Département de chimie moléculaire

Bis(azoliums) are readily available in one step from cyclic (alkyl)(amino)carbenes and bis(acyl chlorides). A two-electron redn. of the bis(azolium), featuring a gem-(dimethyl)malonoyl spacer, leads to the corresponding transient diradical, which undergoes an intramol. cyclization. The latter can be re-oxidized at a higher potential to yield back the bis(azolium). The redox bistability of this simple org. mol. system is linked to the formation of a weak C-O bond (27 kcal mol-1). Both redox forms can be isolated and stored for months without evidence of decay. [on SciFinder(R)]