4-COORDINATE AND 5-COORDINATE DINUCLEAR COPPER(II) COMPLEXES WITH THE TETRAACETYLETHANEDIIDE AND AN N-ALKYLATED DIAMINE OR A TRIAMINE

Six dinuclear copper(II) complexes have been prepared, Cu-2(taet)(plam)(2)X(2) where taet = 1,1,2,2-tetraacetylethanediide, plam = N-alkylated polyamine such as tmen = N,N,N',N'-tetramethylethylenediamine or pmdt = N,N,N',N'',N''-pentamethyldiethylenetriam X = a monovalent anion such as ClO4-, NO3- or Cl-. These complexes are classified into two categories from the results of electronic spectra, IR spectra, and X-ray single crystal structure analysis as follows: (1) 4-coordinate-4-coordinate dinuclear, [Cu-2(taet)(tmen>2]X(2) (where X = ClO4- or NO3-), (2) 5-coordinate-5-coordinate dinuclear, [Cu-2(taet)(tmen)(2)Cl-2], and [Cu2(taet)(pmdt)(2)]X(2) (where X = ClO4-, NO3-, or Cl-). The crystal structure of Cu-2(taet)(tmen)(2)(ClO4)(2) . H2O (1) has been determined by the single crystal X-ray diffraction technique; monoclinic space group P2(1)/a with a = 26.478(3), b = 8.744(1), c = 15.601(3) Angstrom, beta = 106.195(9)degrees and V = 3468.9(8) Angstrom(3) for Z = 4. The final agreement factors are R = 0.097 (R(w) = 0.099). The geometry of each Cu(II) moiety in the dinuclear cation (1) is 4-coordinate square planar with a N2O2 donor set. This tmen-dinuclear complex exhibits a very weak Cu(II)-Cu(II) interaction (J = -0.5 cm(-1)), and shows characteristic ESR spectra with seven hyperfine peaks in 1,a-dichloroethane solution at room temperature. This is not found for the corresponding pmdt-dinuclear complex. All complexes obtained in this study are very soluble in many organic solvents. The tmen-dinuclear complexes show pronounced solvatochromic behavior-dependent on the solvent donor properties. This is not found for the corresponding pmdt-dinuclears, which are stable as 5-coordinated species.