Synthesis, structure and transmetalation of N-heterocyclic carbene complex of silver. Evidence of halogen exchange during the synthetic processCCDC reference numbers 736323 (1), 736324 (2), 736325 (3) and 736326 (4). For crystallographic data in CIF or other electronic format see DOI: 10.1039/b911886a

Deprotonation of the bis(imidazolium) salt (1,1′-dimethyl-3,3′-ethylenediimidazolium dibromide, L·2HBr) with silver oxide in a solution mixture of CH2Cl2and CH3OH affords a silver carbene complex [Ag2L2]Cl2(1, L = 1,1′-dimethyl-3,3′-ethylenediimidazol-2-ylidene). With CH3OH as the only solvent for the synthesis and after recrystallization in a chlorinated solvent in ambient condition, a polymeric silver complex [(L·2H)(Ag2Br4)]n(2) was formed. The presence of chloride in complex 1and bromide in complex 2indicates that a halogen exchange reaction occurred unambiguously during the synthesis and not during recrystallization. The silver-carbene complex 1undergoes a facile reaction with [(p-cymene)RuCl2]2and (p-cymene)Ru[S2C2(B10H10)] to yield the binuclear complexes [(p-cymene)RuCl2]2L (3) and {(p-cymene)Ru[S2C2(B10H10)]}2L (4). The latter compound contains a carbene ligand and a 1,2-dicarba-closo-dodecaborane ligand. Molecular structures of complexes 1–4were confirmed by X-ray single-crystal analyses. [ABSTRACT FROM AUTHOR]