Three p-tert-butylthiacalix[4]arene-supported cobalt compounds obtained in one pot involving in situ formation of N6H2 ligand.

Three p-tert-butylthiacalix[4]arene (H(4)TC4A)-supported Co(II) compounds, Co(4)(TC4A)(N(3))(4)(N(6)H(2))(CH(3)OH)(2) (1), Co(8)(TC4A)(2)(N(3))(2)(N(6)H(2))(2)(CH(3)COO)(4)(CH(3)OH)(4)(2)(CH(3)OH)(4) (2), and Co(10)(TC4A)(4)(N(3))(4)(4) (3), have been solvothermally obtained in one pot and structurally characterized by single-crystal X-ray diffraction analyses, powder XRD, and IR spectroscopy. This work presents the first one-dimensional (1) cobalt cluster for the calixarene complexes and another two octanuclear (2) or decanuclear (3) cobalt clusters. In the structures of compounds 1 and 2, a novel N(6)H(2) ligand formed by the in situ (2 + 3) cycloaddition of two azides was observed. Density functional theory (DFT) calculations give the heat of formation (2N(3)(-) + 2H(+) --> N(6)H(2)) and decomposition energy (N(6)H(2) --> 3N(2) + H(2)) of 677.47 and 124.85 kcal/mol, respectively. Furthermore, an intergradation was determined at the B3LYP/6-311++g(d,p) level for the formation of the N(6)H(2) ligand. In addition, one TC4A ligand of a sandwich unit adopts a cone conformation, while the other adopts a pinched cone conformation in 3. The magnetic properties of these three compounds were influenced mainly by the orbital contributions of the distorted octahedral Co(II) ions.