A insight into structural characterization, Hirshfeld surface analysis and DFT theoretical calculation of new hexanuclear Ni(II) complex containing two different coordination modes of N3- anions

A centrosymmetric hexanuclear Ni(II) complex [Ni-6(Py)(6)(mu(2)-eta(2)-N-3)(4)(mu(3)-eta(3)-N-3)(2)(mu(2)-OAc)(4)(mu(3)-CH3O)(2)(CH3OH)(2)] was synthesized via the reaction of the metal salts NaN3, Ni(CH3COO)(2)center dot 4H(2)O and the salamo-based ligand 6,6 '-di(tert-butyl)-2,2 '-[ethylenedioxybis(nitrilomethylidyne)]diphenol (H2L) in methanol/acetone/pyridine mixed solvents, respectively, and characterized by IR, UV-Vis and X-ray crystallography. X-ray analysis showed that the ligand H2L is not involved in the Ni(II) complex, but by the coordination of N-3(-) and CH3COO- anions, deprotonized methanol, pyridine and methanol molecules with Ni(II) atoms. All Ni(II) atoms are six-coordinated distorted octahedral geometries. Interestingly, N-3(-) anions possess two different coordination modes (mu(3)-eta(3)-N-3(-) and mu(2)-eta(2)-N-3(-)), and one of them (mu(3)-eta(3)-N-3(-)) has hardly appeared in previous reports. Hirshfeld surface analysis and DFT theoretical calculation were carried out to discuss the interaction and stability of the Ni(II) complex.