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.

Ava M Park,James A Golen,Duyen N K Pham,David R Manke

doi:10.1107/s205698901901538x

Abstract

The solid-state structures of two cobalt-pyridine-sulfate compounds, namely catena-poly[[tetra-kis-(pyridine-κN)cobalt(II)]-μ-sulfato-κ2 O:O'], [Co(SO4)(C5H5N)4] n , (1), and catena-poly[[tetra-kis-(pyridine-κN)cobalt(II)]-μ-sulfato-κ3 O:O',O''-[bis-(pyridine-κN)cobalt(II)]-μ-sulfato-κ3 O,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 octa-hedral 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 octa-hedral N4O2 coordination environment that involves four pyridine ligands and two bridging sulfate ligands. The second Co center has an octa-hedral 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.

Highlights

The solid-state structures of two cobalt–pyridine–sulfate compounds, namely catena-poly[[tetrakis(pyridine-N)cobalt(II)]--sulfato-2O:O0], [Co(SO4)(C5H5N)4]n, (1), and catena-poly[[tetrakis(pyridine-N)cobalt(II)]--sulfato3O:O0,O00-[bis(pyridine-N)cobalt(II)]--sulfato-3O,O0:O00]n, [Co2(SO4)2(C5H5N)6]n, (2), are reported
Before we began a crystallographic examination of metal–pyridine–sulfates in 2018, there were only two examples of such complexes without other ligands or components reported in the literature (Cotton & Reid, 1984; Memon et al, 2006)
The coordination environment of each compound can usually be predicted with crystal field theory, the exact nature is dependent upon the number of pyridines bound and the binding mode of the sulfate anion

Summary

Chemical context

The synthesis of metal–pyrdine–sulfates has been reported since the 19th century, when Jørgensen’s chain theory was still the prevailing hypothesis (Reitzenstein, 1894; Howe, 1898). Despite the long history of these compounds, their crystallographic study is rather limited. Before we began a crystallographic examination of metal–pyridine–sulfates in 2018, there were only two examples of such complexes without other ligands or components reported in the literature (Cotton & Reid, 1984; Memon et al, 2006). Since we began studying the structural chemistry of metal– pyridine–sulfates, we have observed many different structural motifs in the complexes. The coordination environment of each compound can usually be predicted with crystal field theory, the exact nature is dependent upon the number of pyridines bound and the binding mode of the sulfate anion. The sulfate anion can have a number of different coordination modes, including -sulfato-2-O:O, -sulfato-2-O:O0 and -sulfato-3-O:O0:O". Symmetry codes: (i) Àx þ 1; Ày þ 1; Àz þ 1; (ii) Àx þ 1; y; Àz þ 32

Structural commentary

Supramolecular features

Database survey

Synthesis and crystallization

Refinement