Architecture of framework copper(I) halide π-complexes with N-allyl-N,N,N',N'-tetramethyl-ethylenediaminium and N,N'-diallyl-N,N,N',N'-tetramethylethylenediaminium: Synthesis and crystal structure of [{C2H4N2(H+)x(CH3)4(C3H5)} Cu4Cl6] and [{C2H4N2(CH3)4(C3H5)2}0.5Cu2Cl1.67Br1.33]

N,N,N',N'-tetramethylethylenediamine is obtained by the reaction of ethylenediamine with formaldehyde and formic acid (the Eschweiler-Clarke reaction) and then alkylated with allyl chloride (or bromide) in a ratio of 1:1 or 1:2 to obtain N-allyl-N,N,N',N'-tetramethylethylenediaminium and N,N'-diallyl-N,N,N',N'-tetramethylethylenediaminium bromide respectively. [{C2H4N2(H+)(CH3)(4)(C3H5)}Cu4Cl6] (1) and [{C2H4N2(CH3)(4)(C3H5)2}(0.5)Cu2Cl1.67Br1.33] (2) pi-complexes are obtained from alcohol solutions containing an ethylenediamine derivative and copper(II) chloride by ac-electrochemical synthesis on copper wire electrodes. An XRD study of the complexes is carried out. The crystals are monoclinic; 1: P2(1)/n space group, a = 9.0081(6) , b = 12.5608(7) , c = 16.8610(10) , beta = 102.061(3)A degrees, V = 1865.7(2) (3), Z = 4; 2: C2/c space group, a = 14.462(2) , b = 12.519(1) , c = 12.762(2) , beta = 107.861(5)A degrees, V = 2199.1(4) (3), Z = 8. The structure of 1 consists of infinite copper halide networks with four crystallographically independent copper atoms, one of which coordinates the double bond of the allyl group of the ligand. The [C2H4N2(H)(CH3)(4)(C3H5)](2+) cations are attached above and below the plane of the network. The individual fragments are bonded via an extensive system of (N)HaEuro broken vertical bar Cl and (C)HaEuro broken vertical bar Cl hydrogen bonds. The structure of 2 contains a three-dimensional copper halide framework whose cavities contain the [C2H4N2(CH3)(4)(C3H5)(2)](2+) cations that are pi-coordinated with copper(I) atoms. In both structures, the Cu(I) atom that coordinates the C=C bond has a trigonal-pyramidal coordination environment consisting of the double C=C bond of the corresponding ligand and three halogen atoms. The other Cu(I) atoms have a tetrahedral environment consisting solely of halogen atoms. The Cu-(C=C) distance is 1.958(1) , (1) and 1.974(1) (2).