Synthesis And Properties Of Novel Acylhydrazone Schiff Base Europium And Terbium Complexes

Rare earth complexes exhibited good optical,electric,magnetic properties,which had a very broad application prospects.A lot of rare earth complexes can be used in organic glass,agricultural film,solar fluorescent concentration detector,fluorescence analysis,etc.This paper have been designed and synthesized eight novel acylhydrazone Schiff base,and they have been characterized.The complexes of Eu and Tb nitrates with these Schiff base ligands were synthesized and characterized by elemental analysis,UV spectra,IR spectra,EDTA titrimetric analysis and molar conductivity as well as thermal analysis.The optical and electrochemical properties of rare earth(Eu,Tb)complexes in solid were studied.The main research work are as follows:(1)The benzoyl hydrazine was prepared from ethyl benzoate and hydrazine hydrate,then the benzoyl hydrazones was prepared from benzoyl hydrazine and the substituted benzaldehyde;2-chloro-N-phenylacetamide was synthesized by chloroacetyl chloride and aniline;then a series of acylhydrazone compounds were synthesized by the reaction of benzoyl hydrazones and 2-chloro-N-phenylacetamide.The fluorescence properties of the ligand and rare earth(Eu,Tb)complexes were investigated.The results showed that the central Eu3+ ion of four europium complexes was located in a symmetric coordination site,the central Tb3+ ion of four terbium complexes were located in asymmetric coordination site.The substituent changed the elecron cloud on the benzene ring,thus the emission intensity of the fluorescence was influenced.Among all target ligands,2-(N-Benzoyl-N'-benzylidene-hydrazino)-N-(4-chlorophenyl)-acetamide(L4)substituted by-Cl,achieved energy transfer best,eventually the complex had the strongest intrinsic fluorescence than that of others.The change rule of fluorescence quantum yield was according to the change rule of solid fluorescence.The electrochemical test results showed that the influence of the substituent on the benzene ring.The introduction of electron-donating group(-CH3,-OCH3)to the ligand enhanced the ability of lossing electrons,so the oxidation potentials were decreased.The inductive-conjugative effect of the electron-withdrawing group(-Cl)contributed to stablizing the electron,so the oxidation potential was increased.(2)The salicyloyl hydrazones was synthesized by salicylic hydrazide and different aldehydes.A series of acylhydrazone compounds were synthesized by the reaction of salicyloyl hydrazones and 2-chloro-N-phenylacetamide.The fluorescence properties results showed that the central rare earth ions of eitht complexes were located in asymmetric coordination site.Compared with five membered ring,benzene was isoelectronic ? bond,so the nature of the benzene ring was stable and benzene ring had good planarity,thus complexes formed from the ligand P1 and rare earth ions had good structure rigidity.The change rule of fluorescence quantum yield was according to the change rule of solid fluorescence.The electrochemical test results showed that the influence of the ligand.The electronegativity of N was stronger than C,so the electron clouds density of the pyridine ring was less than benzene ring,the oxidation potentials were increased.The heteroatomic of fural and thiophene were SP2 hybridization,they formed conjugated system containing five atoms with six ?electrons,they belonged to rich electronic system,so the oxidation potentials were decreased.