Copper(I)-mediated quaternisation of 1,4-diazabicyclo[2.2.2]octane (DABCO). Crystal structure of bis{(1-chloromethyl-4-aza-1-azoniabicyclo[2.2.2]octane)-μ-chloro-chlorocopper(I)}

Copper(I)-mediated quaternisation of 1,4-diazabicyclo[2.2.2]octane (DABCO) in dichloromethane solvent affords the dichloromethylated ligand, which has been isolated as the copper(I) complex bis{(1-chloromethyl-4-aza-1-azoniabicyclo[2.2.2]octane)-μ-chloro-chlorocopper(I)}. The crystal structure of the product, a discrete dimer [Cu2(μ-Cl)2Cl2(N(C2H4)3NCH2Cl)2], has been determined. A similar reaction in a mixture of diiodomethane and dichloromethane yields [C6H12N2(CH2I)]2(I3)I, the identity of which was also established by means of crystal-structure determination. The dimeric units of [Cu2(μ-Cl)2Cl2(N(C2H4)3NCH2Cl)2] are interconnected by short Cl⋯H interactions of 2.6 Å to form layers. This Cl⋯H interaction, which is the sole intermolecular contact of this magnitude, involves the terminal chloride bonded to copper(I).