Half-way coordination state of a butadienyl group on ruthenium. η3-Allylic bonding with η1-character or vice versa
摘要:
The butadienyl complexes formed by the reaction of trans-(R1)CH = CHC = CR2 (R1, R2 = SiMe3, (t)Bu, Me, Et) with RuCl(CO)H(PPh3)3 exhibit unique structures: instead of taking the 18-electron configuration of the metal by conventional eta(3)-coordination of the butadienyl ligand, they shift significantly to the 16-electron eta(1)-coordination state.
Stoichiometric and catalytic reaction of Ru(II) phosphine complexes with alkynes, olefins, and enynes are described. The hydride complex RuCl(CO)H(PPh3)3 (1) reacts with the double bond of a cis-enyne whereas it reacts with triple bonds of trans-enynes. Metathesis of vinyl silanes with olefins are catalyzed by 1 where β-Si elimination is the key step. Dimerizations of tBu- and Me3Si-substituted acetylanes