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Journal of The Chemical Society-dalton Transactions - J CHEM SOC DALTON TRANS. 01/1994;
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ABSTRACT: The 2-mercaptopyridine triosmium cluster complexes, [{Os3H(CO)10}2(μ-SC5H3NCO2)], [Os3H(CO)10{SC5H N(OH)}] and [Os3H(CO)10(SC5H4N)] upon exposure to irradiation at 366 nm undergo photochemical decarbonylation reactions in which the nitrogen of the mercaptopyridine ligand displaces a carbonyl on the third osmium of the thiolate-bridged triangle to yield [{Os3H(CO)10}2(μ-SC5H3NCO2)], [Os3H(CO)9{SC5H3N(OH)}] and [Os3H(CO)9(SC5H4N)]. The reactions proceed cleanly and quantum yields have been determined. The clusters have been characterised by spectroscopic means and the structures of [{Os3H(CO)10}2 (μ-SC5H3NCO2)] and [{Os3H(CO)9}(μ-SC5H3NCO2){Os3H(CO)10}] established by single-crystal X-ray analyses. In both stru osmiums form two triangles, with the carboxylate bridging one edge of one triangle and the sulphur that of a second. For [{Os3H(CO)9}(μ-SC5h3NCO2){Os3H(CO)10}] the nitrogen has displanced a carbonyl from the third somium o thiolate-bridged osmium triangle.
Journal of Organometallic Chemistry.
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ABSTRACT: The copper(I) linakge isomers of pyridine-2-cardaldehyde 2′-[yridylhydrazone (papyH), [Cu(PPh3)2(Z-papyH)]ClO4 and [Cu(PPh3)2(E-papyH)]ClO4 have been prepared by the reaction of [Cu(PPh3)2(CH3CN)2]ClO4 with the Z- and E-form of papyH. The complexes have been characterised by spectroscopic methods and single crystal X-ray diffraction analysis. In the solid state [Cu(PPh3)2(Z-papyH)]ClO4 consists of discrete monomers of distorted tetrahedral geometry, with the metal atom coordinating to the imino nitrogen and one of the pyridyl nitrogen atoms (CuN, 2.070(7), 2.117(5) Å). The second pyridyl nitrogen is involved in an intramolecular hydrogen bond with the hydrogen atom of the hydrazono moiety. The related isomer [Cu(PPh3)2(E-papyH)]ClO4 crystallises with non-equivalent molecules within the asymmetric unit. The first has a distorted tetrahedral; geometry with regular copper-nitrogen distances (CuN, 2.141(4), 2.130(6) Å), whereas in the second the copper atom is five-coordinate with a distorted trigonal bipyramidal stereochemistry and exhibits long axial copper-nitrogen distances of 2.371(5) and 2.767(5) Å. The 1H and 13C{1H} NMR spectra of [Cu(PPh3)2(E-papyH)]ClO4 show that in solution there is no isomerisation about the imino carbon-nitrogen bond and that the five-coordinate nature of the complex is retained.
Inorganica Chimica Acta. 249(1):47-55.
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ABSTRACT: The preparation of the complex [CuL(sacc)- (H2O)]·0.5H2O (HL=2-formylpyridine thiosemicarbazone, Hsacc = saccharin) from the reaction of Na(sacc) with [{CuL(CH3COO)}2] is described. The complex [CuL(bpy)](sacc)·2H2O (bpy = 2,2′- bipyridyl) is obtained if the reaction is carried out in the presence of 2,2′-bipyridyl. The complexes have been characterized by a variety of physicochemical techniques and their crystal and molecular structures determined. Crystals of [CuL(sacc)(H2O)]·0.5H2O are monoclinic, space group P21/n, with a = 7.465(7), b = 9.245(7), c = 26.209(33) Å, β = 97.18(9)° and Z = 4. Crystals of [CuL(bpy)](sacc)·2H2O are triclinic, space group P, a = 9.243(1), b = 12.393(1), c = 13.323(1) Å, α = 75.511(5), β = 67.751(5), λ = 73.294(7)° and Z = 2. Both complexes contain five coordinate copper with three donor atoms (NNS) contributed by L, which forms a tricyclic ligating system. For [CuL(sacc)(H2O)]·0.5H2O the coordination sphere is completed by a monodentate N-bound saccharinate ion and a more weakly bound water molecule giving a distorted square-pyramidal geometry. For the complex [CuL(bpy)](sacc)-2H2O the remaining coordination sites are occupied by two N atoms from 2,2′-bipyridyl, resulting in a geometry intermediate between square-pyramidal and trigonal- bipyramidal. The saccharinate ion is a non- coordinated anion.
Inorganica Chimica Acta. 172(2):185-190.
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ABSTRACT: The triosmium cluster, [Os3(CO)10(CH3CN)2], undergoes reaction with carboxylic acids to form clusters containing a chelating μ,η2-carboxylate ligand and a hydride bridge across one edge of the triangle via an intermediate species postulated, from IR and NMR studies, to contain a coordinated μ,η1-carboxylate ion. The structure of the cluster, [Os3H(CO)10(C6H4(OH)CO2)] (1), has been determined by single-crystal X-ray diffraction and contains the 2-hydroxobenzoate ligand bound via the carboxylate oxygens in the μ,η2-mode. A thiocarboxylate analogue of the postulated intermediate, viz. [Os3H(CO)10(C6H5COS)] (2), has been obtained and its structure determined by single crystal X-ray diffraction. The C6H5COS− ion, which is bound in the μ,η1-mode through the sulfur atom, bridges two of the osmium atoms of the triangle.
Journal of Organometallic Chemistry 556:197-205. · 2.38 Impact Factor
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ABSTRACT: The preparations of phenylcyanamidocopper(I) complexes of the types [Cu2(dppe)3L2]·2Me2CO [dppe = 1,2-bis(diphenylphosphino)ethane, L = a phenylcyanamide ion] and [{Cu(PPh3)2L}2] are described. The crystal structures of two of the complexes, namely [Cu2(dppe)3(4-ClC6H4NCN)2]·2Me2CO (4-ClC6H4NCN = 4-chlorophenylcyanamide) and [{Cu(PPh3)2(4-MeC6H4NCN)}2](4-MeC6H4NCN = 4-methylphenylcyanamide) have been determined by X-ray diffraction techniques. Crystals of [Cu2(dppe)3(4-ClC6H4NCN)2]·2Me2CO are orthorhombic, space group Pbca, with a= 22.397(14), b= 18.970(7), c= 20.341(5)Å and Z= 4. The complex contains centrosymmetric dppe-bridged dinuclear molecules. Each copper atom has a distorted tetrahedral geometry with the cyano nitrogen from a terminally bound [4-ClC6H4NCN]– ligand [Cu–N 1.967(5)Å], two phosphorus atoms from a chelating dppe and one from the bridging dppe making up the co-ordination sphere. Crystals of [{Cu(PPh3)2(4-MeC6H4NCN)}2] are monoclinic, space group P21/n, with a= 15.003(2), b= 13.844(2), c= 18.711(2)Å, = 101.22(1)° and Z= 2. This complex is a centrosymmetric dimer with the [4-MeC6H4NCN]– ligands bridging in a µ-1,3 fashion. Each copper atom has a distorted tetrahedral geometry, being bound to two PPh3 phosphorus atoms, a terminal cyano nitrogen atom from a [4-MeC6H4NCN]– ligand [Cu–N 2.045(2)Å] and an amido nitrogen from the centrosymmetrically related [4-MeC6H4NCN]– ligand [Cu–N 2.095(2)Å]. The v(CN) stretching vibration for the co-ordinated phenylcyanamides occurs in the 2125–2175 cm–1 range. Solid-state cross-polarisation magic-angle-spinning (CP-MAS)31P NMR spectra at 121.47 MHz for the complexes [{Cu(PPh3)2L}2](L = XC6H4NCN; X = 4-Me, 4-Cl or H) consist of two well resolved quartets of doublets arising from each of the crystallographically independent phosphorus nuclei. The doublet structure is a consequence of homonuclear phosphorus–phosphorus two-bond coupling [2J(P1–P2)= 120 Hz]. Available structural data for phenylcyanamidocopper complexes are summarised and comparison made with related pseudohalide complexes. Yes Yes
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ABSTRACT: The complex [{Cu(HL)H2O}2SiF6]·2H2O (H2L = salicylaldehyde benzoylhydrazone) has been prepared from the reaction of CuF2·2H2O in concentrated HF with ethanolic solution of H2L. SiF62− was generated by the in situ reaction of fluoride on silica. The complex has been characterized by a range of physicochemical techniques and the crystal and molecular structure determined by single-crystal X-ray diffraction. The crystals of [{Cu(HL)H2O}2SiF6]·2H2O are monocliic, space group C2/c, with and Z = 4. The complex is a discrete centrosymmetric dimer, the monomeric units being bridged by the coordinated SiF62− anion with the Si lying on the inversion centre. The copper atom has a distorted square-pyramidal geometry with three donor atoms (ONO) from the tridentate monoanionic HL− ligand and the fourth in-plane donor (O), from a water molecule. The fifth position is occupied by a less strongly bound fluorine from the bridging SiF62− anion. Alternate stacking of the dimeric units which would allow overlap of π electron density as well as H bonding involving all of the hexafluorosilicato F atoms appears to be important for the stability of the complex in the solid.
Inorganica Chimica Acta.
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ABSTRACT: The triosmium cluster, [Os3(CO)10(CH3CN)2], reacts with the difunctional thiolate-carboxylate ligands, 2-mercaptobenzoic acid (H2L1), 3-mercaptopropanoic acid (H2L2) and 2,6-dicarboxypyridine (H2L3), to form the linked clusters, [{Os3H(CO)10}2(μ-L)] (L = L1, L2 and L3). The clusters have been fully characterised by spectroscopic means and the structures of two of them, [{Os3H(CO)10}2(μ-L)] (L = L1 and L2), established by single crystal X-ray analyses. In both cases the osmiums form two triangles, with the carboxylate bridging one edge of one triangle and the sulphur that of a second.
Journal of Organometallic Chemistry 509(2):259-264. · 2.38 Impact Factor
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ABSTRACT: Copper(II) complexes of the antitumour ligand salicylaldehyde benzoylhydrazone (H2sb) have been prepared. In the presence of strong acids, complexes of the neutral ligand were isolated: [{Cu(H2sb)X2}2]·nH2O (X = Br, n X = CCl3CO2, n = 0) and [Cu(H2sb)Cl2(H2O)]. In weakly acid or neutral media, monoanionic compounds separated: Cu(HsB)X2·nH2O] (X = Cl,Br, NO3, 0.3SO4, n = 0; X = ClO4, n = 1). With base only the highly insoluble dianionic complex [{Cu(sb)}2] was isolated. Also prepared was the related anionic ligand complex [Cu(Hsa)Cl(H2O)]·H2O (H2sa = salicylaldehyde acetylhydrazone). The complexes have been characterised by a range of physicochemical techniques and the crystal and molecular structures of [{Cu(H2sb)(CCl3CO2)2}2], [{Cu(Hsb)ClO4(C2H5OH)}2] and [Cu(Hsa)Cl(H2O)]·H2O, determined by single-crystal X-ray diffraction studies. Crystals [{Cu(H2sb)(CCl3CO2)2}2] are triclinic, space group , with = 10.130(2), b = 11.660(2), c = 11.876(2)r α = 67.07(2), β = 109-09(2)γ = 107.84(2)° and Z = 2. The complex is a centrosymmetric dimer, the monomeric units being bridged through the phenol oxygen. The copper coordination is tetragonal with the equatorial donor atoms coming from the tridentate ‘ONO’ donor ligand and the symmetry-related phenol oxygen. The more weakly bound axial donor oxygens are from the coordinated trichloroacetates. Crystals of [Cu(Hsb)ClO4(C2H5OH)2] are monoclinic, space group P21/c, with a = 11.2281(8), b = 7.9129(4), c = 21.043(1) ;rA β = 98.560(6)°✓ and Z = 4. This complex is also a centrosymmetric dimer, the monomeric units being bridged through the phenoxy oxygen. The copper coordination is tetragonal with the equatorial donor atoms coming from the tridentate ‘ONO’ ligand and the symmetry related phenoxy oxygen. The more weakly bound axial donor oxygens are supplied by the ethanol and perchlorato moieties. Crystals of [Cu(Hsa)Cl(H2O)]·H2O are monoclinic, space group P21/c, with . The complex is monomeric with the copper(II) adopting a square-pyramidal coordination. The four in-plane donors are provided by the tridentate ‘ONO’ donor Hsa and an oxygen from a coordinated water molecule; the axial site is occupied by the chloride ion. Most of the complexes have low magnetic moments and are assigned dimeric side-by-side structures. Powder ESR spectra have g1 and g✓ resolved often with ΔM = 2 transitions present.
Inorganica Chimica Acta.
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ABSTRACT: The reaction of 2-(diphenylphosphino)-N-[2-(diphenylphosphino)benzylidene]benzeneamine (PNCHP) with sulfur in a 1:1 molar ratio shows the phosphorus atom nearest the imine nitrogen to be preferentially oxidised. The overall product distribution, determined by synthesising each component independently, is: 50% 2-(diphenylphosphinothioyl)-N-[2-(diphenylphosphino)benzylidene]benzeneamine (SPNCHP), 7% 2-(diphenylphosphino)-N-[2-(diphenylphosphinothioyl)benzylidene]benzeneamine (PNCHPS) and 27% 2-(diphenylphosphinothioyl)-N-[2-(diphenylphosphinothioyl)benzylidene]benzeneamine SPNCHPS (27%) with 16% of the reactant, PNCHP, remaining. The structures of PNCHP and SPNCHP have been determined by single-crystal X-ray diffraction. The PNCHP molecule has an approximate centre of symmetry with the two phosphorus atoms adopting a trans orientation with respect to each other. The two phosphorus atoms in SPNCHP also adopt a trans arrangement to minimise non-bonded steric interactions. The –CHN– ‘bridge’ linking the two phenyl rings is not coplanar with its associated phenyl ring. The single crystal X-ray structure of the solvate, SPNCHP·CH2Cl2, shows that the extent of this non-planarity is influenced by the presence of a CH2Cl2 solvent of crystallisation. Reaction of PNCHP with the strong acids, HClO4 and HBF4 results in protonation of the imine nitrogen followed by nucleophilic attack on the imine carbon by the phosphorus nearest the imine nitrogen to form the phosphonium salt [HP]X (X=ClO4 and BF4), the structures of which have been determined by X-ray crystallography. A new P–C bond is formed thus producing a five-membered heterocyclic ring.
Polyhedron 19:2585-2592. · 2.06 Impact Factor
