Rosa Castro

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 Znue5f8N(phen), 2.061 A for Znue5f8N(pyt) and 2.586 A for Znue5f8S. The vibrational, 1H and 13C NMR spectra of the compounds are discussed.

Electrochemical synthesis of benzothiazole-2-thionato complexes of nickel(II), zinc(II) and cadmium(II) : the crystal structure of 2,2'-bipyridine bis(benzothiazole-2-thionato)zinc(II)

The electrochemical oxidation of anodic metal (nickel, zinc or cadmium) in acetonitrile solutions of benzothiazole-2-thione (Hbztz) gave the compounds [M(bztz) 2 ] [M = nickel(II), zinc(II) and cadmium(II)]. When the oxidations were repeated in the presence of neutral ligands L′ (2,2′-bipyridine or 1,10-phenanthroline) the complexes [M(bztz) 2 L′] were obtained. The crystal structure of 2,2′-bipyridine bis(benzothiazole-2-thionato)zinc(II) was determined by X-ray diffraction. This compound consists of monomeric molecules in which the central ZnS 2 N 2 unit has a slightly distorted tetrahedral environment. The electronic, IR and 1 H and 13 C NMR spectra of the complexes are discussed and related to their structure.

Synthesis of 3-trimethylsilylpyridine-2-thione (3-Me3SipytH) complexes of nickel, copper, zinc and cadmium: crystal and molecular structure of [Cd(3-Me3Sipyt)2]

Abstract A series of complexes of Ni, Cu, Zn and Cd with 3-trimethylsilylpyridine-2-thione (3-Me 3 SipytH) as ligand has been prepared. Complexes [M(3-Me 3 Sipyt) 2 ] (M=Ni(II), Zn(II) and Cd(II)) and [Cu(3-Me 3 Sipyt)] are obtained by electrochemical oxidation of the metal in an acetonitrile solution of the neutral ligand (3-Me 3 SipytH). Adducts [Ni(3-Me 3 Sipyt) 2 L] (L=2,2-bipyridine or 1,10-phenanthroline) were obtained by addition of the extra ligand to the electrolyte phase. Treatment of [Cu(3-Me 3 Sipyt)] with 1,2-bis(diphenylphosphino)ethane (dppe) in acetone gave [Cu 2 (3-Me 3 Sipyt) 2 (dppe) 3 ]. The X-ray structure of [Cd(3-Me 3 Sipyt) 2 ] has been determined: monoclinic, space group P2 1 / n , with a = 11.818(1), b = 13.649(1), c = 13.218(1) A, β = 92.00(1)° and Z = 4. The structure was determined by direct methods and refined to R = 0.030 and R w = 0.031. In the binuclear complex each cadmium(II) centre has a trigonal bipyramidal coordination sphere with an equatorial S 3 plane, involving two bridging sulfur and one terminal sulfur. The axial positions are occupied by the nitrogen atoms of two ligands. Vibrational, electronic and 1 H, 13 C and 31 P NMR spectral data are presented for all the compounds synthesized.

4,6-Dimethylpyrimidine-2-thionato (dmpymt–) complexes of nickel(II) and cadmium(II). Crystal structure of [Cd(dmpymt)2]: a compound with a calixarene-like structure

Nickel and cadmium complexes of the anionic form of 4, 6-dimethylpyrimidine-2-thione (Hdmpymt) and their adducts with neutral ligands (1,10-phenanthroline or 2,2′-bipyridine) have been prepared by an electrochemical procedure and characterized by spectroscopic (IR, UV, 1H and 13C NMR) methods, and for the [{Cd(dmpymt)2}6] complex by X-ray crystallographic techniques. This compound is hexanuclear with an array of six cadmium atoms bridged by twelve sulfur atoms. Each cadmium atom has a distorted-octahedral cis-CdS4N2 environment with each ligand acting in a N,S bidentate S-bridging mode. The hexamer has a calixarene-like structure with cavities large enough to accommodate molecules such as acetonitrile, carbon monoxide and molecular iodine.

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 reaction of copper 3-trimethylsilylpyridine-2-thiolate with bis(diphenylphosphino)ethane. Crystal structure of μ-[1,2-bis(diphenylphosphino)ethane]bis(3-trimethylsilylpyridine2-thiolato-S) [1,2-bis(diphenylphosphino)ethane]dicopper(I), [Cu2(3-Me3Sipyt)2(dppe)3]

μ-[1,2-Bis(diphenylphosphino)ethane]bis(3-trimethylsilyl;-pyridine-2-thiolate-S) [1,2-bis(diphenylphosphino)ethane] dicopper(I), [Cu2(3-Me3Sipyt)2(dppe)3], was obtained by reaction of [Cu(3-Me3Sipyt)] with 1,2-bis(diphenylphosphino) ethane (dppe) in acetone. The compound is dimeric with dppe molecules acting as both bridging and chelating ligands and the thione coordinating in the monoanionic form through the sulfur atom. The environment around the copper is distorted tetrahedral. Crystal data: P21n, a =16.640(3), b=14.437(3), c=18.321(4) A, β=101.41(3)°, V=4312(1) A3, Z=2, Dcalc=1.299 g cm−3, R=0.0627 for 2723 reflections.

Electrochemical synthesis of zinc(II) complexes of 4,6-dimethylpyrimidine-2-thione : the crystal structure of pyridine-bis(4,6-dimethylpyrimidine-2-thiolato)zinc(II)

Abstract Electrochemical oxidation of zinc in a solution of 4,6-dimethylpyrimidine-2-thione (4,6-Me2pymtH) in acetonitrile afforded the compound [Zn(4,6-Me2pymt)2]. When pyridine (py), 1,10-phenanthroline (phen) or 2,2-bipyridine (bipy) were added to the electrolytic phase [Zn(4,6-Me2pymt)2py], [Zn(4,6-Me2pymt)2phen] or [Zn(4,6-Me2pymt)2bipy] were obtained. The crystal structure of pyridine-bis(4,6-dimethylpyrimidine-2-thiolato)zinc(II) was determined; the zinc atom has distorted trigonal bipyramidal geometry. The IR and 1H and 13C NMR spectra of the complexes are discussed and related to their structures.

Synthesis and crystal structure of μ4-oxo-hexa-(μ2-(N,S)-1-methylimidazoline-2-thionato)-tetrazinc(II)

Abstract Electrochemical oxidation of zinc in a solution of 1-methylimidazoline-2-thione (MeImtH) in acetonitrile, gives [Zn 4 O(MeImt) 6 ] whose crystal structure has been determined by X-ray diffraction. This compound contains a central oxygen atom tetrahedrally bonded to four zinc atoms, bridged by six 1-methylimidazoline-2-thionato ligands along the edges of the tetrahedron. Each zinc atom exhibits tetrahedral coordination.

ELECTROCHEMICAL SYNTHESIS AND CRYSTAL STRUCTURE OF (3-TRIMETHYLSILYLPYRIDINE-2-THIOLATO) COPPER(I), CU4(3-ME3SIPYT)4

Abstract (3-Trimethylsilyl-pyridine-2-thiolato-S,N)copper(I), [Cu(3-Me3Sipyt)], was obtained by electrochemical oxidation of copper metal in an acetonitrile solution of the neutral ligand. The compound is tetrameric and the four copper atoms are arranged with distorted tetrahedral geometry, each copper atom being trigonally coordinated to one nitrogen and two sulfur atoms of three different ligands. Crystal data: 141/a, a=14.608(2), c=19.366(4) A , V=4133(2), A , Z=4, D calc =1.581 g cm −3 , R=0.0397 for 848 reflections.