Ranford,John D
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Publication Platinum(II) triammine antitumour complexes: Structure-activity relationship with guanosine 5′-monophosphate (5′-GMP)(2005-02-10) Jin, V.X.; Tan, S.I.; Ranford, J.D.; CHEMISTRYThe multinuclear ( 1H, 15N, 31P and 195Pt) NMR spectroscopies, ES-MS and HPLC have been employed to investigate the structure-activity relationship for the reactions between guanosine 5′-monophosphate (5′-GMP) and the platinum(II)-triamine complexes of the general formulation cis-[Pt(NH 3) 2(Am)Cl] NO 3 (where Am represents a substituted pyridine). The order of reaction rate of the reactions was found to be: 3-phpy > 4-phpy > py > 4-mepy > 3-mepy > 2-mepy. The two basic factors, steric and electronic, were attributed to the order of the binding rate constants. A possible mechanism of the reaction of cis-[Pt(NH 3) 2(Am)Cl] + with 5′-GMP suggested that the reactions proceed via direct nucleophilic attack and no loss of ammonia. cis-[Pt(NH 3) 2(Am)Cl] + binds to the N7 nitrogen of the guanine residue of 5′-GMP to form a coordinate bond with the Pt metal centre. This mechanism is apparently different from that of cisplatin. The pK a value of cis-[Pt(NH 3) 2(4-mepy)(H 2O)](NO 3) 2 (5.63) has been determined at 298 K by the use of distortionless enhancement by polarization transfer (DEPT) 15N NMR spectroscopy and compared to the pK a value of cis-[PtCl(H 2O)(NH 3) 2] +. © 2004 Elsevier B.V. All rights reserved.Publication Thermal conversion of a helical coil into a three-dimensional chiral framework(1999-12-03) Ranford, J.D.; Vittal, J.J.; Wu, D.; Yang, X.; CHEMISTRYThermal dehydration results in the solid-state supramolecular conversion of the helical coordination polymer [{[Cu(sala)]2(H2O)}(n)] into the chiral three-dimensional covalent open network [{Cu(sala)}(n)] (shown schematically). X-ray crystallography reveals that hydrogen bonding plays a key role in this process. H2sala = N-(2-hydroxybenzyl)-L-alanine.Publication One-dimensional coordination polymers: Cu(II) and Zn(II) complexes of N-(2-pyridylmethyl)-glycine and N-(2-pyridylmethyl)-l-alanine(2006-08-30) Wang, X.; Ranford, J.D.; Vittal, J.J.; CHEMISTRYThe crystal structures of three Cu(II) and one Zn(II) complexes of N-(2-pyridylmethyl)-l-glycine (Hpgly) and N-(2-pyridylmethyl)-l-alanine (Hpala) have been described. They are [Cu(pgly)Cl] · H2O (1), [Cu(pala)Cl] · H2O (2), [Cu(pala)(CH3COO)] · 0.75H2O (3), and [Zn(pgly)(NO3)] (4). All these compounds have 1D polymeric structures in the solid state. In 1 and 2, the chloride ions bridge [Cu(pgly)] and [Cu(pala)] fragments, respectively, to generate 1D polymers while the bridging acetate ligands are responsible for the formation of ΛΔΛΔ type spiral polymers in 3. The nitrate ion in 4 is only acting as a terminal ligand while the carboxylate oxygen atom of the pala ligand bridges the Zn(II) centers to form the zigzag coordination polymeric chain. The 1D coordination polymers in 1 and 2 have very similar arrangements although crystallized in different space groups, and host 1D water chains in their crystal lattices. © 2006 Elsevier B.V. All rights reserved.Publication Study on carbon - Hydrogen activation of ketones by Gold(III) complexes and the synthesis and characterization of two ketonylgold(III) complexes(2004-09-22) Fan, D.; Meléndez, E.; Ranford, J.D.; Lee, P.F.; Vittal, J.J.; CHEMISTRYThe acetonylgold(III) compound [Au(ppy)(CH2COCH3) Cl] (1) (ppy = 2-phenylpyridine) was unexpectedly obtained during the crystallization process of Au(III) lactate complex [Au(ppy) (CH3CHOHCOO-)Cl]. This new structure prompted us to further study the role of Au(III) complexes on the carbon-hydrogen activation of ketones. Complex [Au(ppy)(CH2COCH3) NO3] (2) was synthesized by reacting [Au(ppy)(NO3) 2] with acetone while the ketonyl Au(III) complex [Au(apd) Cl2] (3) (Hapd = 2-acetylpyridine) was obtained through carbon-hydrogen bond activation of the acetyl group. The crystal structures of 1 and 2 have common features: a square-planar Au(III) centre coordinated by one five-membered chelate ring, one acetonyl ligand and one anion (chloride or nitrate). Both structures show that carbon-hydrogen activation of acetone by 2-phenylpyridine-Au(III) complexes leads to the formation of acetonyl-Au(III) complexes. The Au-CH 2 bond lengths (2.067(7) Å, 1 and 2.059(5) Å, 2) are similar to each other but longer than the Au-C (phenyl) bond lengths. The two softest ligands (carbanion) are also cis to each other in the thermodynamically most stable isomer. In complex 3, the σ-bonded acetyl group is confirmed by 13C DEPT NMR spectroscopy. © 2004 Published by Elsevier B.V.Publication Interconversion of a monomer and two coordination polymers of a copper(II) - Reduced schiff base ligand - 1,10-phenanthroline complex based on hydrogen- and coordinative-bonding(2001-11-05) Yang, C.T.; Moubaraki, B.; Murray, K.S.; Ranford, J.D.; Vittal, J.J.; CHEMISTRYTwo compounds, [Cu3(Sbal)2(phen)(H2O)2](ClO 4)2·3H2O (1) and [Cu(H2Sbal)2(phen)](ClO4)2 (2), were isolated in successive steps from the reaction mixture containing Cu(ClO4)2·6H2O, 1,10-phenanthroline, N-(2-hydroxybenzyl)-β-alanine (H2Sbal), and LiOH in the ratio of 1:1:1:1. When the ratio of the base was doubled, the neutral monomer [Cu(Sbal)(phen)]·2H2O (3) was obtained. The cation in 1 exists as a one-dimensional polymer in the solid state, while weak O - H··O hydrogen bonds in the cation of 2 generate ΔΛΔPublication Preparation, characterisation and structures of copper(II) complexes of an asymmetric anti-cancer drug analogue(1999-10-21) Moubaraki, B.; Murray, K.S.; Ranford, J.D.; Vittal, J.J.; Wang, X.; Xu, Y.; CHEMISTRYA series of copper(II) complexes of the anti-cancer drug analogue 1,5-bis(2-pyridylmethylene)thiocarbonohydrazide (H2L) was synthesized from acid solution. The single crystal structures of two asymmetric, binuclear, complexes [{Cu2(HL)(H2PO4)2} 2][NO3]2·2H2O and [{Cu2(HL)(CF3CO2)3}2] and two mononuclear, monomeric complexes [Cu(H3L)(H2O)][ClO4]3·ZH 2O and [Cu(H3L)(NO3)2]NO3 were solved. The binuclear complexes are dimeric with three-atom anion bridges. Selective removal of one copper ion gives mononuclear monomers. The primary magnetic exchange is between copper(II) centres within a planar binuclear unit with weaker interactions via anion or sulfur bridges. © The Royal Society of Chemistry 1999.Publication Dicopper(II) Complexes of the Antitumor Analogues Acylbis(salicylaldehyde hydrazones) and Crystal Structures of Monomeric [Cu2(1,3-propanedioyl bis(salicylaldehyde hydrazone))(H2O)2]·(ClO4) 2·3H2O and Polymeric {Cu2(1,6-hexanedioyl bis(salicylaldehyde hydrazone))(1998) Ranford, J.D.; Vittal, J.J.; Wang, Yu.M.; CHEMISTRYSalicylaldehyde hydrazones derived from acyldicarboxylic acids (H4Ln, where n = 0, 1, 2, 4, 6, 8, 10, 14 and is the number of methylene units) of varying chain length have been prepared, and their dicopper(II) complexes have been isolated as bis analogues of antitumor carboxylate hydrazones. The predominant structural form adopted is polymeric, with [{Cu2Ln}m] formed in neutral or basic solution, [{Cu2(H2Ln)Cl2}m] from dilute HCl, and [{Cu2-(H2Ln)}ml·(ClO 4)2m, from dilute HClO4. The crystal structures of [Cu2(H2L1)(H2O) 2]·(ClO4)2·3H2O and [{Cu2(H2L4)(C2H5OH) 2}m]·(ClO4) 2m]·m(C2H5OH) have been determined. The structure of [Cu2(H2L1)(H2O)2]· (ClO4)2·3H2O consists of discrete di-Cu(II) molecules with nonsymmetry-related Cu(II) centers. The copper atoms are square-planar with H2L1 supplying two tridentate, monoanionic ONO domains and water completing the coordination sphere. The two metal-binding domains are inclined at 80° to each other. For [{Cu2(H2L4)(C2H5-OH) 2}m]·(ClO4) 2m·m(CVH5OH) the symmetry-related copper atoms are square-pyramidal with the base composed of H2L4. acting as a tridentate ONO chelator, and an O-bonded ethanol molecule. Axial phenolato bridges complete the coordination sphere, linking molecules to give a polymer. Compounds prepared have been characterized by a range of physicochemical and spectroscopic techniques, and proton and metal ion stability constant data have been determined.Publication Synthesis, characterization and physicochemical properties of copper(II) complexes containing salicylaldehyde semicarbazone(2003-09-01) Lee, P.F.; Yang, C.-T.; Fan, D.; Vittal, J.J.; Ranford, J.D.; CHEMISTRYCopper(II) complexes containing a series of salicylaldehyde semicarbazone ligands have been prepared and characterized by a range of physicochemical techniques. The X-ray structure of [Cu(HBnz2)Cl]·H 2O (5) (where HBnz2 is salicylaldehyde-N,N-dibenzyl semicarbazone) shows the complex is monomeric and the copper atom is four coordinated in a distorted square planar geometry. The ligand chelates the copper in a tridentate fashion through the imine N, carbonyl O and phenolato O with the fourth position being occupied by coordinated Cl. The compound [Cu(Ph2)·H2O] (4) (where Ph2 is salicylaldehyde-N,N-diphenyl semicarbazone) is also formulated as a monomer whereas all other complexes are assumed to have a side-by-side dimeric arrangement of the metal chelating with the phenolate bridging the Cu(II) centres. © 2003 Elsevier Ltd. All rights reserved.Publication Isomerism in 1D coordination polymers of Cu(II) complexes of N-(2-hydroxybenzyl)-L-valine: Influence of solvent and coordination sphere on the conformation(2004-07) Yang, X.; Ranford, J.D.; Vittal, J.J.; CHEMISTRYThe reaction of the deprotonated N-(2-hydroxybenzyl)-L-valine ligand ("Sval") with Cu(II) salts afforded [Cu2(Sval) 2(H2O)3]n, 1, which has a 1D coordination polymeric structure cross-linked by strong hydrogen bonds to give 2D hydrogen-bonded coordination polymer in the solid state. Compound 1 can lose all the water molecules bonded to Cu(II) below 110°C. However, recrystallization from aqueous solution of anhydrous 1 gave a supramolecular isomer, [Cu2(Sval)2(H2O)]n· 2nH2O, 2. Interestingly, the thermal dehydration behavior of 2 is very similar to that of 1. Pseudo-supramolecular isomeric compounds of [Cu 2(Sval)2(H2O)n·0.5nC 3H7OH, 3, and [Cu4(SVal)4(H 2O)2(C4H9-OH)n· nC4H9OH, 4, were obtained when anhydrous 1 was recrystallized from 2-proponal and 1-butanol, respectively.Publication Hexafluorosilicate coordination to the antitumour copper(II) salicylaldehyde benzoylhydrazone (H2L) system: single-crystal X-ray structure of [{Cu(HL)H2O}2SiF6]·2H2O(1995-08) Ainscough, E.W.; Brodie, A.M.; Ranford, J.D.; Waters, J.M.; CHEMISTRYThe 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. SiF6 2- 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 a = 13.677(5), b = 11.876(3), c = 20.3 A ̊, β = 105.92(3)° and Z = 4. The complex is a discrete centrosymmetric dimer, the monomeric units being bridged by the coordinated SiF6 2- 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 SiF6 2- 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. © 1995.