1-Naphthylazo derivatives of some 1,3-dicarbonyl compounds and their Cu(II), Ni(II) and Zn(II) complexes

The coupling of diazotized 1-aminonaphthalene with 1,3-dicarbonyl compounds (acetylacetone, methylacetoacetate and acetoacetanilide) yielded a new series of bidentate ligand systems (HL). Analytical, IR, 1H-NMR and mass spectral data indicate that the compounds exist in the intramolecularly hydrogen bonded keto-hydrazone form. With Ni(II), Cu(II) and Zn(II), these potential monobasic bidentate ligands formed [ML2] type complexes. The IR, 1H-NMR and mass spectral data of the complexes are consistent with the replacement of the chelated hydrazone proton of the ligand by a metal ion, thus leading to a stable six-membered chelate ring involving the hydrazone nitrogen and the hydrogen bonded carbonyl oxygen. The Ni(II) and Zn(II) chelates are diamagnetic, while the Cu(II) complexes are paramagnetic. In the metal complexes of the naphthylazo derivatives of acetylacetone and methylacetoacetate, the acetyl carbonyl is involved in coordination, whereas in the chelates of the naphthylazo derivative of acetoacetanilide, the anilide carbonyl is bonded with the metal ion

Structural and DFT Studies on Molecular Structure of Ni(II) Chloride Complex with Pyridoxal Semicarbazone (PLSC). Unusual Coordination Mode of PLSC

Dedicated to the memory of Professor Ljubo Golià bstract Crystal structure of the NiCl 2 complex with pyridoxal semicarbazone (PLSC), of the empirical formula Ni(PLSC)Cl 2 · 3.5H 2 O, gives evidence for an unusual coordination mode of PLSC, observed for the first time. Namely, X-ray analysis of this complex reveales that the elementary cell consists of two monomeric complex cations 4+ , eight Cl -anions, and four molecules of crystal water. In the monomeric cation, PLSC is coordinated in the usual tridentate (ONO) way via the phenolic and carbonyl oxygen atoms and azomethine nitrogen. In contrast, in the dimeric cations, both PLSC molecules, apart from the mentioned ligand atoms, are additionally coordinated via the oxygen of the hydroxymethyl group, but in the role of a bridge, which represents the first example of this coordination mode of PLSC. In both complex cations, Ni(II) is situated in a slightly distorted octahedral environment. The ligand and the complex were additionally characterized by IR spectra and the ligand also by NMR spectra. DFT computation of molecular structure of the complex was carried out at the B3LYP/LANL2DZ level of theory

Transition metal complexes with thiosemicarbazide-based ligands. Part 60. Reactions of copper(II) bromide with pyridoxal S-methylisothiosemicarbazone (PLITSC). Crystal structure of [Cu(PLITSC−H)H2O]Br•H2O

The synthesis and structural characterization of a square-planar copper(II) complex with pyridoxal S-methylisothiosemicarbazone (PLITSC) of the formula [Cu(PLITSC−H)H2O]Br•H2O (1) as the first Cu(II) complex with monoanionic form of this ligand were described. Complex 1 together with two previously synthesized complexes [Cu(PLITSC)Br2] (2) and [Cu(PLITSC)Br(MeOH)]Br (3) were characterized by elemental analysis, IR and electronic spectra and also by the methods of thermal analysis, conductometry and magnetochemistry. [Projekat Pokrajisnkog sekretarijata za nauku i tehnoloski razvoj Vojvodine i Ministarstva nauke Republike Srbije, br. 172014

J.Serb.Chem.Soc. 68(12)919–927(2003)

Transition metal complexes with thiosemicarbazide-based ligands. Part 46. Synthesis and physico-chemical characterization of mixed ligand cobalt(III)-complexes with salicylaldehyde semi-, thiosemi- and isothiosemicarbazone and pyridin

Synthesis and characterization of Ce and La modified bismuth titanate

Bismuth titanate based nanopowders with the different content of La or Ce were synthesized by the modified sol-gel method. After calcination at 600°C, in addition to Aurivillius layered structure, a small quantity of cubic pyrochlore phase was detected in the La modified powders, while this second phase was much more pronounced in the Ce substituted powders. In fact, as the powder with the highest amount of Ce (Bi3CeTi3O12) has the pure pyrochlore phase it seems that the presence of Ce stabilizes the formation of this phase. This different infl uence of cerium and lanthanum could be explained by the incorporation of their ions on the different sites in the titanate structure. Bismuth titanate based ceramics, sintered at 1050°C/2h, had densities above 93% of theoretical density and characteristic plate-like grain morphology. Small quantity of cubic pyrochlore phase was detected only in the Ce modifi ed bismuth titanate ceramics. On the other hand, lanthanum addition caused formation of smaller grain size with pronounced plate-like morphology

Transition metal complexes with pyrazole based ligands, part 27: Structural and thermal characterization of cobalt(II) halide and pseudohalide complexes with 4-acetyl-3-amino-5-methylpyrazole

The crystal and molecular structures of four tetrahedral structurally similar [Co(aamp)(2)X-2] complexes (aamp = 4-acetyl-3-amino-5-methylpyrazole, X = Cl, Br, I and NCS) were determined by X-ray diffraction analysis and are discussed in detail. It was found that the different capacity of the ligand X (NCS vs. Cl, Br, I) for the formation of non-bonding contacts influence the mode of molecular association in the solid state. The complexes were characterized by UV-Vis spectroscopy. The first step of the thermal decomposition of the compounds was checked and is discussed in the view of the IR spectrum of the intermediate isolated from [Co(aamp)(2)Br-2] by the quasi-isothermal technique