The case of symmetry-dependent ground-state spin value in Ni(II) clusters of high-nuclearity. Crystal structure and magnetic properties of a pentanuclear and a nonanuclear Ni(II) clusters

The crystal structures and the magnetic properties of a pentanuclear (1) an d a nonanuclear (2) Ni(II) clusters are described. In the former, crystalli zing in the cubic I23 space group, the Ni(II) assembly is composed of a reg ular tetrahedral geometry of four metal ions centered on the fifth. The non anuclear cluster crystallizes in the hexagonal crystallographic system - R3 space group - the Ni(II) assembly is composed of two regular tetrahedra, l ike that of the pentanuclear cluster, sharing a common apex. All metal ions in either cluster are six-coordinate. Variable-temperature magnetic suscep tibility data show antiferromagnetic interactions for both clusters. Moreov er, magnetization data are in line with uneven intermediate-spin ground sta tes [S=1, S=2] and [S=2, S=3] for 1 and 2, respectively. A comparison of bo th the symmetry and the spin ground state of 1 to those of lower-symmetry p entanuclear Ni(II) clusters, reveals that the ground-state spin value incre ases with the cluster symmetry.