A Zn(II)-COORDINATION POLYMER FORMED BY BENZOATE AND 3-PYRIDINEMETHANOL LIGANDS: SYNTHESIS, SPECTROSCOPIC PROPERTIES, CRYSTAL STRUCTURE AND KINETICS OF THERMAL DECOMPOSITION

摘要

The complex catena-poly[bis(benzoato-O)-bis(3-pyridinemethanol-N,O)-zinc(II)], [Zn(benz)_2(3-pymeth)_2]_n was prepared and characterised by elemental analysis, IR spectroscopy, thermal analysis and an X-ray structure determination. Zinc is octahedrally coordinated. Two coordination sites are occupied by oxygen atoms of two monodentate benzoate groups, two by the nitrogen atoms of 3-pyridinemethanol, and two by methanolic oxygen atoms of 3-pyridinemethanol from neighbouring structural units. Due to the bridging 3-pyridine-methanol ligand, molecules of the complex are connected into infinite chains along the c axis. The bridging function is reflected in the IR spectrum by a very sharp absorption band due to the stretching vibration of the methanolic O-H group. Non-isothermal kinetics of the thermal decomposition were studied using the model-free isoconversional method. Based on isoconversional dependencies, a multi-step mechanism with parallel reactions was recognised for the decomposition of the complex.