Crystal and absolute structure of the aquadichloro(pyridoxal thiosemicarbazone) iron(III) chloride

A new Fe(III) complex of pyridoxal thiosemicarbazone (H2L) has been characterized by single-crystal X-ray analysis. The Fe atom in the title complex, [Fe(H2L)Cl2(H2O)]Cl, has a distorted octahedral configuration formed by NSO2Cl2 donor set. Six-membered chelate ring significantly deviates from planar form. The crystal structure is stabilized by weak intermolecular C-H…π interaction directed towards the center of the pyridine ring.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Synthesis and structural characterization of Cd(II) complexes with 2-acetylpyridine-aminoguanidine - a novel coordination mode

The structures of the first two complexes with bidentate coordination of aminoguanidine Schiff base, i.e., 2-acetylpyridine-aminoguanidine (L), are reported. The complex of the formula [Cd2Cl6(HL)2] (1) was obtained in the reaction of warm aqueous solutions of chloride salts of Cd(II), Zn(II) and the ligand, while the reaction of cadmium bromide and the ligand in the presence of deprotonating agent as well as ammonium thiocyanate resulted in the formation of the complex in which Schiff base has both the role of the ligand and the counterion, viz., [HL][Cd(HL)(NCS)2XY]·H2O (2), where X is Cl- or Br-, and Y Br- or SCN-. The complexes were characterized by IR spectroscopy, elemental analysis, conductometric measurements and single crystal X-ray diffraction. The unusual bidentate coordination of the Schiff base lead to significant changes in the geometry of this molecule (from almost planar in free form and as a tridentate ligand to twisted as a bidentate ligand). Besides, in complex 1 relatively rare bridging coordination of Cl- in octahedral Cd(II) is found, while the crystal structure of complex 2 exhibits substitutional disorder, and contains four different anions: [Cd(HL)(NCS)2Br(SCN)]- (ca. 61 %), [Cd(HL)(NCS)2Cl(SCN)]- (ca. 35 %), [Cd(HL)(NCS)2Br2]- (ca. 3 %) and [Cd(HL)(NCS)2ClBr]- (ca. 1 %)

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

First cobalt complexes with methyl pyruvate semi/thiosemicarbazone - synthesis, physico-chemical and structural characterization

In the reaction of acetone solutions of CoX2∙nH2O (X = Cl, Br) with methyl pyruvate semi/thiosemicarbazone (Hmps, Hmpt) the first Co(II) complexes with these ligands, i.e., [Co(Hmps)(H2O)X2] (X = Cl (1), Br (2)), [Co(Hmpt)2][CoCl4]∙2H2О (3) and [Co(Hmpt)2]Br2∙Me2CO (4) were obtained. Complexes 1 and 2 represent the first examples of metal complexes of Hmps. All the obtained compounds were characterized by elemental analysis, conductometry, magnetic measurements, and IR spectra, and for complexes 2–4, single crystal X-ray diffraction analysis was also performed. The effective magnetic moments were close to the upper limit (5 μB) for complexes 1 and 2, and close to the lower limit (4.4 μB) for complexes 3 and 4, and as such are characteristic for high-spin Co(II) complexes. Structural analysis showed that both ligands coordinate in a neutral form in a tridentate manner, via the ester oxygen, imine nitrogen and the oxygen atom of the ureido (Hmps), or the sulfur atom of the thioureido group (Hmpt). The central metal atoms are situated in a deformed octahedral coordination environment. Complex 2 has cis-Br configuration, while complexes 3 and 4 have mer-configuration

Transition metal complexes with thiosemicarbazide-based ligands. XLIV. Aqua(3-hydroxy-5-hydroxymethyl-2-methylpyridine-4-carboxaldehyde 3-methylisothiosemicarbazone-kappa O-3,N-1,N-4)nitratocopper(II)nitrate

The title complex, [Cu(NO3)(C10H14N4O2S)(H2O)](NO3), is the first metal complex with a Schiff base derived from isothiosemicarbazide and pyridoxal (pyridoxal is 3-hydroxy-5-hydroxymethyl-2-methylpyridine-4-carboxaldehyde). The Cu-II environment is a square pyramid, the equatorial plane of which is formed by the tridentate ONN-coordinated isothiosemicarbazone and one water molecule, while the nitrate ligand is in the apical position. The existence of numerous strong intermolecular hydrogen bonds, and weak C-H...O and C-H...pi interactions, leads to a three-dimensional supramolecular structure

Transition metal complexes with thiosemicarbazide-based ligand – PartLV: Synthesis and X-ray structural study of novel Ni(II) complexeswith pyridoxal semicarbazone and pyridoxal thiosemicarbazone

Reaction of aqueous solutions of Ni(NO3)2 and pyridoxal semicarbazone (PLSC) in the presence of NaN3 afforded two complexes, viz. green, paramagnetic binuclear octahedral [Ni-2,(PLSC)2(41,,-N-3)2(N-3)(2)] 2H(2)O (1) and, as admixture, red, octahedral [Ni(PLSCH)21 - 2H(2),O (2) complex. Under the same reaction conditions, pyridoxal thiosemicarbazone (PLTSC) gave only one diamagnetic square-planar, red complex (Ni(PLTSC-H)N-3]center dot H,0 (3). In the absence of NaN3, the reaction of PLTSC and Ni(NO3)2 yielded brown paramagnetic octahedral complex [Ni(PLTSC)21(NO3)2 - H2O (4). The complexes were characterized by elemental analysis, conductometric and magnetochemical measurements, IR and UV-Vis spectra, and the octahedral complexes 1, 2 and 4 also by X-ray monocrystal diffraction method

Antibacterial activity of cobalt(II) complexes with some benzimidazole derivatives

The antibacterial activities of cobalt(II) complexes with two series of benzimidazoles were evaluated in vitro against three Gram-positive bacterial strains (Bacillus cereus, Staphylococcus aureus, and Sarcina lutea) and one Gram-negative isolate (Pseudomonas aeruginosa). The minimum inhibitory concentration was determined for all the complexes. The majority of the investtigated complexes displayed in vitro inhibitory activity against very persistent bacteria. They were found to be more active against Gram-positive than Gram-negative bacteria. It may be concluded that the antibacterial activity of the compounds is related to the cell wall structure of the tested bacteria. Comparing the inhibitory activities of the tested complexes, it was found that the 1-substituted-2-aminobenzimidazole derivatives were more active than complexes of 1-substituted-2-amino-5,6-dimethylbenzimidazoles. The effect of chemical structure on the antibacterial activity is discussed