Synthesis,Structure And Properties Of Coordination Complexes Based On Zwitterionic Nicotinic Acide Ligands

The zwitterionic ligands attract the researchers' attention because their especial electrical characteristics.The zwitterionic ligands which contain the structure of nicotinic acid,have electropositive aromatic ring.The electropositive part can neutralize the electronegativity of protonation of carboxyl and make other anions,such as Cl-,OH-,SCN-,N3-,increase their competitive coordination ability.Because of their very large steric hindrance,the most studied ligands often have one or two nicotinic acids,and less research three or more nicotinic acids.This paper design experiments based on 1,1',1'-(2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene)tris-(4-carboxypyridinium)tribromide(L1)and 1,2,4,5-tetrakis-(4-carboxylatopyridinium-l-methylene)benzene(L2),with transition metal ions and some deputy bridging ligands,12 new complexes have been composed,and they have been characterized by IR spectroscopy and powder diffraction.In addition,their thermal stabilities and solid fluorescent properties have also been investigated.In this thesis,there are four complexes based on L1 and eight based on L2,complexes 2 and 3,5?8,9 and 10 are heteronuclear isomorphous,supramolecular network which constitute by hydrogen bonding system have been analyzed.The thermogravimetric data show that all complexes have good thermostability in room temperature.The fluorescence-emission curves display that the luminous mechanism of complexes 2,3 and 5?8 are Intraligand Charge Transfer,others are Ligand-to-metal charge transfer.