Stabilization of Cu II -I Bonds Using 2-Benzoylpyridine Thiosemicarbazones - Synthesis, Structure, Spectroscopy, Fluorescence, and Cyclic Voltammetry (original) (raw)
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Polyhedron, 2018
Equimolar reaction of copper(I) iodide with PPh3 in acetonitrile formed compound of empirical composition, {CuI(Ph3P)} and its further reaction in chloroform with pyridine-2-carbaldehyde-N-methyl thiosemicarbazone {(C5H4N)HC 2 =N 3-N 2-(H)-C 1 (=S)N 1 HR; R = Me; HL 1-Me} formed crystals of complex, [CuICl(Ph3P)(κS 1-H2L 1-Me] 1a, tetramer [Cu4I4(Ph3P)4] 1b and free HL 1-Me 1c, separated from the same reaction vessel. The formation of product 1a involved abstraction of chlorine from chloroform and has pyridine-N-protonated thio-ligand. Copper(I) bromide/chloride with Ph3P and HL 1-Me or H2L 1-Et also formed pyridyl protonated, [CuBr2(Ph3P)(κS 1-H2L 1-Me)] 2, [CuCl2(Ph3P)(κS 1-H2L 1-Me)] 3, [CuBr2(Ph3P)(κS 1-H2L 1-Et)] 4 and [CuCl2(Ph3P)(κS 1-H2L 1-Et)] 5. The products similar to 1b and 1c were also identified in these reactions. In these four coordinated complexes the pyridine protonated thio-ligands are coordinating through sulfur only.Copper(I) halides with benzaldehyde-N 1-substituted thiosemicarbazones {(C6H5)HC 2 =N 3-N 2 (H)-C 1 (=S)-N 1 HR; R = Me, Et; HL 2-Me; HL 2-Et} and Ph3P have yielded halogen bridged dinuclear complexes, [Cu2(-X)2(κS 1-HL 2-R)2(Ph3P)2] (X, R
Polyhedron, 2006
Reactions of benzophenone thiosemicarbazone (Hbztsc, Ph 2 C@N-NH-C(@S)-NH 2 ) with copper(I) chloride/bromide in the presence of two moles of PPh 3 , formed monomeric tetrahedral complexes, [CuX (g 1 -S-Hbztsc)(PPh 3 ) 2 ] AE CH 3 CN (X = Cl, 1; Br, 2). It did not form similar complex with copper(I) iodide; rather it formed a trigonal planar complex [CuI(g 1 -S-Hbztsc) 2 ] (3) with two moles of Hbztsc in absence of PPh 3 . All the complexes have been characterized with the help of elemental analyses, IR, 1 H, 13 C, and 31 P NMR spectroscopy, and single crystal X-ray crystallography. The crystal structure of ligand is also described. In all the complexes, benzophenone thiosemicarbazone is acting as a neutral S donor ligand in g 1 -S bonding mode. NMR data support that the complexes remain stable in solution phase.
Polyhedron, 1996
Abstraet--Copper(II) complexes of general empirical formulae, [Cu(NNS)X] "xH20 (NNS = uninegatively charged tridentate ligand formed by condensation of 6-methylpyridine-2-aldehyde with thiosemicarbazide ; X = CI, Br, NO3, and CH3COO; x = 0, 1) and [Cu(NNS)2] 9 0.5H20 have been prepared and characterized by conductance, magnetic, electronic and infrared spectroscopic measurements. Magnetic and spectral data support a square-planar structure for [Cu(NNS)X] (X = C1, Br, NO3, CH3COO) and a distorted octahedral structure for [Cu(NNS)2] "0.5H20. The crystal and molecular structure of [Cu(NSS)C1] has been determined by X-ray diffraction. This complex has a distorted square-planar geometry with the copper(II) ion lying in an approximate plane of four coordinating atoms, three of which come from the 6-methylpyridine-2-carboxaldehyde thiosemicarbazone and the fourth coordination site is occupied by the chloride ligand. The thiosemicarbazone is present as the thiolate form and is coordinated to the copper(II) ion via the pyridine nitrogen atom, the azomethine nitrogen atom and the mercaptide sulfur atom.
Zeitschrift für anorganische und allgemeine Chemie, 2007
Reaction of copper(I) halides with acetone thiosemicarbazone (Hactsc) and acetaldehyde thiosemicarbazone (Hmtsc) in CH 3 CN in the presence of PPh 3 has formed dimeric complexes of type, [Cu 2 (µ-X) 2 (η 1-S-Htsc) 2 (Ph 3 P) 2 ] (Htsc: X; Hmtsc, Br, 1; I, 2; Hactsc, I, 3; Cl, 5), and a monomer, [CuBr((η 1-S-Hactsc)(Ph 3 P) 2 (4). The complexes have been characterized using analytical data, spectroscopy and X-ray crystallography (1Ϫ4). The presence of methyl substituents at C 2 carbon of thiosemicarbazone seems to
Copper(II) complexes of 2-benzoylpyridine 4N-substituted thiosemicarbazones
Polyhedron, 1995
2-Benzoylpyridine 4N-substituted thiosemicarbazones commonly coordinate as neutral tridentate ligands to give five coordinate [Cu(HL)CI2] complexes when prepared in boiling isopropanol. However, when prepared in boiling ethanol, the anion (loss of the 3Nhydrogen) coordinates as a tridentate ligand to give [CuLC1] complexes. Representative
Ligand influence on the electrochemical behavior of some copper(II) thiosemicarbazone complexes
Transition Metal Chemistry, 2005
The redox properties of the title mono- and binuclear copper(II) chelates have been investigated by cyclic voltammetry in DMF at a working platinum electrode. The cathodic reduction and anodic oxidation of the investigated chelates produced the corresponding electrochemical Cu I and Cu III species stable only in the voltammetric time scale, The effects of substituents on E1/2, redox properties and stability towards oxidation of the complexes were related to the electron-withdrawing or releasing ability of the substituents on the C=N1[H, CH3 or C6H5] and/or N4H [H, C2H5, C6H5 or pClC6H4] groups, The electron attracting substituents stabilize the Cu(II) complexes while electron-donating groups favor oxidation to Cu(III). Changes in the E1/2 for the complexes due to remote substituent effects could be related to changes in basicity of N4H.Thus, variation in N41-J has more influence on E1/2 than changes in C=N1. The correlation between E1/2 of the complexes and pK a of the ligands has been attributed to the spherical potential generated by the electron density of the donor atoms at the antibonding d orbitals.
Structural Chemistry, 2007
The reaction of copper(II) chloride dihydrate with 2-hydroxy-3-methoxybenzaldehydethiosemicarbazone (HL) ligand in a 1:1 ratio forms the complex [Cu(L)(Cl)] Á H 2 O. The complex is characterized by spectroscopic, electrochemical, and thermal analysis. X-ray crystallographic analysis reveals that the central copper atom displays the distorted square planar geometry. The water molecule present in the lattice participates in a strong hydrogen bonding network, which leads to a 2D supramolecular arrangement.