Binuclear copper(II) complexes containing phenols and catechols

The synthesis and characterisation of a series of binuclear copper(II) complexes of ligands formed by the condensation of substituted salicylaldehydes and 1,3-diamino-2-propanol (SalDplH(3)) and 1,5-diamino-3-pentanol (SalDpeH(3)) and their interaction with both phenols and catechols are reported. Spectroscopic and magnetic data suggest that the neutral phenols and catechols can bind to binuclear copper(II) complexes without actually coordinating to the copper atoms. The crystal and molecular structure of two binuclear copper(II) complexes have been solved. The mu-hydroxo bridged dicopper(II) complex of SalDpe(3-), [Cu(2)SalDpe(OH)], C19H20O4N2Cu2, I, having the space group P-1 and cell dimensions, a = 8.475(3), b = 15.727, c = 6.999(2) Angstrom, alpha = 99.51(2), beta = 92.84(3), gamma = 77.66(2)degrees was solved for 1839 structure factors (I>3.0 sigma(I)) and Z = 2, R = 4.2, R(w) = 4.3%. The compound consists of neutral molecules with an out-of-plane interaction from a copper in one binuclear unit to the hydroxo group of an adjoining molecule. The 4-ethylphenol adduct of the mu-(O,O') phenylacetate bridged dicopper(II) complex of SalDplH(3), [Cu(2)SalDpl(Phenac)(4-Ethylphenol)], C33H31N2O6Cu2, II having the space group P-1 and cell dimensions, a = 11.872(2), b = 13.418(3), c = 11.046(2) Angstrom, alpha = 101.95(2), beta = 103.65(1), gamma = 113.35(1)degrees was solved for 3833 structure factors (I>3.0 sigma(I)) and Z = 2, R = 4.1, R(w) = 4.3%. The 4-ethylphenol group is involved in a strong hydrogen bond to one of the phenolic oxygen donor atoms of the SalDpl(3-) ligand and a weaker hydrogen bond to the adjoining oxygen donor atom of the bridging phenylacetate ion. The other phenolic oxygen donor atom is involved in an out-of-plane interaction to one of the copper atoms.