Synthesis and reaction chemistry of 4-nitrile-substituted NCN-pincer palladium(II) and platinum(II) complexes (NCN = [NC-4-C6H2(CH2NMe2)2-2,6]−)

Abstract

Nitrile-functionalized NCN-pincer complexes of type [MBr(NC-4-C6H2(CH2NMe2)2-2,6)] (6a, M = Pd; 6b, M = Pt) (NCN = [C6H2(CH2NMe2)2-2,6]−) are accessible by the reaction of Br-1-NC-4-C6H2(CH2NMe2)2-2,6 (2b) with [Pd2(dba)3 · CHCl3] (5a) (dba = dibenzylidene acetone) and [Pt(tol-4)2(SEt2)]2 (5b) (tol = tolyl), respectively. Complex 6b could successfully be converted to the linear coordination polymer {[Pt(NC-4-C6H2(CH2NMe2)2-2,6)](ClO4)}n (8) upon its reaction with the organometallic heterobimetallic π-tweezer compound {[Ti](μ-σ,π-CCSiMe3)2}AgOClO3 (7) ([Ti] = (η5-C5H4SiMe3)2Ti). The structures of 6a (M = Pd) and 6b (M = Pt) in the solid state are reported. In both complexes the d8-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 Me2NCH2, the NCN ipso-carbon atom and the bromide ligand. The NC group is para-positioned with respect to M.