Crystal structures of di-μ-chlorido-bis-({( E )-5-(ethyl-amino)-4-methyl-2-[(pyridin-2-yl)diazen-yl]phen-o-lato}copper(II)) and chlorido-bis-(1,10-phen-anthroline)copper(II) chloride tetra-hydrate

The dark-red title complex crystallized from an equimolar methanol solution of ( )-5-(ethyl-amino)-4-methyl-2-[(pyridin-2-yl)diazen-yl]phenol and CuCl (phen) (phen = 1,10-phenanthroline) as a centrosymmetric dimer, [CuCl(C H N O)] . The Cu atoms are bridged by two Cl ligands and have a slightly distorted square-pyramidal coordination, where two N atoms from the azo and the pyridine moieties, a phenolic O and a Cl atom comprise the base and the other Cl occupies the apex position. The apical Cu-Cl bond, 2.6192 (4) Å, is longer than the basal one, 2.2985 (3) Å, due to Jahn-Teller distortion. The dimers are associated weak inter-molecular hydrogen bonds and π-π stacking inter-actions between phenyl and pyridine rings. A monomeric by-product of the same reaction, [CuCl(phen) ]Cl·4H O, has a trigonal-bipyramidal coordination of Cu with equatorial Cl ligand, and extensive outer-sphere disorder. In the structure of , the packing of cations leaves continuous channels containing disordered Cl anions and solvent mol-ecules. The identity of the solvent (water or a water/methanol mixture) was not certain. The disordered anion/solvent regions comprise 28% of the unit-cell volume. The disorder was approximated by five partly occupied positions of the Cl anion and ten positions of O atoms with a total occupancy of 3, giving a total of 48 electrons per asymmetric unit, in agreement with the integral electron density of 47.8 electrons in the disordered region, as was estimated using the BYPASS-type solvent-masking program [van der Sluis & Spek (1990). A , 194-201].