Synthesis Of The 2,6-bis (3,5-disubstituents-1,2,4-diazaphosphol-1-yl) Pyridine And Study On Their Coordination With Zinc

The neutral tridentate ligands 2,6-bis（3,5-disubstituents-1,2,4-diazaphosphol-1-yl） pyridines based on 1,2,4-diazaphosphol,could be prepared by in good yields by the reaction of potassium1,2,4-diazaphosphollide with 2,6-dibromopyridine, and via thering-closure reaction of 2,6-bishydrazinopyridine with 1,3-bis（dimethyl-amino）-2-phosphaallyl chlorides. Subsequently, reaction of thethree neutral tridentate ligands with Zn（ClO4）2·6H2O was carried out toprovide the unusual complex （mol 2:1）. In short, the field of theorganometallic chemistry of neutral tridentate ligand includingpyridine and 1,2,4-diazaphosphol were explored. The specificcontents have the following:（1） Three neutral tridentate ligands, including 2,6-bis（1,2,4-diaza-phosphol-1-yl）pyridine, 2,6-bis（3,5-di-isopropyl-1,2,4-diazaphosphol-1-yl）pyridine, 2,6-bis（3,5-di-phenyl-1,2,4-diazaphosphol-1-yl）pyridinewere synthesized by the simple salt elimination and ring-closurereaction. The above three ligands were characterized by mp, NMR andX-Ray single crystal diffraction.（2） The zinc complex was prepared by the reaction of 2,6-bis-（1,2,4-diazaphosphol-1-yl）pyridine with Zn（ClO4）₂·6H₂O （mol 2:1） inacetonitrile. The coordination mode, structural characteristic, ultraviolet and fluorescence properties of the complex were studied.The zinc complexes （mol 1:2） with another two ligands were notobtained, due to the steric effect of the substituent group （R=i-Pr, Ph）and their distorted structures.