Structural Studies of Two-coordinate Complexes of Tris(2-methoxylphenyl)Phosphine and Tris(4-methoxyphenyl)Phosphine with Gold(I) Halides

A series of five gold(I) halide complexes with the two isomeric methoxy-substituted triarylphosphines, tris(2-methoxyphenyl)phosphine [P(oanis)3], [AuP(oanis)3 X] [for X = Cl, , (1); X = Br (2) and X = I, (3)] and tris(4-methoxyphenyl)phosphine [P(panis)3], [AuP(panis)3 X] {for X = Br (4) and X = I (5)] have been determined and characterized by single crystal X-ray diffraction and solution 31P{1H} NMR spectroscopy. The structure determinations confirm the expected presence of linear two-coordination about the gold centres in all five complexes with bond distance and angle data typical of this type of compound [Au-P, 2.239(2)-2.259(3)Ang.; Au-Cl, 2.294(2)Ang.; Au-Br, 2.385(2)-2.402(2)Ang.; Au-I, 2.546(1)-2.554(1)Ang.; P-Au-X, 175.3(1)-180deg.]. All analogues except the iodo complex 5 crystallize with one complex molecule in the crystallographic asymmetric unit. The bromo and iodo complexes 2 and 3 constitute a trigonal isomorphous set while the bromo complex 4 is also isomorphous with the previously determined chloro complex [AuP(panis)3 Cl]. The 2-methoxy analogues are stabilized by significant methoxy-O...Au interactions.