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

Abstract

The reactions of the cyclo-aurated gold(III) dihalide complex [{C 6H 3(CH 2NMe 2)-2-(OMe)-5}AuCl 2] with N-cyanoacetylurethane [NCCH 2C(O)NHCO 2Et], 2-benzoylacetanilide [PhC(O)CH 2C(O)NHPh] and acetoacetanilide [MeC(O)CH 2C(O)NHPh], and [{C 6H 4(CH 2NMe 2)-2}AuCl 2] 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 [{C 6H 4(CH 2NMe 2)-2}A u{NPhC(O)C H(COMe)}] reveals similar structural features to related metallalactam complexes of platinum(II) and palladium(II). When a CDCl 3 solution of the complex [{C 6H 3(CH 2NMe 2)-2-(OMe)-5}A u{N(CO 2Et)C(O)C HCN}] is allowed to stand for 18 h, a novel dimerisation reaction occurs, giving the insoluble product [{C 6H 3(CH 2NMe 2)-2-(OMe)-5}Au{N(CO 2Et)C(O)CHCN}] 2·2CDCl 3, characterised by an X-ray structure determination. The dimer contains an eight-membered A uNC(O)CAuNC(O)C ring.