CRYSTAL-STRUCTURE AND EPR-SPECTRUM OF DIMERIC S[CYANIDE(N,N-DIETHYLETHYLENEDIAMINE)]-COPPER(II), [CU(N-3)(NCO)(DIETEN)](2)

The title compound, [Cu(N-3)(NCO)(C6H16N2)](2), crystallizes in the sp ace group P2(1)/n, with a = 8.336(1), b = 17.405(3), c = 8.376(1) Angs trom, beta = 109.73(2)degrees and Z = 4. The molecules are arranged as centrosymmetric dimers in which two azide ligands bridge neighboring copper ions in an asymmetric head-on fashion. The Cu(II) ion is coordi nated to five nitrogen atoms which form a distorted tetragonal pyramid . At the pyramid base are the two N atoms of a diEten molecule [Cu-N = 2.00(1), 2.130(9) Angstrom], an azide end atom [Cu-N = 1.99(1) Angstr om] and a NCO group [Cu-N = 1.93(1) Angstrom]. At the pyramid apex is the other, inversion related, azide N atom in the dimer [Cu-N = 2.38(1 ) Angstrom]. This Cu-N contact links the monomers within a dimer. Neig hboring dimers are coupled by weak N-H...O contacts. Single crystal EP R data at X-band show that the pair of resonances expected for neighbo ring, magnetically nonequivalents dimers, collapse into a single line, a signature of inter-dimers superexchange coupling. The observed crys tal gyromagnetic tensor is used to disclose the electronic and magneti c structure around Cu(II) ions.