Syntheses, Structures and Properties of Co(II) and Co(II)/Zn(II) Coordination Polymers Based on Flexible Tris(imidazole) and Multicarboxylate Ligands

Abstract

Two coordination polymers, namely, Co(BPDA)(titmb)·3H2O (1) and CoZn(BTC)(titmb)Br (2) (titmb = 1,3,5-tris(1-imidazol-1-ylmethyl)-2,4,6-trimethylbenzene, H2BPDA = 4,4′-carbonyldibenzoic acid and H3BTC = 1,3,5-benzenetricarboxylic acid), have been synthesized and characterized by elemental analyses, infrared spectra (IR), thermogravimetric analyses (TGA) and single-crystal X-ray diffraction. Single crystal structure analysis shows that complex 1 exhibits a three-dimensional (3D) twofold interpenetrating architecture with a very rare (3,5)-connected fsc-3,5-Cmce-2 topology, while complex 2 features an interesting three-dimensional (3D) (3,6)-connected framework by self-penetration of two sets of (10,3)-a nets with an unprecedented (63)2(612 ·83) topology. The results reveal that the carboxylic building blocks play a significant role in promoting the diversity of the observed structural motifs. Two complexes indicate high thermal stabilities. The emission in the blue region indicates that complexes 1 and 2 appear to be good candidate for a promising blue-light-emitting materials. Moreover, complex 1 has also modest power SHG activity. The two complexes with unique topology have been constructed by two different multicarboxylates and metal salts with the flexible titmb ligand. The results reveal that the carboxylic building blocks play a significant role in promoting the diversity of the observed structural motifs.