REACTION OF COORDINATED LIGANDS. I. SYNTHESIS AND CHARACTERIZATION OF SOME LANTHANIDE COMPLEXES OF 2,6-DIACETYLPYRIDINE-2-THENOYLISONICOTINOYL DIHYDRAZONE

摘要

Reaction of [Ln(Hdapth)Cl_2(H_2O_3)Cl [Ln= La. Pr, Nd, Sm, Eu, Gd, Tb and Dy; Hdapth = 2.6-diacetylpyridine mono(2-thenoylhydrazone)]withisonicotinoylhydrazine (inh) in ethanol yielded complexes of the type[Ln(H_2dapthinh)Cl(H_2O)_2]C1_2(H_2dapthinh 2.6-diacetylpyridine-2-thenoyl isonicotinoyldihydrazone). Their chemical compositions have beenestablished from analytical, molar conductance and FABmass data. The results of IR and NMR spectral dataindicated pentadentate bonding of 2,6-diacetylpyridine-2-thenoyl isonicotinoyl dihydrazone(H_2dapthinh) to the metal ions. The electronicspectral data have been used to calculate the variousspectral parameters viz. nephelauxetic ratio (#beta#).bonding(b~1/2), Sirha (#delta#%), covalency (#eta#)and oscillator strength (P). The shape and positionsof the hypersensitive transition in the Nd(III) complexindicated the coordination number eight around theNd~(3+)ion. The symmetry of the ligand field around themetal ions is indicated from the emission spectra.