Synthesis, structure and fluorescent properties of CdII, ZnII and NiII complexes with 2-amino-6-methylbenzothiazole and 5-nitroisophthalate as ligands

Abstract

Three new coordination polymers, [M(Ambt)2(Nip)] n (M = Cd for 1 and Zn for 2) and [Ni0.5(Nip)(H2O)2] (HAmbt) (3) (H2Nip = 5-nitroisophthalic acid, Ambt = 2-amino-6-methylbenzothiazole), have been synthesized by hydrothermal methods and are further characterized by X-ray diffraction, IR spectra, elemental analysis, TG-DTA and fluorescence spectra. The structural analyses suggest that 1 and 2 are 1-D chains bridged by Nip anions, in which Ambt is a monodentate ligand and the carboxylate groups of Nip are monodentate and chelating bidentate. Complex 3 consists of two individual fragments, six-coordinate mononuclear NiII and HAmbt cation, in which HAmbts are encapsulated into the concave of the 2-D layer formed by mononuclear units through classic N−H·· · O hydrogen bonds. Abundant hydrogen bond interactions drive the formation of packing structure of the complexes. The three solid complexes display strong emission peaks from intraligand charge transfer similar to free Ambt at room temperature.