Synthesis, structures and dielectric properties of two five-coordinate copper (II) complexes based on N-chloromethyl-1, 4-diazabicyclo[2.2.2]octane

Two novel five-coordinate metal-organic-inorganic complexes Cu(LCH2Cl)Cl3H2O (1) and [Cu(LCH2Cl)2Cl2](ClO4)2 (2) (L+CH2Cl = N-chloromethyl-1,4-diazabicyclo[2.2.2]octonium ion) were prepared with two different geometries. Compound 1 displays 1D chain structure cross-linked by hydrogen bonds, compound 2 displays 0D layer structure with disorder-order transition of ClO4− anions at different temperatures. Different structures lead to large discrepancy in the frequency and temperature dependence of the dielectric constant measurements.