A. Sreekanth

Spectral studies and structure of a 2-hydroxyacetophenone 3-hexamethyleneiminyl thiosemicarbazonate(-2) copper(II) complex containing 1,10-phenanthroline

The spectral studies and structure of a ternary complex of copper(II) with 2-hydroxyacetophenone 3-hexamethyliminylthiosemicarbazonate (L(2-)) and 1,10-phenanthroline (phen) are reported. The thiosemicarbazone binds to the metal as a dianionic ONS-donor (L(2-)) ligand, and forms a complex of the stoichiometry [CuLphen]. The copper(II) complex was characterized by IR and UV/Vis spectroscopies, as well as by solid state room-temperature magnetic susceptibility. Spin Hamiltonian and bonding parameters of the compound are calculated from the EPR spectra. Computer simulation of EPR spectrum in DMF at 77 K aided the calculation of magnetic and bonding parameters of the compound. The structure of the compound is solved by single crystal X-ray diffraction. The geometry around copper is distorted square pyramidal.

Structural studies of six and four coordinate zinc(II), nickel(II) and dioxovanadium(V) complexes with thiosemicarbazones

Three Zn(II) complexes of di-2-pyridyl ketone thiosemicarbazone, an octahedral Ni(II) complex of 2-acetylpyridine hexamethyleneiminyl-3-thiosemicarbazone, and a V(V) complex of 2-acetylpyridine morpholyl-3-thiosemicarbazone were prepared and characterized. Crystal structure of Ni(II) and V(V) complexes are reported. The ligand in the nickel complex is found to coordinate in the thione form with a pseudo octahedral geometry and the vanadium(V) complex has trigonal bipyramidal geometry.

Synthesis and structural studies of novel Co(III) ternary complexes containing N(4)-substituted thiosemicarbazones of 2-hydroxyacetophenone and heterocyclic bases

Abstract An interesting series of eight neutral ternary Co(III) complexes of 2-hydroxyacetophenone N(4)-substituted thiosemicarbazones (H2L), bidentate heterocyclic bases 2,2′-bipyridine (bipy)/1,10-phenanthroline (phen) and azide with a general formula [MLB(N3)] were prepared. The complexes were characterized by means of spectroscopic methods. The coordination geometry around Co(III) in all the complexes is distorted octahedral with one dibasic tridentate ligand L2−, one bidentate heterocyclic base and one terminally coordinated azide group. Crystal structure of the compound CoL4bipyN3 was completely solved. All the electronic transitions were assigned. All complexes were diamagnetic indicating cobalt in a d6 strong field.

Synthesis, spectral studies and structure of 2-hydroxyacetophenone nicotinic acid hydrazone

Abstract 2-Hydroxyacetophenone nicotinic acid hydrazone (H2ApNH) was synthesized as a part of our work, in search for non-linear optical crystal based on hydrazones, and studied spectroscopically. Complete NMR assignments for the hydrazone was made using COSY homonuclear and HMQC heteronuclear correlation techniques. Solid state reflectance was also studied in order to understand the electronic structure of the synthesized compound. The crystal and molecular structures of H2ApNH were determined. The compound crystallizes into an orthorhombic lattice with a non-centrosymmetric space group Pca21 with two crystallographically unique molecules of in an asymmetric unit. The geometry reveals quasi co planarity in the whole molecular skeleton with localization of the double bonds in the CN–N–CO with an E-configuration.

Bis(μ-phenyl 2-pyridyl ketone N4,N4-butane-1,4-diylthiosemicarbazonato)bis[chlorocopper(II)]

The title compound, [Cu2(C17H17N4S)2Cl2], exhibits a dimeric structure related by a centre of symmetry. The monomers are linked to each other by the longest Cu-S apical distance observed to date among Cu(II) square-pyramidal complexes of N4-substituted thiosemicarbazones. Each Cu(II) atom deviates from the coordination square plane, which contains the pyridyl and imine N atoms, the thiolate S atom and the Cl- anion, towards the S atom of the adjacent monomer. The dimers pack in a zigzag manner through the crystal.

Bis[1-(pyridin-2-yl)­ethano­ne-κN 4-phenyl­thio­semicarbazonato-κ2N4,S]­manganese(II)

One half of the molecule of the title complex, [Mn(C(14)H(13)N(4)S)(2)], is related to the other half by a twofold axis passing through the Mn atom. This high-spin Mn atom is six-coordinated, in an octahedral geometry, by the azomethine N, the pyridyl N and the thiolate S atom of two planar 1-(pyridin-2-yl)ethanone N(4)-phenylthiosemicarbazone ligands. In the crystal, the molecules are interconnected by N-H.S and C-H.N interactions, forming a three-dimensional network.

Bis[1-(pyridin-2-yl)ethanone-κN 4-phenylthiosemicarbazonato-κ2n4, S]manganese(II)

One half of the molecule of the title complex, [Mn(C(14)H(13)N(4)S)(2)], is related to the other half by a twofold axis passing through the Mn atom. This high-spin Mn atom is six-coordinated, in an octahedral geometry, by the azomethine N, the pyridyl N and the thiolate S atom of two planar 1-(pyridin-2-yl)ethanone N(4)-phenylthiosemicarbazone ligands. In the crystal, the molecules are interconnected by N-H.S and C-H.N interactions, forming a three-dimensional network.