Synthesis And Characterization Of Rare Earth Complexes Of Schiff Base

Six new schiff base ligands which are derived from salicylidene-ethylenediamin e(L1),salicylidene-benzedene(L2),o-vanillin-o-phen-ylene-diamine(L3),o-vanillin and a nthra-nilic acid(H2L4),o-vanillin-alanine(KHL5) and salicylidene-valine(KHL6) have be en synthesized, and sixty-one coordination complexes which are RE (rare-earth) coo rdinated with these ligands have been synthesized in this article. The synthesis cond itions of ligands and complexes, compositions and characterizations of complexes ha ve been studied. All these ligands and complexes are first report-ed.These ligands and complexes have been characterized by elemental analysis , gravity analysis, complexometric titration, Infrared spectrum analysis(IR), Ultraviolet(UV), molar conductance analysis, thermal-gravity analysis and x-ray diffraction analysis.The optimized synthesis condition was found, reaction temperature: room temperature~80癈 , reaction time: 3-4 hours according to the different solvents. The synthesis reaction took place in anhydrous solvents. The synthesis methods are new or improved one:(1) Using the two-step synthesis procedure for refining the the ligands to assure the ligands purity and decrease the characterization difficulties.(2) Using mixed solvents to improved the synthesis conditions.(3) Using ways of changing solvents to require easily the solid complexes which are difficultly to refine.(4) Using the optimizing solvent to make the reaction temperature as low as possible and protect the composition of ligands.(5) drying the complexes at room temperature to eliminate absorbtion losses.The molar ratio of ligands and ions in the rare-earth complexes synthesized is usually 1:1 or3:2.The compositions of the synthetic rare-earth complex compounds in this paper were confirmed to be .The complex compounds derived from RE(III) and salicylidene-ethylenediamine(L1) have the following formula:[RE2L31(NO3)6](NO3)(H2O)2 [RE(III)=Y,Er,Yb,Pr,Nd,Sm,Gd,Dy,Eu,Tb,Ho,Tm,Lu]The complex compounds derived from RE(III) and salicylidene-benzedene(L2) have the following formula:[REL2(NO3)2](NO3)(H2O)4 [RE(III)=La,Y,Er,Yb,Pr,Nd,Sm,Gd,Dy,Eu,Tb,Ho,Tm,Lu]The complex compounds derived from RE(III) ando-vanillin-o-phenylene-diamine(L3) have the following formula:[REL3(NO3)2](NO3) [RE(III)=La,Y,Er,Yb,Pr,Nd,Sm,Gd,Dy,Eu,Tb,Ho,Tm,Lu]The complex compounds derived from RE(III) and o-vanillin-anthyna-nilic acid(H2L4) have the following formula:[RE(H2L4)(NO3)(H2O)](NO3) [RE(III)=La,Y,Er,Yb,Pr,Nd,Sm,Gd,Dv,Eu,Tb,Ho,Tm,Lu]The synthetic complexes derived from rare-earth elements and amino acids have thefollowing formula:RE3+ Names of ligands Compositions of complexesNd phenanthroline and o-vanillin-alanine(KHL5) [Nd(NO3) (HL5) ] (NO3)2 2H2OGd Alanineando-vanillin-alanine(KHL5) [GdL5B2 H2O] H2ONd phenanthroline and salicylidene-valine(KHL6) [Nd (L6 )(phen)2 H2O] NO3H2OY salicylidene-valine(KHL6) [Y(NO3) (HL6) H2O] NO3H2OY phenylalanine and salicylidene-valine(KHL6) [Y (HL6 )(BB)2 H2O] H2OPr phenylalanine and salicylidene-valine(KHL6) [Pr(HL6)(BB)2 H2O]H2OCombinating Archar differential and Coats-Redfern integral method which fits the nineteen kinetic equations, the calculating program was designed. The kinetic equations of thermal decomposition for complexes and the corresponding kinetic parameters were gained. The kinetic parameters include E, A, order of reaction and correlation coefficient,etc.The thermal decomposition kinetic equations in step(2) of [Y (HL6 )(BB)2 H2O] H2O canbe expressed as: f(alpha) = (1-alpha)2, E=144.1kJ/mol, LnA=35.32, n=2, r=0.9310.The thermal decomposition kin...