Thioether-oxime complexes of Nickel(II) and Copper(II)

Nickel(II) and Copper(II) complexes of tetra-and pentadentatethioether-oxime ligands have been synthesized. An extraordinary range ofproperties are exhibited by the complexes. The tetradentate thioether-oximecomplexes of copper(II) form axial/equatorial dimeric complexes in the solidstate. These complexes exhibit weak ferromagnetic coupling betweenadjacent copper(II) ions. ESR spectra reveal that the dimer is broken insolution, and indeed the ESR spectra reveal tetragonal symmetry about thecopper(II) ions in the tetradentate thioether-oximes. The electrochemistry of these complexes supports the fact that oxime-containing ligands stabilizecopper(II). Nickel(II) forms a wide range of structures with the tetradentate ligands; the geometries vary from low-spin square planar to high-spin trinuclear complexes. The nickel(II) ions in trimeric complexes are disposed at the corners of an isosceles triangle and couple to each other through weak antiferromagnetic interactions. The electrochemistry of the trimeric nickel(II) complexes reveals that Ni(III) is attainable, due to the presence of anionic donors. Nickel(II) and Copper(II) form octahedral and square-pyramidal complexes with the pentadentate thioether-oxime ligands. The electrochemistry of the Ni(II) complexes reveals that most of the pentadentate ligands can stabilize both Ni(I) and Ni(III)Ph.D., Inorganic Chemistry -- Drexel University, 200

PH characterization of urease using Raman Spectroscopy

Jack bean urease is a complex biochemical enzyme with the unique monomeric structure of polypeptides with an active site containing 2 nickel ions. Its pH-based characterization is spectroscopically investigated in an acidic (Hydrochloric acid) environment for understanding its limit of detection

Nickel(II), Nickel(I), and Nickel(O) Complexes with 1,8-Bis(2′-pyridyl)-3,6-dithiaoctane

Nickel complexes with 1,8-bis(2′-pyridyl)-3,6-dithiaoctane (Pdto) are synthesized; Ni(Pdto)(H 2O) 2(ClO 4) 2 is studied by X-ray diffraction

The 1,8-bis(2′-pyridyl)-3,6-dithiaoctane Complex of Nickel(II): X-ray Crystal Structure and Borohydride Adduct Formation

The quadridentate dipyridyl-dithioether ligand 1,8-bis(2′-pyridyl)-3,6-dithiaoctane (Pdto) forms a pseudooctahedral complex with nickel(II). Blue [Ni(Pdto)(OH2)2](ClO4)2 crystallizes in the space group P21/c, with a= 11.677(5), b= 13,255(2), c= 15.804(4) Å, β= 107.45(3)° and Z=4. The ligand is folded about the Ni(II) ion so that the water ligands are cis within an O2S2 plane and the pyridines mutually trans. Reduction by sodium amalgam yields a nickel (I) complex with an axial EPR spectrum, whereas borohydride reduction is very slow. Indeed, the pink adduct [Ni(Pdto)(BH4)]+ has substantial stability in solution. © 1998 Elsevier Science S.A. All rights reserved

Modeling of Ni-Fe-Center of Ni-CO-Dehydrogenases by Nickel Complexes with Thiaazaligands

Three new nickel(II) complexes with ligands 1,8-bis(2′-pyridyl)-3,6-dithiaoctane (Pdto) and dithiosemicarbazone of 4,7-dithiadecane-2,9-dione (DtdtzH 2) of composition Ni(Pdto)(H 2O) 2(ClO 4) 2, Ni(DtdtzH 2)(Cl0 4) 2 and Ni(Dtdtz) were prepared, their molecular structures, spectral and redox-properties were studied. The possibilities of chemical reduction of Ni(Pdto)(H 2O) 2(ClO 4) 2 to nickel(I) and nickel(0) species and the reaction of nickel(I) complex with CO were shown, which may be described as the modeling of one of the stages of reactions with CO on active Ni-Fe-site of Ni-CO-dehydrogenases. It was found that Ni(DtdtzH 2)(ClO 4) reacted with (Et 4N) 2[Fe 4S 4(SBz) 4] (BzSH = C 6H 5CH 2SH) forming adduct. In the row of studied complexes Ni(Pdto) (H 2O) 2(ClO 4) 2 maybe described as the best structural model of Ni-Fe-site of Ni-CO-dehydrogenases on the redox properties