title: Gold derivatives of scorpionates: comparison with the other coinage metal poly(pyrazolyl)borate analogues.
abstract: Gold derivatives [Au(Tpx)(PR3)](Tpx = Tp, hydrotris(pyrazol-1-yl)borate or Tp*, hydrotris(3,5-dimethylpyrazol-1-yl)borate; R = Ph or tBu) and [Au(pzTp)(PR3)x](pzTp = tetrakis(pyrazol-1-yl)borate, x = 1 or 2, R = Ph or tBu) have been synthesised and characterized both in solution (1H- and 31P[1H]-NMR) and in the solid state (IR, single crystal X-ray structure analysis, 31P CPMAS). 31P [1H] NMR solution data suggest greater stability of the tetrakis(pyrazolyl)borate relative to those of tris(pyrazolyl)borate. All compounds are fluxional at room temperature. In order to compare [Au(Tp*)(PPh3)] with analogous coinage metal adducts we have synthesized and structurally characterized [Cu(Tp*)(PPh3)] x PPh3 and [Ag(Tp*)(PPh3)] x 2MeCN. In [Au(Tp*)(PPh3)] the gold atom adopts a distorted tetrahedral geometry with <Au-P> 2.181(5) and <Au-N> 2.37(2) angstroms (cf. <Cu-P,N> 2.166(6), 2.098(1) in [Cu(Tp*)PPh3], 2.156(2), 2.075(7) in [Cu(Tp*)(PPh3)] x PPh3; and <Ag-P,N> in [Ag(Tp*)PPh3] x MeCN 2.347(12), 2.35(5) angstroms). There are three independent [Au(Tp*)(PPh3)] molecules in the asymmetric unit of the structure with their PAu...B axes lying on the cell diagonal of a cubic P213 cell, two with the same chirality aligned opposed in direction to the third which is of opposite chirality. A number of Cu, Ag and Au complexes containing scorpionate ligands have also been investigated by 31P cross-polarization magic-angle-spinning (CPMAS) NMR spectroscopy.
authors.affiliation: Dipartimento di Scienze Chimiche, Universita degli Studi di Camerino, Via S. Agostino 1, Camerino, 62032, Italy.
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Gioia Lobbia
authors.forename: John V
authors.initials: JV
authors.lastname: Hanna
authors.forename: Maura
authors.initials: M
authors.lastname: Pellei
authors.forename: Claudio
authors.initials: C
authors.lastname: Pettinari
authors.forename: Carlo
authors.initials: C
authors.lastname: Santini
authors.forename: Brian W
authors.initials: BW
authors.lastname: Skelton
authors.forename: Allan H
authors.initials: AH
authors.lastname: White