Synthesis And Fluorescence Properties Of Pyridine-2 ,6 - Dimethyl Acids Amino Multi-carboxyl Derivatives And Their Rare Earth Complexes Of Research

Pyridine-2,6-dicarboxylic has stronger sensitize luminescence ability for rare earth ions than salicylic,phenanthroline ligands,and as sensitizer its lanthanide(Tb³⁺,Eu³⁺)complexes are chiral complexes.So we can obtain much information from measuring Circularly Polarized Luminescence Spectra and see the local structure of biologic molecules. The substituted pyridine-2,6-dicarboxylic acid poly-carboxyl poly-amid-ocyanogen derivatives of rare earth complexes are stabile,the luminescence intensities of these complexes are strong,and the lifetime is long.They can be used to tag proteins in time-resolved fluoroimmu-noassay (TR-FIA)and applied in the fields of food,iatrology and biology.On the basis of literatures,three novel ligands named 2,2',2",2"'-[(Pyridine-2,6-diyl)bis(methylenenitrilo)]tetrakis(acetic acid), 2,6-bis(5-methyl-pyrazole-1-ylmethyl-3-carboxylic acid)pyridine and 2-(3-methyl-pyrazole-1-ylmethyl-5-carboxylic acid)-6-(5-methyl-pyrazole-1-ylmethyl-3-carboxylic acid) pyridine which starting from pyridine-2, 6-dicarboxylic were designed and synthesized.Their rare earth complexes have rigid planar structure with excellent electronic negotiability.Starting from pyridine-2,6-dicarboxylic(1),a series of novel pyridine-2,6-dicarboxylic acid derivatives were synthesized.Carboxyls were esterified by methanol,then the dimethyl pyridine-2,6-dicarboxylate (2)was deoxidized by NaBH₄-LiCl and pyridine-2,6-dimethanol (3)was prepared.the reactive conditions of reduction was optimized.40%HBr was used as reactant to make the hydroxyl be replaced by bromine ion,and 2,6-Bis(bromomethyl)pyridine(4)was prepared,and the reactive conditions of bromination was optimized.At last bromine ions were replaced by bis(carboxymethyl)amino, 2,2',2",2"'-(pyridine-2,6-diylbis(methylene))bis(azanetriyl)tetraacetate(5) was synthesized,and through hydrolyzing 2,2',2",2"'-[(Pyridine-2,6-diyl) bis(methylenenitrilo)]tetrakis(acetic acid)(6)was obtained.The bromine ions of 2,6-Bis(bromomethyl)pyridine(4)were replaced by 5-methyl-1H-pyrazole-3-carboxylate, a pair of main isomers 2,6-bis(5-methyl-pyrazole -1-ylmethyl-3-carboxylic acid methyl ester)pyridine(14)and 2-(3-methyl-pyrazole-1-ylmethyl-5-carboxylic acid methyl ester)-6-(5-methyl-pyrazole-1-ylmethyl-3-carboxylic acid methyl ester)pyridine (15)were synthesized,and through hydrolyzing reapectively, 2,6-bis(5-methyl-pyrazole-1-ylmethyl-3-carboxylic acid)pyridine(16) and 2-(3-methyl-pyrazole-1-ylmethyl-5-carboxylic acid)-6-(5-methyl-pyrazole-1-ylmethyl-3-carboxylic acid)pyridine(17)which are two novel multifunctional heterocyclic fluorescent ligands,were obtained.Compound 8,9,10,14,15,16 and 17 were not reported by references.The structures of the compounds were deduced by the ¹H nuclear magnetic resonance(NMR),elemental analysis(EA),infrared (IR)and mass spectrum(MS).The fluorescence capability of solid rare earth complexes which were obtained from 2,6-bis(5-methyl-pyrazole-1-ylmethyl-3-carboxylic acid)pyridine reacted with the hydrochloride of Tb(â…¢),Eu(â…¢),Sm(â…¢) and Gd(â…¢)were mensurated.The thermal stability of this four rare earth complexes were measured by TG-DTA.The solid rare earth complexes were obtained from the two ligands 2,6-bis(5-methyl-pyrazole-1-ylmethyl-3-carboxylic acid)pyridine(16)and 2-(3-methyl-pyrazole -1-ylmethyl-5-carboxylic acid)-6-(5-methyl-pyrazole-1-ylmethyl-3-carboxylic acid)pyridine(17)which reacted with the nitrate of Tb(â…¢) and Eu(â…¢).The fluorescence capability of the four solid rare earth complexes were measured and their fluorescence intensity were compared,the result indicated that the rare earth complexes of ligand 17 has more excellent fluorescence properties,so ligand 17 is the better sensitizer.The structures of these complexes were deduced by EA and IR.