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(l)-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(l) complex bis ({1-chloromethyl-4-aza-1-azoniabicyclo[2.2.2]octane)-mu-chloro-chlorocopper(I)}. The crystal structure of the product, a discrete dimer [Cu-2(mu-Cl)(2)Cl-2(N(C2H4)(3)NCH2Cl)(2)], has been determined. A similar reaction in a mixture of diiodomethane and dichloromethane yields [C6H12N2(CH2I)](2)(I-3)I, the identity of which was also established by means of crystal-structure determination. The dimeric units Of [Cu-2(mu-Cl)(2)Cl-2(N(C2H4)(3)NCH2Cl)(2)] are interconnected by short Cl...H interactions of 2.6 angstrom to form layers. This Cl...H interaction, which is the sole intermolecular contact of this magnitude, involves the terminal chloride bonded to copper(l). (c) 2004 Elsevier B.V. All rights reserved.