Metal complexes of an N-selenocarbamoyl benzamidine

The N-selenocarbamoyl benzamidine 4-MeC6H4N(H)C(Ph)=NC(Se)NEt2 (HL) was prepared from the reaction of the corresponding isoselenocyanate with Et2NH. The reactivity of HL with various metal compounds including [Ni(OAc)(2)], [PdCl2((t)Bu(2)bipy)], H[AuCl4], [AuCl(SMe2)] as well as the cyclometallated species [Pd(OAc)(kappa C,N-C6H4N(Me)N=O)](2) was studied. In the case of the Ni(II) and Pd(II) compounds, square planar bis(chelate) complexes were formed in which the deprotonated N-selenocarbamoyl benzamidine acts as a monoanionic [Se,N](-) ligand. Reaction of the gold(III) precursor with two equivalents of HL, resulted in reduction and formation of the gold(I) complex [AuCl(HL)], in which the neutral N-selenocarbamoyl benzamidine coordinates to the metal only via the selenium atom. The same coordination mode of the N-selenocarbamoyl benzamidine is observed in the gold(I) salt [Au(HL)(2)]Cl. Both these complexes are also accessible from the reaction of [AuCl(SMe2)] with one or two equivalents of HL The electronic structure of the ligand was studied using computational methods. (C) 2011 Elsevier Ltd. All rights reserved.