David M. L. Goodgame

A New Type of Metal‐Organic Large‐Pore Zeotype

A significant step towards the development of a new family of metal-organic zeolite analogues has been achieved by binding zinc ions to the anion of 4,6-di(1-imidazolyl)-1,3,5-triazine-2-one to produce a novel uncharged large-pore zeotype capable of incorporating a range of guest molecules.

Relatively long-lived chromium(V) species are produced by the action of glutathione on carcinogenic chromium(VI)

X-Band EPR studies on aqueous solutions of potassium dichromate and gamma-L-glutamyl-L-cysteinylglycine (reduced glutathione) at pH 6-8 have shown the formation of several relatively long-lived chromium(V) species. The major species formed at high glutathione:Cr(VI) ratios is characterised by an EPR band at g = 1.995, but the dominant complex at equimolar ratios produces a signal at g = 1.985.

Possible mode of action of anti-tumour platinum drugs: X-ray evidence for cis binding by platinum of two inosine 5′-monophosphate molecules via the N(7) positions

Abstract Action of cis -[Pt(NH 3 ) 2 (H 2 O) 2 ] 2+ on the disodium salt of inosine 5′-monophosphate produces the ion [Pt(NH 3 ) 2 (5′-IMP) 2 ] 2- . X-ray structural evidence shows that platinum binds to the two nucleotide moieties via the N(7) positions on the bases. The implications of this finding are discussed in terms of possible modes of anti-tumour action of platinum compounds.

The nature of the active site in bis(imino)pyridine iron ethylene polymerisation catalysts

Mossbauer and electron paramagnetic resonance (EPR) spectroscopic studies reveal that the iron centres in bis(imino)pyridine iron(II) olefin polymerisation pre-catalysts of the type LFeCl2 are oxidised upon treatment with methylaluminoxane (MAO) to give an active species that contains iron solely in the +3 oxidation state

Formation of an infinite interpenetrating three-dimensional network by tris(N,N′-butylenebismidazole)manganese(II) tetrafluoroborate

The structure of the complex Mn(N,N′-butylenebisimidazole)3(BF4)2 comprises two equivalent, mutually interpenetrating three-dimensional network of 4-membered rings.

X-ray structure of a hydrated nickel salt of guanosine 5′-monophosphate; Evidence for the absence of direct metal-phosphate bonding

Abstract An X-ray structure determination of the complex [Ni(5′-GMP)(H2O)5]. 3H2O has shown that the metal atom coordinates to the nucleotide only at the N(7) position on the guanine moiety. There is no direct metal-phosphate bonding, although intramolecular hydrogen bonding between coordinated water molecules and the phosphate group may be an important stabilizing element in the structure.

X-ray evidence for adenine N(1)-metal bonding in a cobalt-9-methyladenine complex

Abstract X-Ray investigation of the compound CoCl2 (9-methyladenine) has shown that adenine moiety utilizes N(1) and N(7) sites in binding to the metal. This involvement of the N(1) site may well be of relevance in understanding the denaturing of DNA by metal ions.

Anion-dependence of the polymeric structures of manganese(II) complexes of N,N′-butylenebis(imidazole)

Abstract The preparations and X-band EPR spectra are reported of a series of manganese(II) complexes with N,N′-butylenebis(imidazole) (=BBI) of the types Mn(BBI)2X2 (X = Cl, Br, NO3, NCS) and [Mn(BBI)3]X2 (X = ClO4, I). An X-ray crystallographic study on Mn(BBI)2Cl2 (1) shows that each Mn atom is coordinated to four imidazole nitrogen atoms and two chloride ions in a trans-octahedral arrangement and that the BBI ligands link the Mn centres into sheets of contiguous 44-membered rings. X-Ray studies on [Mn(BBI)3](ClO4)2, and on analogous compounds containing combinations of ClO4−\PF6− or ClO4−\AsF6− as counter anions, reveal the formation of a family of interpenetrating network structures with anion-dependent cavity sizes.

Crystal structure and EPR spectrum of bispyridinium bis(citrato)chromium(III) tetrahydrate

Abstract Citric acid reacts with chromium(VI) in aqueous solution leading to the formation of chromium(V), easily detectable by EPR. However, the redox reaction goes further with the formation of a chromium(III) citrate complex. This has been crystallized as the pyridinium salt and analysed by EPR and X-ray diffraction. The structure contains discrete Cr(Cit)22− units, in which the chromium atom is octahedrally coordinated by two tridentate citrate anions. The anions and the solvate water molecules are linked by an extensive set of hydrogen bonds. The X-band and Q-band EPR spectra are well resolved, showing a large and highly anisotropic zero-field splitting.

The first structurally characterized silver/lanthanide heterometallic complex; synthesis and crystal structure of Ag[Gd(dipic)2(H2O)3]·3H2O (where H2dipic = 2,6- pyridinedicarboxylic acid)

Abstract Reaction of the silver(I) complex Ag(Hdipic)(H2dipic)·H2O, where H2dipic = 2,6-pyridinedicarboxylic acid, with gadolinium(III) nitrate in aqueous methanol gave the heterometallic complex Ag[Gd(dipic)2(H2O)3]·3H2O (1), which has been characterized by X-ray diffraction. Each gadolinium atom is nine-coordinate and has two tridentate dipic2− ions and three water molecules bonded in a tricapped trigonal prismatic geometry. The silver atoms bind to the carboxylate groups of both dipic ligands forming polymeric Gd-carboxyl-Ag-carboxyl-Gd chains.