Tetranuclear [{Ni(HL³)}{W(CN)₈}]₂ Square: A Case of Antiferromagnetic {Ni^IIW^V} Interactions

Abstract

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 chiMT versus T and the M versus H plots obtained from experiments.

Further Insights into the Role of Temperature in the Synthesis of the Lanthanide(III)‐Pyrazine‐Octacyanotungstate(V) System: an Example of Discrete Materials

“…To the best of our knowledge, compounds 1 and 2 represent the first structurally characterized examples of discrete octacyanometalate-based lanthanide molecular squares, although several transition metal compounds based on octacyanometalates building blocks with discrete square structures have been documented so far, most of which consists of an anionic square core co-crystallized with a charge-balance cation. [16,17,[22][23][24][25][26] Terminal cyanide ligands, coordinated and uncoordinated water molecules, and CH 3 CN solvents are all involved in the well-defined hydrogen-bonding network (Table 4, Table 5). Six terminal CN groups interact with coordinated and lattice H 2 O molecules through the O-H···N hydrogen bonds.…”

Phototunable Magnetism in Copper Octacyanomolybdate

“…On the other hand, the direct Cu-Cu exchange interaction J CuCu is taken to be negative. The magnitude of the exchange interactions in the transfer-integral unit is comparable to that in typical cyano-bridged transition-metal complexes [37–39]. The pair-hopping correlation J MoCu ′ set positive indirectly supports FM, destabilizing any other phase [27].…”

A Decade of Octacyanides in Polynuclear Molecular Materials

“…The star‐like clusters are achieved when a polydentate blocking ligand leaves only one coordination site for cyanide bridging and were so far obtained only with octacyanomolybdate (IV) as a centre. Among the clusters comprising two octacyanometallate ions, the most common are squares,42,52–59 but trigonal60 and tetragonal bipyramids13,59,61,62 are also observed (Figure 3a, b). They are usually formed when an octahedral cationic complex includes two bidentate ligands like bpy or phen and has two cis positions available for bridging.…”