2167
Organometallics 1995, 14, 2167-2169
A Triosmium Cluster with a Novel Mode of Metallacyclopentadiene Fragment Bonding. X-ray Structure and Reactivity of Os~(p3-9 l:ql:q2:q2-C (SiMes)C(Me)C(H)C(Ph)}(C0)s Avth'andil A. Koridze," Nadezhda M. Astakhova, Fedor M. Dolgushin, Aleksandr I. Yanovsky, Yuri T. Struchkov, and Pave1 V. Petrovskii Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, Moscow 117813, Russian Federation Received November 1, 1994@ Summary: The molecular structure of Os3@3-~f:7~:$:$C(SiMedC(Me)C(H)C(Ph)}(CO)g (3), obtained from Os& Me3SiC2Me)(1c-CO)(CO)g(2)and PhCECH in hot hexane, involves a n osmacyclopentadiene ring n-coordinated to the remaining two osmium atoms of the cluster. Heating of 3 in refluxing benzene yields two new compounds, 0.93(p -H)bgC(SiMed C(Me)C(H)C(C&I~)}(CO)S(4) with a A B rearranged, coordinated on one cluster edge osmacycloFigure 1. Two possible structures for O S ~ ( C ~ R ~ ) ( C O ) ~ pentadiene fragment, and O~z(1c-rl:rl:77~-C(SiMedC-complexes. (Me)C(H)C(Ph)}(C0)6(5). Compound 4 reacts with PPh3 at room temperature to form Os3{1c-r1:r1:r4-C(SiMedCScheme 1 (Me)C(H)C(Ph)>(CO)shd(8). Me3Si \ Me It is well-known1 that all triosmium clusters with C=c' osmacyclopentadiene fragments characterized thus far 10s-0shave the structure of the B type (Figure 11,and although ' \ / \ PhcECH * the alternative structure A had been suggested earlierla for Os3(C4Phd(CO)g(11,it has never been proved. Later, 2 it was shown by an X-ray diffraction study2 that this complex has the structure B, 0~3@-77~:r':r~-C4Phq)(CO)g. It may be noted, however, that p3-)71:r71:r2:772coordination of an organic fragment to a triangular array of osmium atoms has been found for the cluster os3+ + { C(Me)C(Me)C(O)C(Me)C(Me)}(CO)s{P(OMe)3} with an osmacyclohexadienone ring.3 SiMe3 In the course of our study of silylalkyne transformations on triruthenium and triosmium clusters4 we 3 4 obtained and fully characterized a triosmium cluster of the structure A, OS~CU~-~~:~':~~:~;~~-C(S~M~~)C(M~)C(H)C(Ph)}(CO)g(3). Reaction of the alkyne complex Os3@3-Me3SiC2Me)@-CO)(CO)g(2) with phenylacetylene in hot hexane yields the red compound 3 in 65% yield (Scheme 1). #--\ SiMe3 I
't r 'Ikf - '
n
~~
Abstract published in Advance ACS Abstracts, February 15,1995. (1)(a) Gambino, 0.; Vaglio, G. A.; Ferrari, R. P.; Cetini, G . J . Organomet. Chem. 1971, 30, 381. (b) Gambino, 0.; Ferrari, R. P.; Chinone, M.; Vaglio, G. A. Inorg. Chim. Acta 1975,12,155. (c)Ferrari, R. P.; Vaglio, G. A,; Gambino, 0.; Valle, M.; Cetini, G. J. Chem. Soc., Dalton Trans. 1972, 1998. (d) Deeming, A. J.; Hasso, S.; Underhill, M. J. Chem. SOC.,Dalton Trans. 1975, 1614. (e) Tachikawa, M.; Shapley, J. R.; Pierpont, C. G. J. Am. Chem. SOC.1975,97, 7172. (D Johnson, B. F. G.; Khattar, R.; Lahoz, F. J.; Lewis, J.; Raithby, P. R. J . Organomet. Chem. 1987,319, C51. (2) Ferraris, G.; Gervasio, G. J. Chem. Soc., Dalton Trans. 1974, 1813. (3) Johnson, B. F. G.; Khattar, R.; Lewis, J.; Raithby, P. R.; Smit, D. N. J. Chem. Soc., Dalton Trans. 1988, 1421. (4) (a)Koridze, A. A.; Astakhova, N. M.; Yanovsky, A. I.; Struchkov, Yu. T. Metalloorg. Khim. 1992,5,886. (b) Yanovsky, A. I.; Struchkov, Yu. T.; Astakhova, N. M.; Koridze, A. A. Metalloorg. Khim. 1990, 3, 704. (c) Koridze, A. A.; Astakhova, N. M.; Dolgushin, F. M.; Yanovsky, A. I.; Struchkov, Yu. T. Izv. Akad. Nauk, Ser. Khrm. 1993, 2011. (d) Koridze, A. A,; Astakhova, N. M.; Petrovskii, P. V.; Dolgushin, F. M.; Yanovsky, A. I.; Struchkov, Yu. T. J . Organomet. Chem. 1994, 481, 247.
5
6
@
Compound 3 was characterized by IR and 'H NMR spectra and elemental a n a l y ~ i s .The ~ IR spectrum of 3 is distinctly different from that of 1 and related osmium with side-on-coorcomplexes Os3@3-y1:r1:r4-C4R4)(CO)g dinated osmacyclopentadiene.la-e The X-ray diffraction study6 of compound 3 has shown that this complex represents a triosmium cluster involving the osmacyclopentadiene moiety (Figure 2). In contrast to all previously structurally characterized trimetal clusters with metallacyclopentadiene frag(5) Compound 3 is air-stable and was isolated by TLC on silica gel using a 1:9 benzene/petroleum ether (40-70 "C) solvent mixture. IR (v(CO),cm-'; in hexane): 2085 (m), 2049 (vs), 2026 (w),2011 (s),1996 (w), 1984 (m). 'H NMR ( 6 ;in c&): 7.06-7.40 (m, 5H), 5.69 (s, 1H), 2.14 (s, 3H), 0.34 (s, 9H). Anal. Calcd (found): C, 26.63 (26.39); H, 1.75 (1.66); OS, 55.02 (55.36); Si, 2.71 (2.71).
0276-733319512314-2167$09.00/00 1995 American Chemical Society
Communications
2168 Organometallics, Vol. 14, No. 5, 1995 0111
014)
018)
Figure 2. Molecular structure of O S ~ ~ L ~ - ~ ~ : ~ ~ : ~ ~ : ~ ~ - C ( S ~ M ~ ~ ) C ((3). M ~ Open ) C ( Hbonds ) C ( Pcorrespond ~ ) } ( C O to ) ~x coordination. Selected interatomic distances (A) are as follows: Os(l)-Os(2) = 2.811(1), Os(l)-Os(3) = 2.811(1), Os(2)Os(3) = 2.825(1), Os(l)-C(lO) = 2.19(1), O~(l)-C(13)= 2.12(1), Os(2)-C(10) = 2.18(1), OS(2)-C(ll) = 2.42(2), Os(3)C(12) = 2.25(1), 0~(3)-C(13)= 2.22(1), C(lO)-C(ll) = 1.44(2), C(ll)-C(12) = 1.46(2),C(12)-C(13) = 1.48(2). ments, the hydrocarbon ligand in 3 is directly bonded to all three metal atoms, its two double bonds being coordinated by two different Os atoms, each of them bearing three terminal carbonyl groups-ie., 3 has a structure of type A. The osmacyclopentadiene ring has an envelope conformation, its folding angle along the C(lOW(13) line being equal to 28.8". The Os(1) atom is displaced from the C(lO)C(ll)C(12)C(13)group, which is planar within 0.02 A, by 0.794 A; the other osmium atoms 0 4 2 ) and Os(3) are displaced from this plane in the same direction as Os(1) by 2.133 and 2.093 A, respectively. In spite of the apparent symmetry of the central nucleus of the cluster involving the Os3 triangle and osmacyclopentadiene ring, some geometrical parameters show considerable differences between both wings of the complex evidently caused by the different substituents at the carbon atoms of the osmacyclopentadienemoiety. Thus, one of the n bonds is characterized by distinctly nonequivalent Os-C bonding distances (Os(2)-C(lO) = 2.18(1) A and Os(2)-C(ll) = 2.42(2) A), whereas another n bond exhibits a quite normal symmetrical mode of coordination (Os(3)-C(12) = 2.25(1)A and Os(6) Red crystals of 3 were grown from hexane at -5 "C. Crystal data for 3: C ~ ~ H I ~ O ~MO, S = ~1037.1, S ~ , monoclinic, space group P21/ c, at 296 K, a = 8.996(3)A, b = 13.450(5) A, c = 22.082(9) A, /3 = 93.88(3)",V = 2669(2) A3, Dealed= 2.580 g/cm3for 2 = 4. Intensities of 5614 independent reflections and cell parameters were measured a t 296 K with a Siemens P3PC automated difiactometer using Mo Ka radiation ( I = 0.710 73 A, graphite monochromator, 8/28 scan, 8 5 27", semiempirical absorption correction on the basis of q scans, minimum transmission factor 0.4142). The structure was solved by direct methods and refined by the least-squares technique in the anisotropic approximation. H atoms were placed geometrically and included in the structure factor calculation in the riding motion approximation with the common refined U,,,= 0.07(2) Az. The refinement of 326 parameters against 4539 reflections with I > 3a(I) converged at R = 0.0593 and R, = 0.0705. All calculations were carried out with an IBM PC AT computer using the SHELXTL PC program p a ~ k a g e . ~ (7) Robinson, W.; Sheldrick, G . M. SHELX. In Crystallographic ComputingTechniques and New Technologies; Isaacs, N. W., Taylor, M. R., Eds.; Oxford University Press: Oxford, England, 1988; p 366.
(3)-C(13) = 2.22(1) A). A noticeable difference is also observed between the metal-carbon u bonds within the osmacyclopentadiene ring (Os(l)-C(lO) = 2.19(1) A and Os(l)-C(13) = 2.12(2) A). Other products obtained in the reaction of 1 with phenylacetylene are yellow O S ~ @ - H ) { ~ ~ - C ( S ~ M ~ ~ ) C (Me)C(H)C(CsH4)}(CO)8(4; 8% yield), colorless Osz{prl1:rl1:rl4-C(SiMe3)C(Me)C(H)C(Ph)}(CO)6 (5; 12%yield), and amethyst-violet OS~@-)~~:V~:V~-C(S~M~)~C(M (Ph)C(H)}(CO)g(6;5%yield). All three compounds were characterized by lH NMR and IR spectra.8 The lH NMR spectrum of compound 6 shows a single proton resonance in the substantially low-field region at 6 7.93 ppm, which is characteristic for hydrogen atoms at the u,n-coordinated carbons. This feature allows to assign to complex 6 the structure shown in Scheme 1. The similarities in the shielding of Measi, Me, and H substituents of the osmacyclopentadiene ring in the 'H NMR spectra of compounds 3-5 suggest that the last two complexes are derived from 3. Indeed, when 3 was heated in refluxing benzene, 4 and 5 were formed in the ratio 1:1.6. Although the yellow hydride 4 does not react with CO with formation of O S ~ @ - ) ~ ~ : ~ ~ : V ~ - C (SiMe3)C(Me)C(H)C(Ph)}(CO)g (7) (in contrast to the (8) Compounds 4-6 are isolated by TLC on silica gel using a 1:10 benzendpetroleum ether (40-70 "C) solvent mixture. IR ( ~ ( c o )cm-'; , in hexane): for 4,2095 (s), 2055 (s), 2029 (vs), 2017 (s), 2012 (m), 1995 (m), 1985 (m), 1972 (m); for 5, 2080 (s), 2049 (vs), 2010 (S), 2000 (VS), 1979 (s), 1968 (s); for 6, 2108 (m), 2053 (VI), 2035 (m), 2030 (SI, 2011 (vs), 1994 (m), 1982 (m), 1936 (m). IH NMR (6; in CsDs): for 4, 6.98.0 (m, 4H), 6.11 (s, lH), 2.29 (s, 3H), 0.34 (8,9H), -14.76 (6,1H); for 5, 6.98-7.21 (m, 5H), 6.28 (s, lH), 2.15 (s, 3H), 0.33 (s, 9H); for 6 , 7 . 9 3 (s, iH), 7.06-7.20 (m, 5H), 2.30 (s, 3H), 0.50 (8, 9H). Sat1sfactOT elemental analyses (C, H) have been obtained for 4-6. (9)Compound 8 was isolated by TLC on silica gel using a 1:4 benzendpetroleum ether (40-70 "C) solvent mixture. IR in hexane solvent (v(CO),cm-'): 2069 (m), 2038 (s), 1995 (vs), 1980 (vs), 1965 (s), 1915 (m). lH NMR (CeDe; 6): 6.99-7.77 (m, 20H), 6.80 (6, 1H), 2.47 (8, 3H), 0.66 (s,9H). Anal. Calcd (found): C, 37.79 (37.85);H, 2.62 (2.76).
Organometallics, Vol. 14, NO.5, 1995 2169
Communications
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Me
H
3
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It still remains unclear whether the observed 3 4 transformation involves the decarbonylation of complex 3 with subsequent face-on side-on rearrangement accompanied by the ortho metalation of the phenyl group or, alternatively, this reaction proceeds through the formation of complex 7, the unstable intermediate with side-on osmacyclopentadiene coordination.
Scheme 2
4
SiMe3
a
related compound Os301-H)013-C4Ph3CsH4)(co)8, which adds CO instantaneouslyla to yield l),it slowly reacts with PPh3 a t room temperature to give the phosphine derivative of 7,uiz., the violet-black compound os3@q1:q1:q4-C(SiMe3)C(Me)C(H)C(Ph)}(CO)dPPh3) (8;85% yield)g (Scheme 2).
Acknowledgment, We are indebted t o Dr. M. G. Ezernitskaya for recording of the IR spectra and helpful discussion. This work was supported by the Russian Foundation of Fundamental Research (Grant Nos. 94and the International Sci03-08167and 94-03-08338) ence Foundation (Grant No. MO 4000). A.I.Y. is pleased to thank the American Crystallographic Association for financial support within the framework of the ACAI USNCCr grants program. Supplementary Material Available: Tables giving the structure determination summary, positional and thermal parameters, and bond distances and angles for 3 (8 pages). Ordering information is given on any current masthead page. OM9408324
