Investigation of the composition space diagram CuCl–allylamine–dabco. A new mixed ligand compound of (H2dabco)2[Cu4Cl9(allNH3)] composition with unique Cu4Cl95– cupro(I)-chloride fragment

Abstract

The ternary system CuCl–allylamine–dabco (dabco = 1,4-diazabicyclo[2.2.2]octane) with an excess of HCl was explored. Starting from an ethanol solution of CuCl₂·2H₂O, allylamine and dabco titrated with HCl, copper(I) salts were generated by means of electrochemical alternating current synthesis. In addition to the already known (H₂dabco)[CuCl₃], two modifications of the (allNH₃)₂[Cu₂Cl₄] compound and some Cu(II) by-products, a new mixed ligand compound of the composition (H₂dabco)₂[Cu₄Cl₉(allNH₃)] was synthesized and structurally investigated. Its structure contains unique Cu₄Cl₉^5– inorganic moiety bound via a h₂-interaction allylammonium moiety and discrete (H₂dabco)²⁺ cations. The structure is stabilized by the system of N–H···Cl hydrogen bonds.