Synthesis, structure and thermal properties of polynuclear complexes with a new multidentate ligand, N,N′-bis(5-ethyl-1,3,4-thiadiazol-2-yl)-2,6-pyridinedicarboxamide

Based on N,N′-bis(5-ethyl-1,3,4-thiadiazol-2-yl)-2,6-pyridinedicarboxamide (H2L) and inorganic ZnII and CdII salts, three polynuclear complexes [Zn6(μ4-O)2(L)4] (1), [Zn3(μ3-O)2(L)2(H2L)] (2) and [Cd5(μ3-O)2(L)3(H2L)(CH3OH)(DMF)] (3) have been prepared and their crystal structures have been determined by single-crystal X-ray analysis. The thermal behaviors of these complexes in nitrogen and the thermal decomposition kinetics of complex 2 in the temperature range 350–540 °C have been studied, and kinetic parameters were also obtained. Kinetic results show that the decomposition of complex 2 is double-step reaction: a 1st-order reaction (F1) is followed by an nth-order reaction (Fn).

Graphical abstractThree polynuclear complexes based on N,N′-bis(5-ethyl-1,3,4-thiadiazol-2-yl)-2,6-pyridinedicarboxamide and inorganic ZnII and CdII salts were prepared and their structures were characterized by single-crystal X-ray analysis. The thermal stabilities of all the complexes and the thermal decomposition kinetics of complex 2 have been studied.Figure optionsDownload full-size imageDownload as PowerPoint slide