Stable ‐ESiMe 3 Complexes of Cu I and Ag I (E=S, Se) with NHCs: Synthons in Ternary Nanocluster Assembly

As a part of efforts to prepare new “metallachalcogenolate” precursors and develop their chemistry for the formation of ternary mixed‐metal chalcogenide nanoclusters, two sets of thermally stable, N‐heterocyclic carbene metal–chalcogenolate complexes of the general formula [(IPr)Ag−ESiMe 3 ] (IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene; E=S, 1 ; Se, 2 ) and [( i Pr 2 ‐bimy)Cu−ESiMe 3 ] 2 ( i Pr 2 ‐bimy=1,3‐diisopropylbenzimidazolin‐2‐ylidene; E=S, 4 ; Se, 5 ) are reported. These are prepared from the reaction between the corresponding carbene metal acetate, [(IPr)AgOAc] and [( i Pr‐bimy)CuOAc] respectively, and E(SiMe 3 ) 2 at low temperature. The reaction of [(IPr)Ag−ESiMe 3 ] 1 with mercury(II) acetate affords the heterometallic complex [{(IPr)AgS} 2 Hg] 3 containing two (IPr)Ag−S − fragments bonded to a central Hg II , representing a mixed mercury–silver sulfide complex. The reaction of [( i Pr 2 ‐bimy)Cu‐SSiMe 3 ] 2 , which contains a smaller N‐heterocyclic‐carbene, with mercuric(II) acetate affords the high nuclearity cluster, [( i Pr 2 ‐bimy) 6 Cu 10 S 8 Hg 3 ] 6 . The new N‐heterocyclic carbene metal–chalcogenolate complexes 1 , 2 , 4 , 5 and the ternary mixed‐metal chalcogenolate complex 3 and cluster 6 have been characterized by multinuclear NMR spectroscopy ( 1 H and 13 C), elemental analysis and single‐crystal X‐ray diffraction.