Vinylidene complexes of transition metals

Use of the MnCC system in organometallic and organic synthesis

“…The ν(CO) for Cp(CO) 2 Re C CHPh (6) (2003, 1938 cm −1 ) are also higher than those for Cp(CO) 2 Re( 2 -PhC CH) (6a) (1980, 1911 cm −1 ) [16]. At the same time, ν(CO) for Cp(CO) 2 Re(L), where L = 1 -vinylidene, 1 -carbene, 2 -alkyne, CO, etc., are 5-20 cm −1 lower as compared with their manganese analogues Cp(CO) 2 Mn(L) [15].…”

“…The unusual manganese complexes obtained by us in 1974 [6] by the interaction of Cp(CO) 2 Mn(thf) with alkynes PhC CGePh 3 , PhC CSnPh 3 and PhC CH (reaction (1)), were at first formulated as compounds of new types with the C 8 H 6 and C 16 H 10 ligands, one of which, Cp(CO) 2 Mn(C 8 H 6 ) (1), was an isomer of -complex Cp(CO) 2 Mn(PhC CH) (1a). These compounds differed greatly from all the cymantrene derivatives known at that time by their bright coloring, stability and spectroscopic characteristics.…”

“…Free Ph(MeCOO)C CH 2 , an unstable liquid, was obtained from PhC CH and MeCOOH in the presence of (MeCOO) 2 Hg/BF 3 ·OEt 2 as catalyst [48]. Scheme The first rhenium vinylidene complex Cp(CO) 2 Re C CHPh (6) was also formed as a result of AVR [16]. Reactions of Cp(CO) 2 Re(thf) with PhC≡CR (R = H, GePh 3 , SnPh 3 ) in the dark gave 2 -alkyne Cp(CO) 2 Re( 2 -PhC CR) (6a-c) and vinylidene complexes 6 and 7 [16b].…”

“…Subsequent addition of a hydrogen atom to the acetylide C 2 atom led to 1 and 6. Consequently, Scheme 2 explained the role of the metal atom M = Mn, Re in the then unprecedented formation of 1 [6,7,15] and 6 [16] from RC CPh and Cp(CO) 2 M(thf) under very mild conditions. At present acetylene-vinylidene rearrangements are known for many mono-and polynuclear systems including the Group 3-10 metals [1-5,41,42, In general, AVR is favorable due to thermodynamic and steric factors.…”

“…Vol'pin, who possessed a wonderful insight, advised us to test our unusual reaction straight away, using different transition metals. Indeed, immediately after Cp(CO) 2 Mn C CHPh (1) and [Cp(CO) 2 Mn] 2 (-C CHPh) (2) [7,15], their rhenium analogues Cp(CO) 2 Re C CHPh and [Cp(CO) 2 Re] 2 (-C CHPh) were obtained from Cp(CO) 2 Re(thf) and PhC CH under the same mild conditions [16].…”