Terminal gold-oxo complexes

TitleTerminal gold-oxo complexes
Publication TypeJournal Article
Year of Publication2007
AuthorsCao R, Anderson TM, Piccoli PMB, Schultz AJ, Koetzle TF, Geletii YV, Slonkina E, Hedman B, Hodgson KO, Hardcastle KI, Fang X, Kirk ML, Knottenbelt S, Kogerler P, Musaev DG, Morokuma K, Takahashi M, Hil
Journal TitleJournal of the American Chemical Society
Volume129
Pages11118-11133
Date PublishedSep
Type of ArticleReview
ISBN Number0002-7863
Accession NumberISI:000249372400047
Keywords3-COORDINATE NICKEL, ALKOXO, AMBIENT-TEMPERATURE, CATALYTIC-OXIDATION, COBALT(III) IMIDO, complexes, IMIDO COMPLEXES, NONHEME OXOIRON(IV), OXYGEN-ATOM TRANSFER, ray crystal-structure, THIOETHER-OXIDATION
Abstract

In contradiction to current bonding paradigms, two terminal Au-oxo molecular complexes have been synthesized by reaction of AuCl3 with metal oxide-cluster ligands that model redox-active metal oxide surfaces. Use of K-10[alpha(2)-P2W17O61]-20H(2)O and K2WO4 (forming the [A-PW9O34](9-) ligand in situ) produces K15H2[Au(O)(OH2)P2W18O68]center dot 25H(2)O (1); use of K-10[P2W20O70(OH2)(2)]center dot 22H(2)O (3) produces K7H2[Au(O)(OH2)P2W20O70(OH2)(2)]center dot 27H(2)O (2). Complex 1 crystallizes in orthorhombic Fddd, with a = 28.594(4) angstrom, b = 31.866(4) angstrom, C = 38.241(5) angstrom, V = 34844(7) angstrom(3), Z = 16 (final R = 0.0540), and complex 2 crystallizes in hexagonal P6(3)lmmc, with a = 16.1730(g) angstrom, b = 16.1730(g) angstrom, c = 19.7659(15) angstrom, V = 4477.4(5) angstrom(3), Z = 2 (final R = 0.0634). The polyanion unit in 1 is disorder-free. Very short (similar to 1.76 angstrom) Au-oxo distances are established by both X-ray and 30 K neutron diffraction studies, and the latter confirms oxo and trans aqua (H2O) ligands on Au. Seven findings clarify that Au and not W is present in the Au-oxo position in 1 and 2. Five lines of evidence are consistent with the presence of d(8) Au(III) centers that are stabilized by the flanking polytungstate ligands in both 1 and 2: redox titrations, electrochemical measurements, 17 K optical spectra, Au L-2 edge X-ray absorption spectroscopy, and Au-oxo bond distances. Variable-temperature magnetic susceptibility data for crystalline 1 and 2 establish that both solids are diamagnetic, and P-31 and O-17 NMR spectroscopy confirm that both remain diamagnetic in solution. Both complexes have been further characterized by FT-IR, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and other techniques.

DOI10.1021/ja072456n
Alternate JournalJ. Am. Chem. Soc.