Unusual Reactions of Potassium Dihalodicyanoaurates with Organyltriphenylphosphonium Halides

Abstract

The precipitates obtained by the interaction of potassium dichloro- and dibromodicyanoaurates with tetraphenylphosphonium, cyanomethyl- and methoxymethyltriphenylphosphonium chlorides, after standing in aqueous solution for several days followed by recrystallization from acetonitrile, formed the corresponding tetraorganylphosphonium dicyanourates [Ph4P][Au(CN)2] (1), [Ph3PCH2CN][Au(CN)2] (2), and [Ph3PCH2OMe][Au(CN)2] (3) as minor products. By the interaction of potassium dichloro-, dibromo-, and diiododicyanoaurate with hydroxymethyltriphenylphosphonium chloride in hot ethanol, the corresponding triphenylphosphinegold(I) halides (Ph3P)AuHal (Hal = Cl (4), Br (5), I (6)) were also synthesized. It has been established that carrying out these reactions in water followed by recrystallization from ethanol or acetonitrile leads to the crystalline product of an ion-exchange interaction only in the case of potassium diiododicyanoaurate ([Ph3PCH2OH][Au(CN)2I2] (7) has been obtained). Compounds 1–7 have been identified by elemental analysis, IR spectroscopy, and X-ray diffraction analysis. According to the X-ray diffraction data, compounds 1–3 and 7 have an ionic structure and consist of the organyltriphenylphosphonium cations with tetrahedral geometry of the phosphorus atoms and of the dicyanoaurate (1–3) or diiododicyanoaurate (7) anions with the linear or square planar geometry of the gold atoms, respectively. The crystal organization of compounds 2, 3, and 7 is caused by the interionic contacts С–H∙∙∙N≡C (2, 3, 7), O–H∙∙∙N≡C (7), and C–HPh∙∙∙π(C≡N) (2). In the case of complex 1, no significant interionic contacts have been observed in the crystal. Complete tables of atomic coordinates, bond lengths, and valence angles for compounds 1–3 and 7 are deposited in the Cambridge structural data Bank (no. 1978554 (1), 1965532 (2), 2060230 (3), 2060283 (7); deposit@ccdc.cam.ac.uk; http://www.ccdc.cam.ac.uk).