New N-heterocyclic carbene silver(I) and mercury(II) 2-D supramolecular layers by the π–π stacking interactions

The precursor 1-(9-anthracenylmethyl)-3-alkylbenzimidazolium chlorides (1a, alkyl = C4H9, 1b, alkyl = C6H13) and their three new NHC silver(I) and mercury(II) complexes {[1-(9-anthracylmethyl)-3-alkylbimy]MCl}2 (2a, alkyl = C4H9, M = Ag; 2b, alkyl = C6H13, M = Ag; 3a, alkyl = C4H9, M = Hg; bimy = benzimidazol-2-ylidene) have been prepared and characterized. The crystal structures of 2a, 2b and 3a showed that 2-D supramolecular layers are formed by both benzimidazole ring head to tail π–π stacking interactions and anthracene ring face-to-face π–π stacking interactions.