Syntheses and molecular structures of 18/16-electron half-sandwich iridium(III) complexes with chelating anilido-imine ligands

摘要

A 18-electron complex Cp*IrCl[o-C6H4N(C6H3-Me-p) (CH=NC6H3-Me-p)] (Cp* = eta(5)-pentamethylcyclopentadienyl) (1a) was obtained by the reaction of the lithium salt of o-C6H4N (C6H3-Me-p)(CH=NHC6H3-Me-p) (L-1) with [Cp* IrCl(mu-Cl)](2) in toluene. However, when bulkier ligands (L-2 = o-C6H4N(C6H3-Mep)( CH=NHC6H3-i-Me-2-2,6), L-3 = o-C6H4N(C6H3-Me-p) (CH=NHC6H3-i-Pr-2-2,6)) were employed in the same reaction, two 16-electron complexes {Cp* Ir[o-C6H4N(C6H3-Me-p)(CH=NC6H3-i-Me-2-2,6)]}(+) Cl (2b) and {Cp* Ir[o-C6H4N(C6H3-Me-p)(CH=NC6H3-i-Pr-2-2,6)]}(+) Cl (3b) were formed. A 16-electron complex {Cp* Ir[o-C6H4N(C6H3-Me-p) (CH=NC6H3-Me-p)]}(+) SO3 CF3 (1b) bearing L-1 could be achieved by the reaction of 1a with AgSO3CF3 in CH3CN solution. The molecular structures of 1a and 2b were determined by X-ray crystallography. Theoretical calculations of all the 18/16-electron species were performed to study their bonding characters and electronic properties. Electron donating effect of Cp* and steric effect of anilido-imine ligand were considered as major factors in the formation of coordinative unsaturated complexes 1b, 2b, 3b. (C) 2008 Elsevier B.V. All rights reserved.