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A novel series of organotellurium compounds based on formazane derivatives with a general formula of ArTeBr34 and Ar2TeBr25 [Ar = 2-[{4-hydroxy-3-methoxyphenyl}{4-nitrophenyldiazenyl}methylene amino]-5-nitrophenyl] were synthesized by refluxing mercurated formazane derivative ArHgCl with TeBr4 in two different mole ratios of 1:1 and 2:1, respectively, in dry dioxane solvent under an argon atmosphere. Compounds ArTeBr3 and Ar2TeBr2 were then reduced by the action of an ethanolic solution of hydrazine hydrate to obtain Ar2Te26 and Ar2Te 7, respectively. The ligand properties of bis(2-[{4-hydroxy-3-methoxy phenyl}{4-nitrophenyl diazenyl}methylene amino]-5-nitrophenyl) telluride (7) were examined toward several metal ions through its reaction with K2PtCl4, PdCl2 · 2 H2O, K2PtCl6, RhCl3 · 3 H2O, CoCl3 · 6 H2O and NiCl2, respectively. These compounds were characterized by FTIR, UV-Vis,1H and 13C{1H} NMR spectroscopy and mass spectrometry as well as by elemental analysis, thermal analysis, magnetic susceptibility and molar conductivity. The identification of the synthesized complexes 8-13 proved that the complexes of Pt(II), Pd(II) and Ni(II) have square pyramidal geometries and are diamagnetic, while the complexes of Pt(IV), Rh(III) and Co(III) have octahedral shapes with the same magnetic behavior. The telluride 7 behaves as a neutral pentadentate ligand. [ABSTRACT FROM AUTHOR]

Graphical abstract A series of Cr(III) complexes have been synthesised that incorporate (substituted) 8-quinolinato type ligands into the coordination sphere. Both homo- and heteroleptic examples are described together with X-ray structures and luminescence properties. Abstract A series of six coordinate homoleptic and heteroleptic Cr(III) complexes have been formed that incorporate 8-quinolinato ligands. Three classes of complex have been synthesised and characterised: (i) [Cr(Q) 3 ]; (ii) [Cr(Q) 2 (H 2 O) 2 ]Cl; (iii) [Cr(Q)(N^N) 2 ](PF 6) 2 (where Q is a ligand, 8-hydroxyquinoline, 8-hydroxy-2-methyl-quinoline, or 8-hydroxy-5-nitroquinoline; N^N = 1,10-phenanthroline or 2,2′-bipyridine). Single crystal X-ray structures were obtained for four complexes giving examples of [Cr(Q) 2 (H 2 O) 2 ]Cl, two [Cr(Q)(bipy) 2 ](PF 6) 2 and [Cr(Q)(phen) 2 ](PF 6) 2. Each complex shows the ligands in the expected coordination mode with a distorted octahedral geometry evident at the metal centre. The UV–Vis. absorption data allowed assignments of the quinolinato-centred electronic transitions together with a much weaker spin allowed d–d transition (4A 2 → 4T 2) around 550 nm. Each complex was found to be luminescent in aerated MeCN solution at room temperature, which was attributed to a ligand-centred fluorescence based on the coordinated quinolinato ligand. [ABSTRACT FROM AUTHOR]

A novel set of Cobalt(II), Copper(II) and Nickel(II) complexes of ligands, (E)-2-(((2,5- difluorophenyl)imino) methyl)phenol (A), (E)-2,4-dibromo-1-((2-hydroxybenzylidene) amino) anthracene-9,10-dione (D) & (Z)-1-((1-([1,1'-biphenyl]-4-yl)-2-bromoethylidene) amino)-2,4-dibromo anthracene-9,10-dione (E) were synthesized and characterized. Their structures were investigated on the basis of CHN, conductance measurements and spectral studies (1HNMR & 13CNMR, FTinfrared and Electronic spectroscopies), cyclic voltammetry. It has observed from spectral and analytical studies that metal complexes have the composition of (ML2.X2) and one mole of ligand behaves as bidentate chelating agents around the corresponding metal ion. From solubility test, we obtained that metal complexes of ligands A, D and E had no ionic properties and dissolve partially in polar and slightly in nonpolar solvents. These results confirmed the behavior of metal complexes as weak electrolyte from their low value of molar conductivity. Conductance data and solubility test of the complexes enhanced them to be (1:2 M:L ratio). All data confirmed an octahedral geometry of these complexes and their structures as {[M (A, D or E)2(CH3COO)2], when M= Co or Ni} and {[Cu (A, D or E)2 Cl2]}. Cyclic voltammetry measurements were accomplished of Cobalt(II), Copper(II) and Nickel(II) complexes using Pt wire as counter electrode and Ag/AgNO3 as reference electrode and (Bu4N+PF6+) as supporting electrolyte. The result exhibit the irreversible process showing single one electron transfer process of Cobalt(II) and Nickel(II) complexes and unique quasi-reversible redox couple is attributed to Cu(II) complexes. [ABSTRACT FROM AUTHOR]

Two pyridyl containing thiosemicarbazone ligands have been explored in coordination chemistry with Ni(II), Cu(II) and Zn(II) salts. The resultant complexes have been characterised using a range of techniques and the structural properties elucidated. [Display omitted] The synthesis of two thiosemicarbazone derivatised ligands (L1 and L2) was accomplished via the reaction of 1-(2-pyridinyl)ethanone hydrazone and either benzoyl or pivaloyl isothiocyanate. A range of Ni(II), Cu(II) and Zn(II) mononuclear complexes of these thiosemicarbazone ligands have been synthesized providing insight on the reactivity of the ligands. These complexes (1 – 12) have been characterized by high resolution mass spectrometry, IR, UV–vis., 1H and 13C NMR spectroscopies, elemental analysis and magnetic measurements. The solid-state molecular structures of eight examples were successfully determined by single crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]