Sinthesis and molecular structure of novel dihalogenodicyanoaurate complexes

Interaction of tetraorganylphosphonium halides with potassium dichloro-, dibromo- and diiododicyanoaurate in water followed by recrystallization from acetonitrile has been used to synthesize gold(III) ionic complexes [Me4P][Au(CN)2Cl2] (1), [Ph3PR][Au(CN)2Hal2] (Hal = Cl, R = (CH2)6Me (2), (CH2)2C(O)OH (3); Hal = Br, R = CH2CN (4); Hal = I, R = CH2CN (5)) and [Ph3PCH=CHPPh3][Au(CN)2Cl2]2 (6). In a similar way complex [Ph4Sb][Au(CN)2Cl2] (7) has been obtained by the interaction of tetraphenylantimony chloride with potassium dichlorodicyanoaurate. Complexes 3, 5-7 have been structurally characterized by the X-ray analysis method. According to the X-ray data phosphorus and antimony atoms in crystals 3, 5-7 have a slightly distorted tetrahedral coordination (the CPC bond angles are 107.5(2)-111.8(3)° (3), 106.0(3)-111.5(3)° (5), 106.7(4)-111.8(4)° (6), the CSbC bond angles are 100.5(7)-114.6(5)° (7); the P-C bond lengths are 1.788(5)-1.807(5) Å (3), 1.765(6)-1.821(6) Å (5), 1.781(8)-1.810(8) Å (6); the Sb-C bond lengths are 2.070(11)-2.121(12) Å (7)). Gold atoms in [Au(CN)2Hal2]- anions have a slightly distorted square planar coordination (the HalAuHal and CAuC trans -angles are quite close to 180°; the CAuHal cis -angles vary from 88.05° to 92.48°), the Au-Hal bond lengths are 2.328(3) Å (3), 2.393(2), 2.411(2) Å (6), 2.4223(12) Å (7) for Au-Cl and 2.609(3), 2.598(3) Å (5) for Au-I; the Au-C bond lengths are 1.981(7) Å (3), 1.996(7), 2.006(8) Å (5), 1.978(12), 2.001(13) Å (6), 2.040(15) (7). In crystal 5 two types of crystallographically independent centrosymmetric [Au(CN)2I2]- anions are observed. The structural organization of complexes 3, 5-7 is caused by the different noncovalent interactions: С-H∙∙∙N≡C 2.55-2.74 Å (3, 5-7), O-H∙∙∙N≡C 2.03 Å, С-H∙∙∙O=C 2.52 Å, C-H∙∙∙Cl-Au 2.88-2.93 Å (3), Au-I∙∙∙I-Au 3.925(4) Å (5), C-H∙∙∙Cl-Au 2.91 Å (6).