[Synthesis and spectra of transition metals complexes RE3L6(NO3)6(H2O)2].

Schiff base 4-(p-dimethylaminobenzaldehydeamino)-4H-1,2,4-triazole(L) was synthesized from 4-amino-1,2,4-triazole and p-dimethylaminobenzaldehyde using acetic acid as the catalyst. The solid complexes RE3L6(NO3)6(H2O)2 (RE = Cu, Co, Zn, Cd; x = 3-6) were synthesized with 4-(p-dimethylaminobenzaldehydeamino)-4H-1,2,4-triazole and nitrate of transition metals in ethanol and characterized by elemental analysis, infrared spectroscopy, UV spectrum, and fluorescence spectrum. Experimental results showed that the free ligand is a thermally stable material, and its ethanol solution emitted intense blue fluorescence at the peak wavelength of 416 nm. The absorption band at about 406 nm can be assigned to the intrinsic absorption of C==N. Compared with the fluorescence emission of free ligand in ethanol solution, the emission of the complex of RE3L6 (NO3)6(H2O)2 was red-shifted to 445 nm and narrow in solution. RE(II) was coordinated with N atomy of triazole in 4-(p-dimethylaminobenzaldehydeamino)-4H-1,2,4-triazole.

[Synthesis, characterization and fluorescence of Zn3 (NCS)6 (L1)6 (NO3)2 and Ni3(NCS)6(L2)6(NO3)2].

The complexes of Zn2+, Ni2+ with 4-amino-3,5-dimethyl-1,2,4-triazole and 4-amino-1,2,4-triazole were synthesized in water, respectively. By elemental analysis, coordination titration and molar conductivities studies, the compositions of the complexes were suggested as Zn3 (NCS)6 (L1)6 (NO3)2 and Ni3 (NCS)6 (L2)6 (NO3)2 respectively. The ligands and coordination compounds were studied by means of IR spectra, UV and fluorescence excitation and emission spectra. The IR spectra studies indicate that triazolate was bonded with RE (II) through nitrogen atoms in the heterocyclic ring. The fluorescence spectra showed that the fluorescence emission intensity of Ni3 (NCS)6 (L2)6 (NO3)2 was stronger than that of Zn3 (NCS)6 (L1)6 (NO3)2.

[Synthesis and fluorescence property of new La3+ complex].

The solid complex of lanthanum nitrate hydrate with 4-(p-dimethylaminobenzaldehydeamino)-4H-1,2,4-triazole (L) LaL3 (NO3)3 x (H2O)2 x (C2 H5 OH)2 was synthesized in dry N2 atmosphere and absolute alcohol. The composition of the complex was determined by chemical and elemental analyses. The crystal structure showed that La3+ was coordinated by ten oxygen atoms with three nitrate, two water and two alcohol molecules. Characterized by elemental analysis, infrared spectroscopy, and solid fluorescence, the experimental results showed that the free ligand is a thermally stable material, and emitted intensive blue fluorescence at the peak wavelength of 451 nm. Compared with the fluorescence emission of free ligand in solid-state, the emission of complex of LaL3 (NO3)3 x (H2O)2 x (C2H5 OH)2 red-shifted to 464 nm and exhibited stronger blue fluorescence.