Heteroleptic 1D coordination polymers: 5-Coordinated zinc(II) polymer as an efficient transesterification catalyst

Abstract

The synthesis of three 1D coordination polymers (CPs), [Zn(TPPZ)(HCCB)]n·DMF·H2O (1) [Cd(TPPZ)(HCCB)]n(2) and [Co(TPPZ)(HCCB)]n(3), based on the N,N,N-chelating κ3-2,3,5,6-tetrakis(2-pyridyl)pyrazine (TPPZ) and polymerizing carboxylate (–COO−) 3-(carboxy-methylamino)-4-chlorobenzoic acid (H3CCB) ligands, using a solvothermal method, have been described. The CPs have been adequately characterized by satisfactory elemental analyses, FT-IR, UV–vis, emission, TGA and PXRD analysis. The structure of 1 has been verified by single crystal X-ray diffraction analysis. The structural data revealed the 5-coordinated heteroleptic polymeric framework is exclusively extended through the H3CCB carboxylate group and strong N,N,N-chelating TPPZ ligand acts as a branch terminating site. Notably, the structure of 1 is comprised of one unit of each H2O and DMF solvent in its crystal lattice. In contrast, 2 and 3 exclude lattice solvents, as suggested by PXRD studies, after thermal desolvation of 1. Furthermore, 1 with 5-coordinated Zn(II) centers exhibited an efficient catalytic performance for transesterification reactions, with remarkable stability and good reusability. © 2017 Elsevier Ltd