Monoprotic Tetradentate N(3)O-Donor Ligands and Their Cu(II) and Ni(II) Complexes.

A convenient four-step procedure was developed to prepare the novel monoprotic tetradentate ligands N-(2-hydroxy)benzyl-N-methyl-N'-(2-pyridyl)methyl-1,3-propanediamine (Hpamap) and N-(2-hydroxy)benzyl-N'-methyl-N'-(2-pyridyl)methyl-1,3-propanediamine (Hpmaap), which provide an N(3)O metal coordination sphere. A mononuclear copper(II) complex, [Cu(pamap)Cl] (A), was obtained by reaction of Hpamap with CuCl(2).2H(2)O. The binuclear copper(II) complexes Cu(pamap)(BF(4))(2) (B) and Cu(pmaap)(BF(4))(2) (C) were obtained when these ligands were reacted with Cu(II) in the presence of the noncoordinating BF(4)(-) anion. Reaction of nickel(II) with the Hpamap ligand generated the binuclear Ni(II) complex [Ni(2)(pamap)(2)(NO(3))]NO(3) (D). The crystal of A (C(17)H(22)ClCuN(3)O) is orthorhombic Pbca (No. 61), a = 11.837(4) Å, b = 15.648(5) Å, c = 11.002(11) Å, Z = 8; that of B (C(34)H(44)B(2)Cu(2)F(8)N(6)O(2)) is triclinic P&onemacr; (No. 2), a = 9.147(0) Å, b = 10.375(0) Å, c = 10.535(1) Å, alpha = 107.20(0) degrees, beta = 91.19(0) degrees, gamma = 105.05(0) degrees, Z = 1; that of C (C(34)H(44)B(2)Cu(2)F(8)N(6)O(2)) is monoclinic P2(1)/c (No. 14), a = 9.158(2) Å, b = 10.714(2) Å, c = 19.085(4) Å, beta = 90.58(2) degrees, Z = 4; and that of D (C(34)H(44)N(8)NiO(8)) is monoclinic C2/c (No. 15), a = 13.849(0) Å, b = 13.609(0) Å, c = 19.558(1) Å, beta = 92.34 (0) degrees, Z = 4. The copper atoms of all three complexes are five-coordinate in the solid state, assuming the geometry of a distorted square pyramid with the deprotonated tetradentate ligand in the basal plane. The mononuclear complex A has a chloride ligand in the axial position, while each copper center in the binuclear complexes B and C has, in the axial position, a bridging phenolate O donor from the other unit of the dimer. Each nickel center in the binuclear complex D is six-coordinate, with the pseudo-octahedron formed by a deprotonated tetradentate ligand, a bridging nitrato oxygen atom, and a bridging phenoxy donor from the tetradentate ligand bound to the second nickel center.