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A chelating ligand of thioether with ONS donor Schiff base HL [(E)-2-(((2-(benzylthio)phenyl)imino)methyl)napthalen-1-ol] and its metal complexes (RuL1 and RuL2) have been synthesized. They have been characterized by UV–Vis, FTIR, 1H NMR, 13C NMR, mass spectrometry methods. The formulas of the synthesized compounds have been confirmed by elemental analysis and magnetic susceptibility measurements. The binding ability studies of the ligand (HL) and its Ru complexes (RuL1 and RuL2), with calf-thymus DNA have been explored by the absorption titration method. The binding interaction study reveals that the ligand (HL) and the complex RuL1 interact with CT-DNA through an intercalative mode of binding whereas the complex RuL2 does not show any interaction with CT-DNA due to steric effect. [ABSTRACT FROM AUTHOR]

Facile one pot synthesis of a series of seven tetraamide macrocyclic complexes of first row transition metal ions such as Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) is carried out using malonyldihydrazide and p-nitrobenzaldehyde at room temperature using template method. The characterization and structure determination of synthesized complexes was carried out using various analytical techniques such as melting point determination, IR, UV/Visible, 1H NMR, Mass spectra, magnetic susceptibility and molar conductance measurements. The results obtained indicated towards the presence of an octahedral geometry of the complexes. The synthesized complexes were screened for their antibacterial activities. [ABSTRACT FROM AUTHOR]

Two new Co(II) complexes, [CoL2]X2∙2H2O, with N,N,N-tridentate triazine type ligand (L) and X = Cl− (1) or NO3− (2) are synthesized and characterized using elemental analysis, FTIR spectra, and single-crystal X-ray diffraction. Complexes 1 and 2 are crystallized in the centrosymmetric space groups P-1 and C2/c, respectively. The Co atoms are surrounded by two neutral tridentate ligands coordinated via nitrogen atoms, thus forming a distorted octahedral coordination sphere. Hirshfeld topology analyses of the molecular packing revealed that the polar Cl⋯H, O⋯H and N⋯H contacts are the most important intermolecular interactions while the nonpolar C⋯H and C⋯C (π–π stacking) contacts are weak and insignificant, respectively. DFT calculations indicated that the high-spin state is energetically more favored than the low-spin case. The Co(II) center transfers its spin density to the ligand donor atoms via the spin delocalization mechanism. Based on the atoms in molecules (AIM) results, all Co–N interactions have a predominant covalent character. The strength of the Co–N interactions decreases in the order Co–N(hydrazone) > Co–N(triazine) > Co–N(amine). The metal anti-bonding natural orbitals involved in the Co–N interactions have high and s-orbital characters. Both complexes showed good thermal stability up to 276°C and 250°C for complexes 1 and 2, respectively. [ABSTRACT FROM AUTHOR]

Many of the recent developments in nanoscience research using polyoxometalates (POMs) are reviewed. POMs consist of several octahedral made of transition metals (Tm) and oxygen, attached to one another by sharing oxygen atoms. This review demonstrates the important and variety role of POMs in the advances of nanotechnology. Special attention is given to the synthesis of nanomaterials using POMs, nanocomposites based POMs, nanoPOMs, and nanotubes-POMs. [ABSTRACT FROM AUTHOR]

The following article is a personal, and probably self-indulgent, review of the development of the classification of tilted octahedra in perovskite structures and my role in it. This review is not intended to be a thorough account of the topic, which has in any case been covered elsewhere, but is offered as a historical account of how the description of perovskite tilt systems in use today originally came about. [ABSTRACT FROM AUTHOR]

A kinetic study of the substitution behavior of octahedral [Ru(terpy)(bipy)(OH2)]2+ and [Ru(terpy)(tmen)(OH2)]2+ {terpy = 2,2:6',2''-terpyridine, bipy = 2,2'-bipyridine and tmen = N,N,N',N'-tetramethylethylenediamine} with thiourea, 1,3'-dimethyl-2-thiourea, and acetonitrile nucleophiles (Nu) as a function of concentration in pH of 4.0 aqueous media using UV-Vis spectroscopy has been made. The reactions are first order in both the concentration of the Nu and the ruthenium complex in accordance to the two-term rate law kobs = k2[Nu] + k-2. The ligand effect of the cis-coordinated bidentates (NN) on the substitutional lability of the aqua leaving group in the [Ru(terpy)(NN)(OH2)]2+ complexes increases in the order: NN = dppro < dopro < phen ≈ bipy < tmen < diox < Me2phen. This order reflects the steric as well as the electronic properties of the bidentate ligand where the meridionally coordinated terpy enacts stereoelectronic rigidity on the bidentate ligand in addition to providing an efficient drainage of electron density at the metal centers. In the tmen complex, the retardation of the incoming groups caused by a dominant cis σ-effect from the tmen toward the metal center controls the rate of the reaction, as a result of the induced weakening of the scorpionatic effect of the steric tmen ligand due to the strong π-repulsive backbone of the meridionally coordinated terpy. [ABSTRACT FROM AUTHOR]

A series of air-stable, low-spin Ru(III) octahedral complexes [RuX(EPh3)L] (where X = Cl/Br; E = P/As; and L = dibasic tetradentate Schiff base derived by condensation of ethylenediamine with acetoacetanilide/acetoacetotoluidide/ethylacetoacetate in 1 : 2 molar ratio in ethanol) have been synthesized from RuX3(EPh3)3 (where X = Cl/Br and E = P/As) with Schiff bases in 1 : 1 molar ratio in benzene for 6 h. These complexes were characterized by elemental analysis, spectral methods (Fourier transform infrared (FT-IR), UV-Vis, 1H- and 13C-nuclear magnetic resonance (NMR) for the ligands, and electron paramagnetic resonance (EPR)), and are examined electrochemically. The complexes were efficient catalysts for oxidation of primary and secondary alcohols in their corresponding aldehydes and ketones in the presence of molecular oxygen. These complexes were also tested for their antibacterial and antifungal activities. [ABSTRACT FROM AUTHOR]

Condensation of 1H-pyrazole-3,5-dicarboxylic hydrazide with 1H-indole-2,3-dione (isatin) yield the compartmental ligand, which is capable of encapsulating two transition metal ions namely CoII, NiII, CuII, and ZnII. The ligand is a binuclear hexadentate chelate with N4O2 donating sites. The pyrazole core provides the diazine fragment, which serves as an endogenous bridge between the two metal centers. In CoII and NiII complexes, the ligand is in the imidol form and the subsequent coordination through the imidol oxygen. In other complexes, the lactonic oxygen takes part in ligation. All the complexes are non-electrolytes and soluble in DMSO, DMF, and acetonitrile. Spectral and magnetic studies along with analytical data suggest octahedral geometry for the CoII and NiII complexes, whereas the CuII and ZnII complexes are assigned square pyramidal geometry. The CuII and NiII complexes show one electron redox behavior and the rest are electrochemically inactive. [ABSTRACT FROM AUTHOR]

The template condensation reaction of o‐phenylenediamine with 2,3‐butanedione or 2,4‐pentanedione resulted in the formation of new series of 12 and 14‐membered tetraaza macrocyclic complexes: [ML 1 Cl 2 ], [ML 2 Cl 2 ] [M&dbnd;Co(II), Ni(II) and Zn(II)]; [CuL 1 ]Cl 2 and [CuL 2 ]Cl 2 . The formation of the macrocyclic framework and the overall geometry of the complexes have been characterized by elemental analyses, FT‐IR, 1 HNMR, UV‐Visible, magnetic susceptibility and conductivity measurements. The copper(II) complexes exhibit square planar geometry, whereas an octahedral geometry is suggested for all other complexes. [ABSTRACT FROM AUTHOR]

Mono- and binuclear Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) complexes of Schiff-base ligands derived from 7-formyl-8-hydroxyquinoline with diaminonaphthalenes were prepared and characterized by elemental and thermal analysis, conductance measurements and IR spectroscopy. The structures of the solid complexes under study are established by using electronic and ESR spectroscopy and magnetic susceptibility measurements. The results show that Co(II), Zn(II) and Cd(II) complexes are tetrahedral, Ni(II) complexes are octahedral and Cu(II) complexes are either tetragonally distorted octahedral or square planar. All complexes and ligands were found to be highly active against fungi. [ABSTRACT FROM AUTHOR]