Tetranuclear [{Ni(HL3)}{W(CN)8}]2 square: a case of antiferromagnetic {NiIIWV} interactions

Thengarai S. Venkatakrishnan (1) , Cédric Desplanches (2) , Raghunathan Rajamani (3) , Philippe Guionneau (2) , Laurent Ducasse (4) , S. Ramasesha (3) , Jean-Pascal Sutter (1)

1 LCC - Laboratoire de chimie de coordination
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 Solid State and Structural Chemistry
4 ISM - Institut des Sciences Moléculaires

A tetranuclear cyano-bridged [{Ni(HL3)}{W(CN)8}]2 compound in a square geometry was formed by self-assembling of {W(CN)8}3− and {NiL3}2+ (L3 = pentadentate ligand). The structure of the compound has been established by single crystal X-ray diffraction. The coordination sphere of the Ni ions is severely distorted with the macrocyclic ligand adopting a facial coordination with only four linkages to the metal center. The N atom of the pendant aminopropyl arm of L3 is no longer coordinated to the metal center but has undergone protonation during the assembling process. Magnetic measurements have revealed an unexpected antiferromagnetic behavior (J = −9 cm−1), which has been explained using a microscopic many-body electronic model Hamiltonian, based on DFT results. The many-body model is used to fit both the χMT versus T and the M versus H plots obtained from experiments.

Mots clés: Antiferromagnetism; DFT; Cyanometallate; Hamiltonian model

Domaines: Matériaux

Thengarai S. Venkatakrishnan, Cédric Desplanches, Raghunathan Rajamani, Philippe Guionneau, Laurent Ducasse, et al.. Tetranuclear [{Ni(HL3)}{W(CN)8}]2 square: a case of antiferromagnetic {NiIIWV} interactions. Inorganic Chemistry, 2008, 47 (11), pp.4854-4860. ⟨10.1021/ic800114y⟩. ⟨hal-00286936⟩