Ligand-induced fragmentation of methylnickel phenolates containing a 2-aldehyde function: Structure of (3-tert-butyl-5-methyl-2-oxobenzoyl)-tris(trimethylphosphine)nickel

Article abstract of DOI:10.1021/om00020a009

O-bridging salicylaldehyde derivatives in dimeric methylnickel compounds NiMe(OR)-(PMe₃) showing equilibria of cis and trans forms (OR = 2-oxobenzaldehyde (1), 3-tert-butyl-5-methyl-2-oxobenzaldehyde (2), 3,5-di-tert-butyl-2-oxobenzaldehyde (3), 2-oxonaphthaldehyde (4)) spontaneously undergo, upon addition of trimethylphosphine, a fragmentation reaction forming 2-oxobenzoyl-C,O chelating ligands in 18-electron mononuclear complexes Ni(O?=O)(PMe₃)₃ (O?=O = 2-oxobenzoyl (5), 3-tert-butyl-5-methyl-2-oxobenzoyl (6), 3,5-di-tert-butyl-2-oxobenzoyl (7), 2-oxonaphthoyl (8)). The molecular structure of 6 contains pentacoordinate nickel with a chelate bite angle C-Ni-O = 85.5(1)°. Dissociation of phosphine ligands in 5 gives Ni(O?=O)(PMe₃)₂ (9) and [Ni(O?=O)(PMe₃)]₂ (10), but no mobilization of carbonyl ligands could be observed in the presence of Ni(PMe₃)₄ as CO acceptor.