Conversion of ethyne into methylcarbene and ethene at a di-metal centre: X-ray structure of [Fe₂(CO)₂(µ-CO)(µ-CHMe)(η-C₅H₅)₂]

Abstract

Protonation of the ethyne-derived dimetallocycles [M2(C0) (p-co) Ip-71,73-C(0)C2H2 }(q-C5H5),1 (3% = Fe or Ru) provides cationic vinyl complexes [M,(CO), (p-CO) (p-CHCH,) (+,H5),] [BF,] which, with NaBH,, give bridging methylcarbene complexes [M,(CO),(p-CO) -(p-CHMe)(y-C,H,),] and in the case of ruthenium a n additional ethene complex [Ru,(CO) (p-CO),(C,H,) (7-C5-H,),] ; the structure of cis-[Fe,(CO),(p-CO) (p-CHNle) (q-C,H,),] has been established by X-ray diffraction.

Organic chemistry of dinuclear metal centres. Part 3. µ-Carbene complexes of iron and ruthenium from alkynes viaµ-vinyl cations

“…Me cussed more fully in a forthcoming publication. It is interesting to note that its formation here, by the sequence of H+ and H-addition to (6), which is formed from acetylene, concludes an acetylene to ethylene transformation at a diruthenium centre. No other olefin complex was formed in these syntheses, although propene and but-2-ene analogues of (42) are known.19 The di-iron analogue of (42) exists but is unstable unless held under an atmosphere of ethylene; l9 its nonappearance as a product of treating (13) with NaBH4 is not, therefore, evidence that it is not formed.…”

Organic chemistry of binuclear metal centres. Part 6. µ-Vinylidene and µ-ethylidyne diruthenium complexes: crystal structures of cis-[Ru2(CO)2(µ-CO)(µ-CCH2)(η-C5H5)2] and cis-[Ru2(CO)2(µ-CO)(µ-CMe)(η-C5H5)2][BF4]

“…spectroscopy. -A toluene (100 cm3) solution of [Ru2(CO)(p-CO)(p-C(0)C2HPh)(q-C5H5), J (2) (0.2 g, 0.34 mmol) was heated at reflux for 17 h. Chromatography as above, eluting with (10) 727( 1 Both structures were solved by conventional heavy-atom (Patterson and Fourier) methods, all non-metal atoms, including hydrogens, being located in difference Fourier syntheses. Cyclopentadienyl group hydrogens were constrained to idealised angular geometry, with the C-H distance held fixed at 0.96 A, and assigned a common isotropic thermal parameter.…”

Dinuclear and Polynuclear Ruthenium Non-cluster Compounds

“…57 In hexane, [Ru 3 (CO)i 2 ] reacts with 1,4-dibromocyclooctatetraene to form a related complex, the pale yellow ruthenaindenyl derivative (35; 18%). 58 A probable route to (35) is via the i7 4 -benzocyclobutadiene complex, which was not detected, however. vJt^^Ru(CO) 3 (CO) 3…”

“…Protonation of (12; R = H) gives the orange vinyl complex [RU 2 (JU-CO)O-CH=CH 2 )-(00)2(77-05115)2] + (13); differing orientations of the vinyl group result in the formation of two isomers in solution, both of which are fluxional. 35 Addition of hydride to the /3-vinyl carbon in (13) (by reaction with sodium borohydride) gives a 2:1 mixture of cis-and trans-[R\\2(ii-CO)-(ju-CHMe)(CO)2(? ?-C5H5)2] (14).…”