Preparation of three- and four-co-ordinate gold(<scp>I</scp>) complexes; crystal structure of bis[o-phenylenebis(dimethylarsine)]gold(<scp>I</scp>) bis(pentafluorophenyl)aurate(<scp>I</scp>)

The addition of 1,10-phenanthroline, o-phenylenebis(dimethylarsine), or triphenylstibine to pentafluorophenyl-(tetrahydrothiophen) gold(I) leads respectively to [Au(C6F5)(phen)], [Au(pdma)2][Au(C6F5)2], and [Au(SbPh3)4][Au(C6F5)2], the pdma derivative being the first four-co-ordinate gold(I) complex whose structure has been fully determined by X-ray diffraction; space group P, a= 10.340(3), b= 10.982(3), c= 17.612(5)Å, α= 75.45(2), β= 82.35(2), γ= 87.23(2)°, Z= 2, R= 0.043 for 5 558 unique observed reflections. The Au– As bond lengths range from 2.462 to 2.478 Å. The two independent anions are exactly linear at Au.