Protonated and deprotonated forms of nickel(II) complex with N-salicylidene-N'-(2-phenylimidazol-4-ylmethylidene)-1,3-propanediamine, 1 and 1', were synthesized and characterized. The X-ray crystal structures of 1 . H2O and 1' were determined: 1 . H2O, P2(1)/n (No. 14), a = 11.642(2), b = 12.908(3), c = 15.264(2) Angstrom, beta = 96.642(1)degrees; 1', I4(1)/a (No. 88), a = 22.651(3), c = 13.950(7) Angstrom. The crystal of 1 . H2O assumes a dinuclear structure bridged by the di-mu-phenoxo moiety in an out-of-plane fashion with Ni-Ni = 3.173(1) Angstrom and Ni-O = 2.126(3) Angstrom of the Ni2O2 core and two perchlorate ions as counter anions, in which the nickel(II) ion assumes an octahedral coordination geometry with N3O3 donor atoms consisting of four donor atoms of a quadridentate ligand, a bridging phenoxo-oxygen atom, and an oxygen atom of methanol. A ferromagnetic interaction with J = +7.1 cm(-1) operates between the two high-spin nickel(II) ions. 1 undergoes a deprotonation of the imidazole proton under basic conditions to give the deprotonated complex 1'. The crystal of 1' consists of an electrically-neutral imidazolate-bridged cyclic-tetranuclear molecule with Ni-Ni = 6.339(2) Angstrom and Ni-N = 2.051(7) Angstrom, in which the nickel(II) ion assumes a square-pyramidal geometry with N4O donor atoms consisting of the quadridentate ligand and an imidazolate nitrogen of the adjacent nickel(II) complex. An antiferromagnetic interaction with J = -6.3 cm(-1) is observed between the adjacent nickel(II) ions through the imidazolate group. Since the corresponding deprotonated copper(II) complex with the same ligand assumed an imidazolate-bridged zigzag-chain structure, the result with the nickel(II) complex demonstrates a very marked influence of the metal ion on the formation of the assembly structure.

Bis[(methanol)N-salicylidene-N '-(2-phenylimidazol-4-ylmethylidene)-1,3-propanediaminatonickel(II)] bridged by di-mu-phenoxo moiety and the deprotonated imidazolate-bridged cyclic-tetranuclear complex

RE, Nazzareno
1998-01-01

Abstract

Protonated and deprotonated forms of nickel(II) complex with N-salicylidene-N'-(2-phenylimidazol-4-ylmethylidene)-1,3-propanediamine, 1 and 1', were synthesized and characterized. The X-ray crystal structures of 1 . H2O and 1' were determined: 1 . H2O, P2(1)/n (No. 14), a = 11.642(2), b = 12.908(3), c = 15.264(2) Angstrom, beta = 96.642(1)degrees; 1', I4(1)/a (No. 88), a = 22.651(3), c = 13.950(7) Angstrom. The crystal of 1 . H2O assumes a dinuclear structure bridged by the di-mu-phenoxo moiety in an out-of-plane fashion with Ni-Ni = 3.173(1) Angstrom and Ni-O = 2.126(3) Angstrom of the Ni2O2 core and two perchlorate ions as counter anions, in which the nickel(II) ion assumes an octahedral coordination geometry with N3O3 donor atoms consisting of four donor atoms of a quadridentate ligand, a bridging phenoxo-oxygen atom, and an oxygen atom of methanol. A ferromagnetic interaction with J = +7.1 cm(-1) operates between the two high-spin nickel(II) ions. 1 undergoes a deprotonation of the imidazole proton under basic conditions to give the deprotonated complex 1'. The crystal of 1' consists of an electrically-neutral imidazolate-bridged cyclic-tetranuclear molecule with Ni-Ni = 6.339(2) Angstrom and Ni-N = 2.051(7) Angstrom, in which the nickel(II) ion assumes a square-pyramidal geometry with N4O donor atoms consisting of the quadridentate ligand and an imidazolate nitrogen of the adjacent nickel(II) complex. An antiferromagnetic interaction with J = -6.3 cm(-1) is observed between the adjacent nickel(II) ions through the imidazolate group. Since the corresponding deprotonated copper(II) complex with the same ligand assumed an imidazolate-bridged zigzag-chain structure, the result with the nickel(II) complex demonstrates a very marked influence of the metal ion on the formation of the assembly structure.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11564/290848
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