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

• Published in: Polyhedron 2004-06, Vol.23 (10), p.1669-1676
• Main Authors: Chand, Brojogopal, Ray, Umasankar, Mostafa, Golam, Lu, Tian-Huey, Sinha, Chittaranjan
• Format: Article
• Language: English
• Subjects: 1D chain; Arylazoimidazoles; Cadmium(II) complexes; End-on and end-to-end bridging; Sheet structure; X-ray structure
• ISSN: 0277-5387
• DOI: 10.1016/j.poly.2004.02.029

In the title complexes, 1-alkyl-2-(arylazo)imidazoles (RaaiR ′) act as N,N ′ end capping agents and coordination polymers are generated by two double bridging azides (end-on) or thiocyanates (end-to-end) to the Cd centres. The 1D chain structures are confirmed by X-ray diffraction studies. Two new one-dimensional polymeric azido- and thiocyanato-bridged cadmium (II) 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 1D 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 (μ-1,1; EO) and the thiocyanate (SCN −) as end-to-end (μ-1,3; EE) double bridging agents, respectively. The π–π 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.