Synthesis and characterisation of four- and eight-membered ring auralactamcomplexes

The reactions of the cyclo-aurated gold(III) dihalide complex [{C6H3(CH2NMe 2)-2-(OMe)-5}AuCl2] with N-cyanoacetylurethane [NCCH2C(O)NHCO2Et], 2-benzoy lacetanilide [PhC(O)CH2C(O)NHPh] and acetoacetanilide [MeC(O)CH2C(O)NHPh], and [{C6H4(CH2NMe2)-2)AuCl2] with acetoacetanilide in dichloromethane with excess silver(I) oxide gives the first examples of auralactam complexes, co ntaining Au-NR-C(O)-CHR' four-membered rings. A single-crystal X-ray diffra ction study on the complex [{C6H4(CH2NMe2)-2}Au{NPhC(O)6H(COMe)}] reveals s imilar structural features to related metallalactam complexes of platinum(I I) and palladium(II). When a CDCl3 solution of the complex [{C6H3(CH2NMe2)- 2-(OMe)-5}Au{N(CO2Et)C(O)CHCN}] is allowed to stand for 18 h, a novel dimer isation reaction occurs, giving the insoluble product [{C6H3(CH2NMe2)-2-(OM e)-5}Au(N(CO2Et)C(O)CHN}](2). 2CDCl(3), characterised by an X-ray structure determination. The dimer contains an eight-membered Au-N-C(O)-C-Au-N-C(O)- C ring. (C) 2001 Elsevier Science B.V. All rights reserved.