Two new nickel(II) cubane compounds derived from pyridine-2-methoxide (Pym): {Ni-4(Pym)(4)Cl-4(CH3OH)(4)} and {Ni-4(Pym)(4)(N-3)(4)(CH3OH)(4)}. Crystal structures and magnetic properties

The pyridine-2-methoxide anion (Pym) allows the two new nickel(II) cubane c ompounds: {Ni-4(Pym)(4)Cl-4(CH3OH)(4)} (1) and {Ni-4(Pym)(4)(N-3)(4)(CH3OH) (4)} (2), to be easily synthesized. 1 and 2 are structurally characterised. Complexes 1 and 2 crystallise in the tetragonal system. 1 and 2 have simil ar structures that consist of tetrameric cubane complexes with the alkoxide oxygen atoms of the pyridine-2-methoxide ligand and octahedrally co-ordina ted nickel(II) atoms placed alternately at the corners of the cube. Magneti c susceptibility data, measured from 2 to 260 K show ferromagnetic behaviou r for 1 and 2. These data were fitted by using the equation derived from th e Hamiltonian H = -2J(1)(S1S2 +S3S4)-2J(2)(S1S3 + S1S4 + S2S3 + S2S4) inclu ding the Zero Field Splitting for the ground stare S = 4, giving the parame ters J(1) = 0.43, J(2) = 5.28, D = -0.47 cm(-1), g = 2.11 for 1 and J(1) = 9.78, J(2) = 2.42, D = -0.10 cm(-1), g = 2.21 for 2. (C) 1999 Elsevier Scie nce Ltd. All rights reserved.