title: Organogold(III) complexes containing chelating bis(amidate) ligands: synthesis, characterization and biological activity

authors: Kilpin, Kelly Joan

subjects: Gold complexes

abstract: Reactions of cycloaurated gold(III) dichloride complexes, with 1,2-C6H4(NHCOMe)2 and silver(I) oxide, or with C2H4(NHSO2Tol)2 (Tol = p-tolyl) or 1,2-C6H4(NHSO2Tol)2 and trimethylamine, give a series of new auracyclic complexes containing the Au-NR-CH2CH2-NR (R = SO2Tol) and Au-NR-C6H4-NR (R = COMe or SO2Tol) five-membered ring systems. An X-ray structure determination on (2-bp)Au{N(COMe)C6H4N(COMe)} (2-bp = cycloaurated 2-benzylpyridine) shows the presence of puckered metallacyclic rings, with both acetyl substituents positioned below the Au(III) coordination plane. The complex (2-bp)Au{N(COMe)C6H4N(COMe)} undergoes ring cleavage in the presence of halide and water, to give the complex (2-bp)Au{N(COMe)C6H4NH(COMe)}Cl, which was characterised crystallographically, and shown to contain a monodentate amidate ligand. Biological activity studies of the new auracyclic complexes are also reported, against P388 murine leukaemia cells and a range of bacteria and fungi, with a number of complexes showing high activity.

text: Organogold(III) complexes containing chelating bis(amidate) ligands: synthesis, characterization and biological activity Reactions of cycloaurated gold(III) dichloride complexes, with 1,2-C6H4(NHCOMe)2 and silver(I) oxide, or with C2H4(NHSO2Tol)2 (Tol = p-tolyl) or 1,2-C6H4(NHSO2Tol)2 and trimethylamine, give a series of new auracyclic complexes containing the Au-NR-CH2CH2-NR (R = SO2Tol) and Au-NR-C6H4-NR (R = COMe or SO2Tol) five-membered ring systems. An X-ray structure determination on (2-bp)Au{N(COMe)C6H4N(COMe)} (2-bp = cycloaurated 2-benzylpyridine) shows the presence of puckered metallacyclic rings, with both acetyl substituents positioned below the Au(III) coordination plane. The complex (2-bp)Au{N(COMe)C6H4N(COMe)} undergoes ring cleavage in the presence of halide and water, to give the complex (2-bp)Au{N(COMe)C6H4NH(COMe)}Cl, which was characterised crystallographically, and shown to contain a monodentate amidate ligand. Biological activity studies of the new auracyclic complexes are also reported, against P388 murine leukaemia cells and a range of bacteria and fungi, with a number of complexes showing high activity.

year: 2007-01-01

title: Five-coordinate gold(III) complexes of the Kläui ligands [(η⁵-C₅H₅)Co{P(O)(OR)₂}₃]− (R°=°Me, Et)

authors: Kilpin, Kelly Joan

subjects: gold complexes

abstract: The reactions of cycloaurated gold(III) dichloride complexes [LAuCl₂] (L°=°2-C₆H₄CH₂NMe₂ or 2-C₆H₄PPh₂ NPh) with monoanionic tripodal oxygen donor Kläui ligands [(η⁵-C₅H₅)Co{P(O)(OR) ₂}₃]− (R°=°Me or Et) results in the formation of cationic gold(III) salts [LAu{OP(OR) ₂}₃Co(η⁵-C₅H₅)]+. An X-ray structure determination on [(2-C₆H₄PPh₂ NPh)Au{OP(OR) ₂}₃Co(η⁵-C₅H₅)]BF₄shows that the Kläui ligand coordinates strongly to the gold through two oxygen atoms, and weakly through the third, giving the gold(III) a distorted square pyramidal geometry. This is the first structurally characterised example of this geometry for gold(III) with ligands other than those containing rigid bipyridine or phenanthroline backbones. In solution at room temperature there is rapid interchange (on the NMR timescale) between the oxygen atoms of the Kläui ligands, which is frozen out on cooling.

text: Five-coordinate gold(III) complexes of the Kläui ligands [(η⁵-C₅H₅)Co{P(O)(OR)₂}₃]− (R°=°Me, Et) The reactions of cycloaurated gold(III) dichloride complexes [LAuCl₂] (L°=°2-C₆H₄CH₂NMe₂ or 2-C₆H₄PPh₂ NPh) with monoanionic tripodal oxygen donor Kläui ligands [(η⁵-C₅H₅)Co{P(O)(OR) ₂}₃]− (R°=°Me or Et) results in the formation of cationic gold(III) salts [LAu{OP(OR) ₂}₃Co(η⁵-C₅H₅)]+. An X-ray structure determination on [(2-C₆H₄PPh₂ NPh)Au{OP(OR) ₂}₃Co(η⁵-C₅H₅)]BF₄shows that the Kläui ligand coordinates strongly to the gold through two oxygen atoms, and weakly through the third, giving the gold(III) a distorted square pyramidal geometry. This is the first structurally characterised example of this geometry for gold(III) with ligands other than those containing rigid bipyridine or phenanthroline backbones. In solution at room temperature there is rapid interchange (on the NMR timescale) between the oxygen atoms of the Kläui ligands, which is frozen out on cooling.

year: 2009

title: Maori sustainable resource development: The challenge posed by the New Zealand media

authors: Crombie, Winifred

subjects: Maori

abstract: We report here on a small-scale research project in which a number of articles and editorials dealing with governance and resource management problems were analysed. All of these articles and editorials appeared in the same national New Zealand newspaper. Half of them were concerned with a Māori organisation, the other half were not. Our conclusion is that there are fundamental differences between the two groups of articles/editorials, differences that are attributable to attempts to reinforce a normative/paternalistic agenda that stigmatises cultural difference.

text: Maori sustainable resource development: The challenge posed by the New Zealand media We report here on a small-scale research project in which a number of articles and editorials dealing with governance and resource management problems were analysed. All of these articles and editorials appeared in the same national New Zealand newspaper. Half of them were concerned with a Māori organisation, the other half were not. Our conclusion is that there are fundamental differences between the two groups of articles/editorials, differences that are attributable to attempts to reinforce a normative/paternalistic agenda that stigmatises cultural difference.

year: 2002-09