Completing the bis­[hy­droxy­bis(pyridin-2-yl)methane­sulfonato-κ³N,O,N′]M^II series (M = Mn to Zn) with the copper(II) and cobalt(II) structures

The Cu^II complex bis­[hy­droxy­bis­(pyridin-2-yl)methane­sul­fon­ato-κ³N,O,N′]copper(II) hexa­hydrate, [Cu(C₁₁H₉N₂O₄S)₂]·6H₂O, (I), crystallizes in the space group P, compared with P2₁/c for the anhydrous Co^II analogue bis­[hy­droxy­bis­(pyridin-2-yl)methane­sulfonato-κ³N,O,N′]cobalt(II), [Co(C₁₁H₉N₂O₄S)₂], (II). However, both mol­ecules sit on a crystallographic inversion centre and are thus very similar in appearance. Jahn–Teller elongation of the Cu—O bonds [2.347 (3) Å in (I) and 2.064 (2) Å in (II)] influences the S—O bond lengths, which are all around 1.455 (3) Å in (I) and 1.436 (2)–1.473 (2) Å in (II).