Investigating the solid state hosting abilities of homo- and hetero-valent [Co-7] metallocalix[6]arenes

Abstract

A family of homo-valent [Co(II)(7)(OH)(6)(L-1)(6)](NO3)(2)(1), [(MeOH)(2)subset of Co(II)(7)(OH)(6)(L-1)(6)](NO3)(2) (2) (where L1H = 2-iminomethyl-6-methoxyphenol) and hetero-valent [(NO3)(2)subset of Co(III)Co(II)(6)(OH)(6)(L-2)(6)]-(NO3)center dot 3MeCN (4) (where L2H = 2-iminophenyl-6-methoxyphenol) complexes possess metallic skeletons describing planar hexagonal discs. Their organic exteriors form double-bowl shaped topologies, and coupled with their 3-D connectivity, this results in the formation of molecular cavities in the solid state. These confined spaces are shown to behave as host units in the solid state for guests including solvent molecules and charge balancing counter anions. Magnetic susceptibility measurements on 2 and 4 reveal weak ferro-and ferrimagnetism, respectively. The utilisation of other Co(II) salt precursors gives rise to entirely different species including the mononuclear and trinuclear complexes [Co(II)(L-2)(2)] (5) and [Co(III)(2)Na(I)(1)(L-3)(6)](BF4) (6) (where L3H = 2-iminomethyl-4-bromo-6-methoxyphenol).