The varied structures of cobalt(II)–pyridine (py)–sulfate: [Co(SO4)(py)4]n, [Co2(SO4)2(py)6]n, and [Co3(SO4)3(py)11]n

Abstract

The solid-state structures of two cobalt–pyridine–sulfate compounds, namely catena-poly[[tetrakis(pyridine-κN)cobalt(II)]-μ-sulfato-κ2O:O′], [Co(SO4)(C5H5N)4]n, (1), and catena-poly[[tetrakis(pyridine-κN)cobalt(II)]-μ-sulfato-κ3O:O′,O′′-[bis(pyridine-κN)cobalt(II)]-μ-sulfato-κ3O,O′:O′′]n, [Co2(SO4)2(C5H5N)6]n, (2), are reported. Compound (1) displays a polymeric structure, with infinite chains of CoII cations adopting octahedral N4O2 coordination environments that involve four pyridine ligands and two bridging sulfate ions. Compound (2) is also polymeric with infinite chains of CoII cations. The first Co center has an octahedral N4O2 coordination environment that involves four pyridine ligands and two bridging sulfate ligands. The second Co center has an octahedral N2O4 coordination environment that involves two pyridine ligands and two bridging sulfate ions that chelate the Co atom. The structure of (2) was refined as a two-component inversion twin.

Keywords

• crystal structure
• pyridine
• sulfate
• transition metals
• crystal field theory
• coordination chemistry
• cobalt complexes