Enneanuclear Ni(II) complexes from the use of the flexible ligand 2-pyridinealdoxime: The nature of the inorganic anion does not affect the chemical and structural identity of the cationic cluster

The use of 2-pyridinealdoximate(−1) [(py)CHNO−] in nickel(II) chemistry has been further investigated. The synthetic investigation has led to two new salts of the very recently reported (in the form of its tetraperchlorate salt, 1) enneanuclear cation [Ni9(μ3-OH)2(μ2-OH)2{μ3-(py)CHNO}4{μ2-(py)CHNO}6(μ2-OH2)2(H2O)6]4+. The two new cationic clusters [Ni9(OH)4{(py)CHNO}10(H2O)8](SCN)2(OH)2 · 9.91H2O (2 · 9.91H2O) and [Ni9(OH)4{(py)CHNO}10(H2O)8]{N(CN)2}3(ClO4) · 11.11H2O (3 · 11.11H2O) have been structurally characterized by single-crystal X-ray crystallography at 100 K. The nature of the inorganic anions (Cl−/SCN−,N(CN)2-/ClO4-) present in the reaction mixtures does not affect the chemical and structural identity of the enneanuclear cation. Characteristic IR data are discussed in terms of the nature of bonding and the structures of the complexes. The variable-temperature magnetic susceptibility data of 1, which had also been obtained by our group, were simulated by means of a 3-J model, which is compared with the 2-J model reported for this cluster by Chaudhuri and co-workers [S. Khanra, T. Weyhermüller, E. Rentschler, P. Chaudhuri, Inorg. Chem. 44 (2005) 8176]. The ground-state total spin of the cluster is ST = 1.

Graphical abstractThe synthetic investigation of the Ni2+/SCN−/N∩N–OH and Ni2+/N(CN)2-/ClO4-/N∩N–OH reaction systems leads to two new salts of the recently reported (in the form of the tetraperchlorate salt), thermodynamically stable (like the shown stone!) cation [Ni9(μ3-OH)2(μ2-OH)2(μ3-N∩N–O)4(μ2-N∩N–O)6(μ2-OH2)2(H2O)6]4+, where N∩N–OH is 2-pyridinealdoxime; the ground-state total spin of the clusters is ST = 1.Figure optionsDownload full-size imageDownload as PowerPoint slide