Experimental and Theoretical Investigations of Complex Formation of Substituted Phenylazo-Derivatives of Methylphloroglucinol

Using spectrophotometric titration technique, the processes of complex formation of some phenylazo-derivatives of methylphloroglucinol (MPG) containing hydroxo-, nitro- and nitroso-substituents were studied. The spectral criteria of neutral and ionized forms of the organic ligands in their different tautomeric forms were determined.It was detected that the complex formation is accompanied by formation of one or two chelate cycles which involve azo- or nitroso-fragments and neighboring OH-groups of the organic ligands. Different types of coordination lead to different changes in the electronic absorption spectra.The DFT-B3LYP modeling of a Ni(II) complex of α-hydroxyphenylazo MPG established the most probable coordination mode of the organic ligand: tridentate chelating dianion, distorted square coordination of Ni-cations including one water molecule.  The theoretical results are in a good accordance with the experimental data

Experimental and Theoretical Investigations of Complex Formation of Substituted Phenylazo-Derivatives of Methylphloroglucinol

Using spectrophotometric titration technique, the processes of complex formation of some phenylazo-derivatives of methylphloroglucinol (MPG) containing hydroxo-, nitro- and nitroso-substituents were studied. The spectral criteria of neutral and ionized forms of the organic ligands in their different tautomeric forms were determined.It was detected that the complex formation is accompanied by formation of one or two chelate cycles which involve azo- or nitroso-fragments and neighboring OH-groups of the organic ligands. Different types of coordination lead to different changes in the electronic absorption spectra.The DFT-B3LYP modeling of a Ni(II) complex of α-hydroxyphenylazo MPG established the most probable coordination mode of the organic ligand: tridentate chelating dianion, distorted square coordination of Ni-cations including one water molecule.  The theoretical results are in a good accordance with the experimental data

An unusual coordination of a 4-azopyrazol-5-one heterocyclic derivative with metals. Synthesis, X-ray studies, spectroscopic characteristics, and theoretical modeling

A series of novel transition and rare-earth metal complexes of (Z)-4-((1-(benzo[d]thiazol-2-yl)-3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-4-yl)diazenyl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (HL) were isolated and identified by FT IR, EPR, 1H NMR, and UV–VIS spectroscopy. The crystallographic data for [Cu2Cl3(L)(H2O)]2·1.5H2O·CH2Cl2 were obtained. The compound exists in the form of a tetranuclear species with two different metal coordination modes. The coordination polyhedra of two cations can be described as somewhat distorted tetragonal pyramids as well as two other Cu atoms of the tetrameric molecule adopt the trigonal bipyramidal coordination. The bridging chloride ligands link differently coordinated metal cations. The quantum chemical calculations indicate the existence of a ferromagnetic exchange interaction in pairs. That is in agreement with the EPR spectrum of the substance. The complex formation constants in water-ethanol solutions were determined. © 2017 Elsevier B.V

Synthesis and characterization of a series of novel metal complexes of N-heterocyclic azo-colorants derived from 4-azo-pyrazol-5-one

A series of novel metal complexes of Cu(II), Co(II), Ni(II), and Zn(II) with three N-heterocyclic derivatives of 4-azo-pyrazol-5-one were isolated and identified by FT IR, 1H NMR, ESR, and UV–Vis spectroscopy. The crystallographic data for a sodium salt as well as Co(II) and Cu(II) complexes were obtained. Formation constants of the complexes in ethanol aqueous solutions were calculated. Structures of yet unstudied metal complexes were proposed based on quantum-chemical modeling at the DFT/B3LYP level. © 2016 Elsevier Lt

An unusual coordination of a 4-azopyrazol-5-one heterocyclic derivative with metals. Synthesis, X-ray studies, spectroscopic characteristics, and theoretical modeling

A series of novel transition and rare-earth metal complexes of (Z)-4-((1-(benzo[d]thiazol-2-yl)-3-methyl-5-oxo-4,5-dihydro-1H-pyrazol-4-yl)diazenyl)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one (HL) were isolated and identified by FT IR, EPR, 1H NMR, and UV–VIS spectroscopy. The crystallographic data for [Cu2Cl3(L)(H2O)]2·1.5H2O·CH2Cl2 were obtained. The compound exists in the form of a tetranuclear species with two different metal coordination modes. The coordination polyhedra of two cations can be described as somewhat distorted tetragonal pyramids as well as two other Cu atoms of the tetrameric molecule adopt the trigonal bipyramidal coordination. The bridging chloride ligands link differently coordinated metal cations. The quantum chemical calculations indicate the existence of a ferromagnetic exchange interaction in pairs. That is in agreement with the EPR spectrum of the substance. The complex formation constants in water-ethanol solutions were determined. © 2017 Elsevier B.V

Synthesis and characterization of a series of novel metal complexes of N-heterocyclic azo-colorants derived from 4-azo-pyrazol-5-one

A series of novel metal complexes of Cu(II), Co(II), Ni(II), and Zn(II) with three N-heterocyclic derivatives of 4-azo-pyrazol-5-one were isolated and identified by FT IR, 1H NMR, ESR, and UV–Vis spectroscopy. The crystallographic data for a sodium salt as well as Co(II) and Cu(II) complexes were obtained. Formation constants of the complexes in ethanol aqueous solutions were calculated. Structures of yet unstudied metal complexes were proposed based on quantum-chemical modeling at the DFT/B3LYP level. © 2016 Elsevier Lt

Trinitrotoluene as a precursor in synthesis of effective azodyes and azopygments

The results of investigations of chemical transformations of trinitrotoluene and trinitrobenzene into azodyes and azopygments are presented. About 90 new ammino- and azocompounds were synthezised and investigated by a set of spectroscopic and theoretical methods and tested as acid and disperse dyes with high resistance to physical and chemical treatments

Trinitrotoluene as a precursor in synthesis of effective azodyes and azopygments

The results of investigations of chemical transformations of trinitrotoluene and trinitrobenzene into azodyes and azopygments are presented. About 90 new ammino- and azocompounds were synthezised and investigated by a set of spectroscopic and theoretical methods and tested as acid and disperse dyes with high resistance to physical and chemical treatments