Synthesis and crystal structure of π-complex of copper(I) with 1-allylbenzimidazolium cation [C7H5N2H(C3H5)]+ [Cu3Cl4

Abstract

Single crystals of [C7H5N2H(C3H5)]+[Cu3Cl4]− were obtained for the first time by ac electrochemical synthesis from 1-allylbenzimidazolium and copper(II) chlorides in ethanol and structurally characterized. The unit cell parameters are a=8.6755(9) A, b=8.846(1) A, c=10.4540(7) A, α=85.36(1)°, β=70.529(7)°, γ=83.29(1)° , V=750.5(3) A3, space group P\(\bar 1\), R(F)=0.0551. In the π-complex, the copper and chlorine atoms form complicated infinite chains along the x axis. The 1-allylbenzimidazolium cation functions as an original bridge: it is coordinated by the Cu atom of one cuprous-chloride chain through the C=C bond of the allyl group and forms a N-H⋅⋅⋅Cl hydrogen bond with another inorganic chain through the N atom of the imidazole ring. The trigonal pyramidal environment of the Cu(1) atom includes three Cl atoms and the C=C bond; the environments of the Cu(2), Cu(3), and Cu(3a) are composed only of chlorine atoms. The positions of the Cu(2) and Cu(3a) atoms are partially disordered, which is manifested by the high thermal parameters for the Cu(2) atom and by the splitting of another copper atom into two equally occupied positions Cu(3) and Cu(3a).