SYNTHESIS, CHARACTERIZATION AND CRYSTAL-STRUCTURE OF A NOVEL TRIS(2-AMINOETHYL)AMINE COPPER(II) COMPLEX WITH AN ASYMMETRIC COORDINATED 4,5-DIAZAFLUORENE-9-HYDRAZINE

The compound, s(2-aminoethyl)amine-4,5-diazafluorene-9-hydrazine coppe r(II) perchlorate complex, [Cu(C6H18N4)(C11H8N4)](ClO4)(2) (1), has be en designed, synthesized and characterized. The X-ray analysis reveals that the copper(II) is coordinated by four nitrogen atoms from tris(2 -aminoethyl) amine (tren) and two nitrogen atoms from 4,5-diazafluoren e-9-hydrazine (dzfh) to form an unusual (4+1+1') six-coordinate geomet ry. This structure is very rare, and to our knowledge, is a unique exa mple of a tripodal copper(II) complex with an asymmetric bidentate phe nanthroline derivative. The 110 K ESR and electronic reflectance spect ra studies demonstrate that the coordinated geometry of copper(II) is quite similar to square-based pyramidal stereochemistry, instead of th e trigonal bipyramidal stereochemistry, which is the common structure for [Cu(tren)L](2+) (L = monodentate ligand) complexes. The electronic and variable-temperature ESR spectra in absolute DMF suggest that the two nitrogen atoms of the dzfh coordinate to the copper(II) ion in th e two-dimensional fluxional model. For comparison, the complex, Cu(tre n)(Py)(ClO4)(2) (Py is pyridine) (2), was also synthesized and charact erized. Copyright (C) 1996 Elsevier Science Ltd