Studies On Synthesis, Characterization And Fluorescent Properties Of Salicylamide Ligands And Rare Earths Metal Complexes

Rare earth ions are the essential components in the preparation of new and ideal materials as probes in studies of biological systems because of their specific spectroscopic and magnetic properties. Among these studies, much attention has been paid to the fluorescent rare earth complexes that are found use as labels and sensors for natural and medical science, mainly due to their large Stokes shifts, narrow emission profiles, etc.. More and more chemists are attracted to design the organized molecular architectures containing trivalent rare earth ions (Eu³⁺,Tb³⁺) working as efficient light conversion devices.We have designed and synthesized acylamino compounds with carboxyl and amino. These compounds were characterized by HNMR and X-ray crystallography etc.. The fluorescence properties of rare earth complexes have been also studied. The main contents are described as following:1. The following multipodal ligands were synthesized and characterized.2-[(Diisopropylcarbamoyl)-methoxy]-N-pyridin-3-ylmethyl-benzamide2-[(Dibenzylcarbamoyl)-methoxy]-N-pyridin-3-ylmethyl-benzamide2-Diethylcarbamoylmethoxy-N-pyridin-3-ylmethyl-benzamide2-[(Methyl-phenyl-carbamoyl)-methoxy]-N-pyridin-3-ylmethyl-benzamide2-[(Diisopropylcarbamoyl)-methoxy]-N-pyridin-2-ylmethyl-benzamideN-Benzyl-2-[(diisopropylcarbamoyl)-methoxy]-benzamide2-Diethylcarbamoylmethoxy-N-pyridin-2-ylmethyl-benzamide2,2'-(2,2'-(2,2'-azanediylbis(ethane-2,1-diyl)bis(azanediyl))bis(2-oxoethane-2,1-diyl))bis(oxy )bis(N-benzylbenzamide)2,2'-(2,13-dioxo-3,6,9,12-tetraazatetradecane-1,14-diyl)bis(oxy)bis(N-benzylbenzamide)2,2',2"-(2,2',2"-(2,2',2"-nitrilotris(ethane-2,1-diyl)tris(azanediyl))tris(2-oxoethane-2,1-diyl))tr is(oxy)tris(N-benzylbenzamide) 2. The following rare earth complexes were prepared and characterized by elemental analysis, molar conductivity measurement, IR spectra,1H NMR spectra and thermal analysis.[REL1(NO3)3·H2O](RE=Eu³⁺,Tb³⁺)[REL2(NO3)3·H2O](RE=Eu³⁺,Tb³⁺)[REL3(NO3)3·H2O](RE=Eu³⁺,Tb³⁺)[REL4(NO3)3·H2O](RE=Eu³⁺,Tb³⁺)[REL5(NO3)3·H2O](RE=Eu³⁺,Tb³⁺,Gd³⁺,Nd³⁺,Y³⁺)[REL6(NO3)3·H2O](RE=Eu³⁺,Tb³⁺)[REL7(NO3)3·H2O](RE=Eu³⁺,Tb³⁺)[RE2L8(NO3)4(H2O)4-n)](NO3)2·nH2O(RE=Eu³⁺,Tb³⁺)[RE2L9(NO3)6(H2O)4-n]·nH2O(RE=Eu³⁺,Tb³⁺)[REL10(NO3)2 (H2O)2]·NO3(RE=Eu³⁺,Tb³⁺)3. The following Crystal structures of the complexes were determined by X-ray diffraction analysis.[Eu(NO3)3L5·H2O]·MeCN[Gd(NO3)3L5·H2O]·MeCN[Nd(NO3)3L5·H2O]·MeCN[Y(NO3)3L5·H2O]·MeCN[Tb(NO3)3L5·H2O]·MeCN[Tb(NO3)3L'·H2O]·MeCN4. The fluorescence properties of the lanthanide complexes were studied. The ligand with N-benzylsalicylamide terminal group had good antenna effect to the metal ions. It was suggested the lowest triplet-state energy of the ligands matches to Tb (â…¢) and Eu (â…¢).