A ferromagnetically coupled single hydroxido bridged tetranuclear nickel(II) Schiff base complex incorporating a Ni4O4 cubane core: crystal structure and magnetic study

Shyamapada Shit, Madhusudan Nandy, Georgina Margaret Rosair, Carlos J Gómez-García, Juan J Borras Almenar, Samiran Mitra

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21 Citations (Scopus)

Abstract

The new tetranuclear nickel(II) complex [Ni-4(OH)(L)(HL)(2)(CH3OH)(1.5)(H2O)(1.5)]center dot 9H(2)O (1) has been synthesised by the reaction of NiCl2 center dot 6H(2)O and the Schiff base ligand H3L (H3L = (CH3O)(OH)C6H3CH=N-C(CH3) (CH2OH)(2)), prepared by the 1:1 condensation of 2-amino-2-methyl-1,3-propanediol and o-vanillin, and characterized by different physicochemical methods. Single crystal X-ray structural determination identifies a Ni4O4 cubane moiety as the central part of the complex unit. The presence of a single mu(3)-hydroxido bridged oxygen occupying only one vertex of the Ni4O4 cubane core is rare in Ni4O4 cubanes (ca. 5% of occurrence). Structural analysis also reveals two similar alkoxido oxygen atoms of the Schiff base coordinating the metals in two different modes; one in the mu(3)-bridging mode whilst the other binds in a monodentate fashion. The metal centers display distorted octahedral geometries with two different coordination environments. The magnetic properties reveal the presence of ferromagnetic nickel(II)-nickel(II) interactions in the cluster with two different exchange pathways. The magnetic data can be fitted to a Ni4O4 cubane model with g = 2.058, J(1) = +17.2 cm(-1) and J(2) = +6.6 cm(-1). Isothermal magnetization measurements confirm the S = 4 spin ground state. Both J values agree with previous magneto-structural correlations in doubly oxido-bridged nickel(II) complexes. (C) 2013 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)73-79
Number of pages7
JournalPolyhedron
Volume61
DOIs
Publication statusPublished - 18 Sep 2013

Keywords

  • Nickel(II) Schiff base complex
  • Characterization
  • X-ray structure
  • Cubane core
  • Single mu(3)-hydroxido bridge
  • Ferromagnetic coupling
  • NEUTRON-SCATTERING SPECTRA
  • SPIN CLUSTERS
  • MAGNETOSTRUCTURAL CORRELATIONS
  • ENERGY-LEVELS
  • GROUND-STATE
  • LIGAND
  • TEMPERATURE
  • NUCLEARITY
  • EXCHANGE
  • BEHAVIOR

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