A New Highly Thermally Stable Co(II)-coordination polymer with Semi-flexible Bis(Imidazole) Directed Secondary Building Unit: Solvothermal Syntheses and Structures

Abstract

A new thermally highly stable 2D coordination polymer, formulated as [Co(μ6-aO2btc)0.5(μ-obix)]n (ao2btc = dioxygenated form of 3,3′,5,5′-azobenzenetetracarboxylate) synthesized using the semi-flexible 1,2-bis(imidazole-1-ylmethyl)benzene (obix) ligand in solvothermal conditions and characterized by single-crystal diffraction, FT-IR and photoluminescence spectroscopy and thermogravimetric/differential thermal analysis. Crystallographic studies of complex 1 reveal that two Co(II) ions are bridged by carboxylate groups of ao2btc ligand to form paddle-wheel SBU. These SBUs are stabilized by the coordination of obix ligand. The Co(II) ions are µ6-bridged by hexadentate aO2btc ligand to generate 2D polymer chains with 3,4-connected binodal net (point symbol {4.62}2{42.62.82}) and topological type is 3,4L13. Thermal analysis shows that complex 1 thermally stable up to 401 °C.