Fig. 5. Reactivity of the hypercarbon in CAu^I₅ clusters.

a Reaction of SS-(or RR-)2^NHC with (tht)Au^ICl (tht = tetrahydrothiophene) yielded Cl-coordinated CAu^I₆ clusters: SS- and RR-4^NHC [(C)(Au^I-L)₅(Au^ICl)](BF₄) (L = SS- and RR-NHC). b The SCXRD structure of the [(C)(Au^I-SS-NHC)₅(Au^ICl)]⁺ cation and the Cl-coordinated CAu^I₆ core in SS-4^NHC. The arrangement of three grey-coloured benzimidazolylidene moieties on the same plane and two orange-coloured benzimidazolylidene moieties on two planes in SS-4^NHC is similar to that in SS-2^NHC (Suppl. Fig. 37). Colour code: Au, yellow and orange; C, grey; N, blue; Cl, green. Hydrogen atoms, BF₄^– counterion, and solvent molecules are omitted for clarity.