Synthesis and reaction chemistry of 4-nitrile-substituted NCN-pincer palladium(II) and platinum(II) complexes (NCN = [N [tbnd]C-4-C 6H 2(CH 2NMe 2) 2-2,6] −)

Abstract

Nitrile-functionalized NCN-pincer complexes of type [MBr(N C-4-C 6H 2(CH 2NMe 2) 2-2,6)] ( 6a, M = Pd; 6b, M = Pt) (NCN = [C 6H 2(CH 2NMe 2) 2-2,6] −) are accessible by the reaction of Br-1-N C-4-C 6H 2(CH 2NMe 2) 2-2,6 ( 2b) with [Pd 2(dba) 3 · CHCl 3] ( 5a) (dba = dibenzylidene acetone) and [Pt(tol-4) 2(SEt 2)] 2 ( 5b) (tol = tolyl), respectively. Complex 6b could successfully be converted to the linear coordination polymer {[Pt(N C-4-C 6H 2(CH 2NMe 2) 2-2,6)](ClO 4)} n ( 8) upon its reaction with the organometallic heterobimetallic π-tweezer compound {[Ti](μ-σ,π-C CSiMe 3) 2}AgOClO 3 ( 7) ([Ti] = (η 5-C 5H 4SiMe 3) 2Ti). The structures of 6a (M = Pd) and 6b (M = Pt) in the solid state are reported. In both complexes the d 8-configurated transition metal ions palladium(II) and platinum(II) possess a somewhat distorted square-planar coordination sphere. Coordination number 4 at the group-10 metal atoms M is reached by the coordination of two ortho-substituents Me 2NCH 2, the NCN ipso-carbon atom and the bromide ligand. The N C group is para-positioned with respect to M.