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)3X] [for X = Cl, (1); X = Br, (2) and X = I, (3)] and tris(4-methoxyphenyl)phosphine [P(panis)3], [AuP(panis)3X] [for X = Br (4) and X = I (5)] have been synthesized 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) Å; Au–Cl, 2.294(2) Å; Au–Br, 2.385(2)–2.402(2) Å; Au–I, 2.546(1)–2.554(1) Å; P–Au–X; 175.3(1)–180°]. 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)3Cl]. The 2-methoxy analogues are stabilized by significant methoxy-O⋯Au interactions.

Graphical abstractIn the series of crystallographically characterized two-coordinate complexes of gold(I) of the type [AuP(anis)3X] [where anis = tris(o-methoxyphenyl)phosphine and tris(p-methoxyphenyl)phosphine, and X = Cl, Br, I], significant Au⋯O interactions are present in the ortho-substituted isomers, most significant with tris interaction in the isomorphous pair (X = Br, I) which have perfect C3 symmetry.Figure optionsDownload full-size imageDownload as PowerPoint slide