2D extended supramolecular structures via π-π interactions of 1D coordination polymers of cadmium(II) complexes of arylazoimidazole using azido and thiocyanato bridging ligands

Two new one-dimensional polymeric azido- and thiocyanato-bridged cadmium (11) complexes of 1-alkyl-2-(arylazo)imidazoles [RaaiR' (where R = H (a), Me (b); R' = Me (1/3/5), Et (2/4/6)] are described in this work. The ID chain structures of these complexes have been confirmed by X-ray diffraction studies of [Cd(HaaiEt)(N-3)(2)](n) (4a) and [Cd(MeaaiEt)(SCN)(2)](n) (6b). The azide (N-3(-)) acts as end-on (mu-1, 1; EO) and the thiocyanate (SCN-) as end-to-end (mu-1,3; EE) double bridging agents, respectively. The pi-pi interactions amongst inter-chain aromatic-heterocycles generate a uniform sheet. The coordination environment of the cadmium in all these complexes is distorted octahedral. The ligand, RaaiR', is an unsymmetric N,N'-chelator and the distortion in the octahedral geometry is mainly due to the small chelate bite angle. (C) 2004 Elsevier Ltd. All rights reserved.