm21 2099m, 2067s, 2035s, 2022m (sh), 2017s, 2004w, 1992w, 1978m; 1H NMR d 214.07 (s), 5.91 (d, J 11.6 Hz, CHNCHPh), 9.46 (d, J 11.6 Hz, CHNCHPh); 9: n(CO)/ cm21 2077m, 2044s, 2026, 2013s, 2009s, 1980ms, 1969w; 10: n(CO)/cm21 2082m, 2049s, 2025m, 2006s, 1996m, 1979m, 1963w, 1918w; 1H NMR d 1.55 (d, J 3.5 Hz), 2.43 (d, J 3.4 Hz), 3.58, (d, J 9.1 Hz), 6.79 (d, J 9.0 Hz).Dagger; Crystal data: for 4: C19H13NO10Ru3S, M = 750.57, orthorhombic, space group Pbc21, a = 10.3720(2), b = 13.5883(2), c = 16.0282(3) Aring;, V = 2258.98(7) Aring;3, Z = 4, Dc = 2.207 g cm23, l(Mo-Ka) = 0.71073 Aring;, m = 2.129 mm21, F(000) = 1448. 4203 independent reflections were measured in the q range 3.80ndash;26.00deg; for a yellow crystal in an oil droplet solidifed at T = 100(2) K. 309 parameters were refined to give R (all data) = 0.0180 and wR2 (all data) = 0.0456. The Nonius lsquo;Collectrsquo; program was used for indexing and data collection. The structure was solved by direct methods and refined (SHELXL-97) with all non-hydrogen atoms anisotropic and with hydrogen atoms included using a riding model. For 10: C24H14O8Os3S, M = 1033.01, triclinic, space group P�1, a = 9.406(2), b = 10.615(2), c = 13.885(3) Aring;, a = 91.58(3), b = 108.82(3),g = 104.51(3)deg;, V = 1261.4(5) Aring;3, Z = 2, Dc = 2.720 g cm23, l(Mo-Ka) = 0.71073 Aring;, m = 15.201 mm21, F(000) = 932. 4421 independent reflections were measured at room temperature in the q range 2.65ndash;25.05deg;. 325 parameters were refined to give R (all data) = 0.0564 and wR2 (all data) = 0.1453. The structure was solved by direct methods and refined (SHELXL-97) with all non-hydrogen atoms anisotropic and with hydrogen atoms included using a riding model.CCDC 182/1484. See http:// www.rsc.org/suppdata/cc/1999/2541/ for crystallographic files in .cif format. 1 A. J. Deeming, S. Hasso and M. Underhill, J. Organomet. Chem., 1974, 80, C53; J. Chem. Soc., Dalton Trans., 1975, 1614. 2 S. C. Brown and J. Evans, J. Chem. Soc., Dalton Trans., 1982, 1049; D. H. Hamilton and J. R. Shapley, Organometallics, 1998, 17, 3087; M. Koike, D. H. Hamilton, S. R. Wilson and J. R. Shapley, Organometallics, 1996, 15, 4930. 3 H. Chen, B.F. G. Johnson, J. Lewis and P. R. Raithby, J. Organomet. Chem., 1989, 376, C7. 4 N. Satyanarayana and M. Periasamy, Tetrahedron Lett., 1986, 27, 6253; S. A. Rao and M. Periasamy, J. Chem. Soc., Chem. Commun., 1987, 495; I. Ryu, N. Kusumato, A. Ogawa, N. Kambe and N. Sonoda, Organometallics, 1989, 8, 2279; M. I. Bruce, G. A. Koutsantonis, E. R. T. Tiekink and B. K. Nicholson, J. Organomet. Chem., 1991, 420, 271; K. Tani, K. Ueda, K. Arimitsu, T. Yamagata and Y. Kataoka, J. Organomet.Chem., 1998, 560, 253. 5 P. M. Maitlis, H. C. Long, R. Quyoum, M. L. Turner and Z.-Q. Wang, Chem. Commun., 1996, 1. 6 Prepared by reaction of Ru3(CO)12 with 4-MeC6H4SO2NH2. 7 Y. Kaneko, T. Suzuki and K. Isobe, Organometallics, 1998, 17, 996; J. A. King, Jr and K. P. C. Vollhardt, Organometallics, 1983, 2, 684. 8 V. C. Adams, J. A. J. Jarvis, B. T. Kilbourn and P. G. Owston, Chem. Commun., 1971, 467; T. Murahashi, N. Kanehisa, Y. Kai, T. Otani and H. Kurosawa, Chem. Commun., 1996, 825. 9 A. Scholz, A. Smola, J. Scholz, J. Loebel, H. Schumann and K.-H. Thiele, Angew. Chem., Int. Ed. Engl., 1991, 30, 435. 10 J. T. Barry, J. C. Bollinger, M. H. Chisholm, K. C. Glasgow, J. C. Huffman, E. A. Lucas, E. B. Lubkovsky and W. E. Streib, Organometallics, 1999, 18, 2300. 11 M. Tachikawa, J. R. Shapley, R. C. Haltiwanger and C. G. Pierpont, J. Am. Chem. Soc., 1976, 98, 4651. Communication 9/08706K Scheme 1 Reagents and conditions: i, Me3NOmiddot;2H2O, MeCN, CH2Cl2, 293 K, 30 min; ii, PhC2H, THF, 293 K, 24 h; iii, PhC2H; iv, CO. Fig. 2 Thermal ellipsoid drawing (30 probability) of Os3(h4- PhCHNCHCPhNCH2)(m3-S)(CO)8 10. Selected lengths (Aring;) and angles (deg;): Os(1)ndash;Os(2) 2.8696(12), Os(1)ndash;Os(3) 2.8524(10), Os(2)ndash;Os(3) 2.7339(9), Os(1)ndash;C(1) 2.214(13), Os(1)ndash;C(2) 2.252(12), Os(1)ndash;C(3) 2.252(12), Os(1)ndash;C(4) 2.267(12), C(1)ndash;C(2) 1.40(2), C(2)ndash;C(3) 1.44(2), C(3)ndash;C(4) 1.46(2); C(1)ndash;C(2)ndash;C(3) 116.9(12), C(2)ndash;C(3)ndash;C(4) 118.0(12). 2542 Chem. Commun., 1999, 2541ndash;25