María L. Durán

Copper(I) complexes with 4,6-dimethylpyrimidine-2-thione (Hdmpymt); the crystal and molecular structure of [Cu6(dmpymt)6]

The complex [Cu6(dmpymt)6]·H2O was synthesised by electrochemical oxidation of copper in an acetonitrile solution of the neutral ligand 4,6-dimethylpyrimidine-2-thione (Hdmpymt). The reaction of [Cu6(dmpymt)6] with 1,2-bis(diphenylphosphino)methane (dppm) and 1,2-bis(diphenylphosphino)ethane (dppe) yielded compounds of general formulae [Cu(dmpymt)(dppm)] and [Cu2(dmpymt)2(dppe)3]. The molecular structure of [Cu6(dmpymt)6] was determined: the crystals are triclinic, space group P1, a= 11.432(3), b= 13.395(2), c= 15.694(4)A, α= 80.28(2), β= 87.75(2), γ= 73.87(2)° and Z= 2. The six copper atoms are arranged with distorted-octahedral geometry, each copper atom being trigonally co-ordinated to one nitrogen and two sulfur atoms of three different ligands. Infrared, 1H, 13C and 31P NMR spectral data are presented for all the compounds.

Electrochemical synthesis of pyridine-2-thionato complexes of zinc(II) and cadmium(II) : the crystal structure of 1,10-phenanthroline-bis(pyridine-2-thionato)zinc(II)

Abstract Zinc and cadmium pyridine-2-thionato complexes, M(pyt)2, were prepared by direct electrochemical oxidation of the metal into a solution of pyridine-2-thione (pytH) in acetonitrile. Adducts of type [M(pyt)2L] (L = 2,2′-bipyridine or 1,10-phenanthroline) were obtained by addition of the ligand to the electrolyte phase. X-ray structure determination of [Zn(pyt)2phen] shows the molecule to have a distorted octahedral trans-ZnS2N4 core, with average bond distances of 2.182 A for ZnN(phen), 2.061 A for ZnN(pyt) and 2.586 A for ZnS. The vibrational, 1H and 13C NMR spectra of the compounds are discussed.

Synthesis of cobalt(II), nickel(II) and copper(II) complexes with 2-(2-hydroxyphenyliminomethyl)-1-(4-methyl-phenylsulfonamido)benzene and crystal structures of {bis(methanol)[2-(2′-N-tosylaminophenyl)iminomethyl]phenolato}nickel(II) and {bis(2,2′-bipyridine)[2-(2′-N-tosylaminophenyl)iminomethyl]phenolato}copper(II)

Abstract Electrochemical oxidation of metal anodes (cobalt, copper and nickel) in acetonitrile solutions of 2-(2-hydroxyphenyliminomethyl)-1-(4-methyl-phenylsulfonamido)benzene (H2L) gave [CoL], [CuL] and [NiL] complexes. When 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) was added to the electrolytic cell, the mixed complexes [MLL′] (M=Co, Cu, L′=bipy or M=Ni, L′=phen) were obtained. A binuclear compound of composition [Ni2L2(MeOH)4] (1) was synthesized by reaction of the ligand H2L and nickel(II) acetate in methanol. X-ray structure determination showed the compound to be binuclear, with each nickel atom coordinated to two nitrogen and two bridging phenol oxygen atoms of two dianionic ligands and two methanol molecules, in an octahedral environment. The crystal structure of [CuLbipy] (2) was determined by X-ray diffraction; with the copper atom in a distorted bipyramidal environment defined by the two bipyridine nitrogen atoms and by the phenolic oxygen and the nitrogen atoms of the dianionic ligand. The electronic and vibrational spectral data of the complexes are discussed and related to the structure.

The electrochemical synthesis of neutral copper(II) complexes of schiff base ligands: The crystal structures of bis-{n-[2-(3-methylpyridyl)]-5-methoxysalicylideneiminato}copper(II) and bis-{n-[2-(6-metrylpyridyl)]-salicylideneiminato}copper(II)

Neutral copper(II) complexes of Schiff bases derived from substituted salicylaldehydes and 2-aminopyridine methyl derivatives have been synthesized by an electrochemical procedure. The crystal and molecular structure of bis{N-[2-(3-methylpyridyl)]-5-methoxysalicylideneiminato}copper(II) and of bis{N-[2-(6-methylpyridyl)]-salicylideneiminato}copper(II) have been determined by X-ray diffraction. The former compound crystallizes in the monoclinic space group C2/c with four molecules in the unit cell and cell constants a = 16.784(2), b = 16.344(2) and c = 11.211(2) A, and β = 124.08(1)°, while the other complex crystallizes in the monoclinic space group P21/c with two molecules in a cell of dimensions a = 12.456(1), b = 7.812(2) and c = 12.047(2) A, and β = 110.48(1)°. In both structures, the metals adopt square-planar coordination geometries and the pyridyl nitrogen atoms are not coordinated. The electronic and IR spectra of the complexes are discussed and related to the structure.

The synthesis of tin(IV) complexes of 2-(2-mercaptophenyl)-imino-phenols by the electrochemical cleavage of a disulphide bond: The crystal structure of bis{2-(2-mercaptophenyl)imino-4,6-dimethoxy-phenoxy}tin(IV)

Abstract The electrochemical oxidation of anodic tin in acetonitrile solutions in the Schiff bases derived from the required salicylaldehyde and bis-(2-aminophenyl)disulphide (L 2 H 2 ) yields compounds of formulation SnL 2 . The crystal structure of bis{2-(2-mercaptophenyl) imino-4,6-dimethoxy-phenoxy}tin(IV) [SnL 1 2 ] have been determined. The tin atom has an octahedral coordination geometry with a meridional ligand occupancy; the average SnN, SnO and SnS bond lengths are 2.17, 2.07 and 2.47 A, respectively.

Electrochemical synthesis of cobalt(II) and cobalt(III) complexes of Schiff bases: The crystal structure of tris{2-[(2-methylphenyl)iminomethyl] pyrrolato}cobalt(III)

Abstract The electrochemical oxidation of anodic cobalt in an acetonitrile solution of Schiff bases (HL) derived from H-pyrrole-2-carbaldehyde and substituted anilines gives solutions from which [CoL3] complexes were obtained. When 1,10-phenanthroline (phen) or 2,2′-bipyridine (bipy) was added to the electrolytic phase, [CoL2 phen] or [CoL2 bipy] are obtained. The crystal structure of tris{2-[(2-methylphenyl)iminomethyl]pyrrolato} cobalt(III) has been determined by X-ray diffraction. The crystal structure consists of monomeric molecules in which the central CoN6 unit has a slightly distorted octahedral geometry. The electronic, IR and 1H NMR spectra of the complexes are discussed and related to the structure.

Direct electrochemical synthesis of pyridine-2-thionato complexes of nickel(II): the crystal structure of (2,2′-bipyridine)bis(pyridine-2-thionato)nickel(II)-2,2′-bipyridine(2/1)

The compound [Ni(pyt)2] has been prepared in good yield by electrochemical oxidation of the metal in a solution of pyridine-2-thione (Hpyt) in acetonitrile. When pyridine (py), 2,2′-bipyridine (bipy), or 1,10-phenanthroline (phen) is present in the electrochemical cell the corresponding adducts [Ni(pyt)2(py)2], [Ni(pyt)2(bipy)], or [Ni(pyt)2(phen)] is obtained. The crystal structure of [Ni(pyt)2(bipy)]·0.5 bipy is monoclinic, with a= 10.409(2), b= 12.013(3), c= 19.790(3)A, β= 103.95(3)°, space group P21/c, and R= 0.032 for 3 176 reflections with |Io| > 3σ|Io|. The molecule has a distorted octahedral NiN4S2 kernel, with average bond distances of 2.065 A for Ni–N and 2.485 A for Ni–S. The vibrational and electronic spectra of the compounds are discussed.

The electrochemical synthesis of zinc(II) complexes of 2-(2-mercaptophenyl)-imino-phenols and the crystal structure of bis{N,N'[dithiobis(ethylene](4,6-dimethoxysalicylideneiminato)}zinc(II)

Abstract The electrochemical oxidation of anodic zinc in acetonitrile solutions of the Schiff bases derived from the required salicylaldehyde and bis-(2-aminophenyl)disulphide (L2H2) yields compounds of formula ZnL2. The crystal structure of bis{N,N′[dithiobis(ethylene)](4,6-dimethoxysalicylideneiminato)}zinc(II) [Zn(L1 2)] has been determined. The zinc atom has a distorted tetrahedral coordination geometry derived from the iminonitrogen and phenoxy-oxygen donor atoms.

Electrochemical synthesis of metal (II) complexes of Schiff base 2-tosylamino (2′-pyridyl)aniline: the crystal structure of bis-[2-tosylamino(2′-pyridyl)anilinato]cobalt(II)

Abstract Complexes of cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) with the anion of the Schiff base 2-tosylamino(2′-pyridyl)aniline (HL) have been prepared by using an electrochemical procedure. These compounds were characterized by elemental analysis, IR, UV and NMR spectroscopy, and in the case of [CoL2] by X-ray diffraction methods. In this compound the cobalt(II) atom is in a distorted tetrahedral environment, each Schiff base anion acting as a bidentate ligand with the pyridine nitrogen atom uncoordinated.

Direct electrochemical synthesis and crystal structure of tris(pyridine-2-selenolato)indium(III)

Abstract The compound [In(pySe)3] has been prepared byt he electrochemical oxidation of the metal in an acetonitrile solution of 2,2′-dipyridyl-diselenide [(pySe)2]. The crystal structures of 2,2′-dipyridyldiselenide and [In(pySe)3] have been determined by X-ray diffraction. Crystals of [(pySc)2] are orthorhombic, space group Pna21, with cell dimensions a = 17.499(2), b = 10.842(1) and c = 5.755(1) A . The indium compound has a molecular structure and its crystallizes in the monoclinic space group P21 with a = 8.754(3), b = 12.010(2), c = 9.403(3) A and β = 113.28(1)°. The indium atom has a distorted octahedral geometry with the ligand coordinated through both nitrogen and selenium atoms.