Copper(II) complexes of the antitumour-related ligand salicylaldehyde acetylhydrazone (H2L) and the single-crystal X-ray structures of [{Cu(HL)H2O}2] · 2(NO3) and [{Cu(HL) (pyridine) (NO3)}2]

Abstract

Binary and ternary copper(II) complexes of the ligand salicylaldehyde acetylhydrazone (H2L) have been prepared. In acid or neutral media monoanionic HL complexes separate. Addition of the Lewis bases pyridine (py) and thiourea (tu) to [{Cu(HL)H2O}2] · 2(NO3) results in the monoanionic ternary ligand adducts [{Cu(HL) (py) (NO3)}2] and [Cu(HL) (tu) (NO3)], respectively. With base, the le soluble dianionic complex [{CuL}2] was isolated. Addition of py to [{CuL}2]afforded the dianionic ternary complex [CuL(py)]· 1 2H2O. The complexes have been characterized by a range of physicochemical techniques and the crystal and molecular structures of [{Cu(HL)H2O}2] · 2(NO3) and [{Cu(HL) (py) (NO3)}2] determined. Crystals of [{Cu(HL)H2O}2] · 2 (NO3), C18H22Cu2N6O12, are monoclinic, with space group P21/c, a=7.217(4), b=11.758(8), c=13.764(8) A ̊, β=95.47(4)° and Z=4. [{Cu(HL)H2O}2] · 2 (NO3) is a centrosymmetric (planar) dimer, the monomeric units being bridged through the phenoxy oxygen. The copper atom has a square-pyramidal geometry with the basal donor atoms coming from the tridentate ligand (ONO) and the symmetry-related phenolate (O). The more weakly bound apical donor oxygen is supplied by a coordinated water molecule. The nitrate is not bound. Crystals of [{Cu(HL)(py) (NO3)}2], C28H28Cu2N8O10, are monoclinic, with space group P21/c, a=10.642(3), b=11.796(3), c=13.137(2) A ̊, β=111.03(2)° and Z=4. [{Cu(HL) (py) (NO3)}2] is a weakly interacting centrosymmetric (stacked) dimer, the monomeric units being bridged axially through the phenoxy oxygen. The copper atom has a tetragonal geometry with the equatorial donor atoms coming from the tridentate ligand (ONO) and the pyridine (N). The more weakly bound nitrato anion provides the other axial donor (O). Several of the complexes exhibit interesting magnetic properties. © 1995.