Structural and magnetic variations in tetranuclear Ni^II clusters: the effect of the reaction solvent and ligand substitution on product identity

Abstract

Three structurally and magnetically different tetranuclear Ni(II) complexes have been isolated and magnetically characterized, emphasizing the effect of the reaction solvent and organic ligand substitution on the chemical identity of cluster compounds.

“Ligands-with-Benefits”: Naphthalene-Substituted Schiff Bases Yielding New NiII Metal Clusters with Ferromagnetic and Emissive Properties and Undergoing Exciting Transformations

“…[10][11][12] We have thus tried to understand the reasons of such coordination differences, which would also allow us to tentatively interpret the structural variations between the Ni II /nacb 2and Ni II /sacb 2products ( Figure S2). In all the reported Ni II /sacb 2compounds, [10][11][12] the ligand's phenyl rings are arranged in an average angle of ~47° from each other. However, the analogous average angle between the naphthalene and phenyl rings of nacb 2--related products is ~34°, significantly smaller than that of sacb 2-.…”

“…In contrast, the smaller angles between the aromatic rings of nacb 2allow the donor atoms of the ligand to interact differently with the metal ions and consequently stabilize compounds with different topologies than those seen in Ni II /sacb 2products. [10][11][12] Hence, the complete core of 1 (including only the doubly-bridging monoatomic groups) is [Ni12(μ-OR)20] 4+ (Figure 3) and can be conveniently described as four bent Ni3 units (Ni1-Ni2-Ni3, Ni4-Ni5-Ni6, etc., Figure S3) linked at each end by a μ-ORgroup (O8, O17, O26, O35) from a nacb 2-ligand. All Ni II atoms are six-coordinate with distorted octahedral geometries.…”

“…All Ni II atoms are six-coordinate with distorted octahedral geometries. The coordination spheres of Ni (1,4,7,10) are completed by a terminal H2O molecule; the latter are all strongly H-bonded to the non-bridging phenoxido O-atoms of nacb 2-. Finally, a space-filling representation ( Figure S4) shows the nanoscale dimensions of 1, with a diameter of ~25 Å and a central hole of ~7 Å diameter; note that the polar surface area of NHEt3 + is ~3.3 Å 2 , justifying its accommodation in the void space of the Ni12 wheel.…”

A Ni11 Coordination Cluster from the Use of the Di-2-Pyridyl Ketone/Acetate Ligand Combination: Synthetic, Structural and Magnetic Studies

“…This alignment, based on the above discussion, leads to the S = 3 ground state. In order to provide a qualitative explanation of the magnetic properties of 1, we assume as main interactions those provided by the monatomic oxygen bridges, which can be analyzed based on wellestablished magnetostructural correlations in nickel(II) complexes [11][12][13][14][15]18,[20][21][22]34,[39][40][41][42][43][44][45][46][47][48][49]. The linkage between the external cubanes and the central Ni3 subunit involves four Ni-O(hydroxido)-Ni units (Figure 3) with bond angles in the 117.1°-125.3°; these angles are expected to propagate antiferromagnetic exchange interactions.…”

“…This 3d 8 metal ion has shown promise in the synthesis of SMMs [7] and spin-phonon traps [10], with the former taking advantage of its significant single-ion anisotropy and the latter of its paramagnetic nature when the metal ion is confined in a highly symmetric cluster. These characteristics justify the interest of our groups in the chemistry of nickel(II) coordination clusters [11][12][13][14][15].…”