Unusual reactions of potassium dihalodicyanoaurates with organyltriphenylphosphonium halides

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).