Reactivity of [2,6-Bis((dimethylamino)methyl)phenyl]gold(I), an Unusual Intermolecularly Stabilized Bis(amino)aryl−Gold(I) Dimer, toward Alkyl Halides. X-ray Crystal Structures of Its Iodomethane and Methylene Diiodide Adducts

Novel [2,6-bis((dimethylamino)methyl)phenyl]gold(I) dimer ( 4 ) was prepared in 60% yield from [AuCl(tht)] (tht = tetrahydrothiophene) and [2,6-bis((dimethylamino)methyl)phenyl]lithium. Compound 4 is a rare example of a dimeric organogold(I) species involving intermolecular gold(I)−N(sp 3 ) coordination. Variable-temperature NMR points to the formation of a 10-membered ring and provides evidence for the occurrence of a boat−chair ring conformation equilibrium. Reaction of 4 with MeI affords the unexpected heteroaurate(I) [Au(C 6 H 3 {CH 2 NMe 3 } 2 -2,6)I]I ( 5 ) by Me transfer to the nitrogen atom of the ortho amino ligand. The molecular structure of 5 was elucidated by means of X-ray analysis. Conversely, the reaction of 4 with CH 2 I 2 afforded the organogold(III) complex [Au(C 6 H 3 {CH 2 NMe 2 }-2-{CH 2 N(Me) 2 CH 2 }-6)I]I ( 6 ), containing a methylene fragment bridging a Au(III) center and a quaternary N center, as confirmed by a single-crystal X-ray diffraction study. A mechanistic pathway involving prior coordination of the alkyl halide to gold(I) followed by oxidative addition and alkyl transfer is proposed to account for the formation of both 5 and 6 .