Synthesis and characterisation of four- and eight-membered ring auralactam complexes

Article abstract of DOI:10.1016/S0022-328X(00)00817-2

The reactions of the cyclo-aurated gold(III) dihalide complex [{C₆H₃(CH₂NMe₂)-2-(OMe)-5}AuCl ₂] with N-cyanoacety-lurethane [NCCH₂C(O)NHCO₂Et], 2-benzoylacetanilide [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, containing Au-NR-C(O)-CHR′ four-membered rings. A single-crystal X-ray diffraction study on the complex [{C₆H₄(CH₂NMe ₂)-2}Au{NPhC(O)CH(COMe)}] reveals similar structural features to related metallalactam complexes of platinum(II) and palladium(II). When a CDCl₃ solution of the complex [{C₆H₃(CH₂NMe ₂)-2-(OMe)-5}Au{N(CO₂Et)C(O)CHCN}] is allowed to stand for 18 h, a novel dimerisation reaction occurs, giving the insoluble product [{C₆H₃(CH₂NMe ₂)-2-(OMe)-5}Au{N(CO₂Et)C(O)CHCN}] ₂·2CDCl₃, characterised by an X-ray structure determination. The dimer contains an eight-membered Au-N-C(O)-C-Au-N-C(O)-C ring.