A novel one-dimensional coordination polymer bearing tetrakis-carboxylato Co(II)2 units interacting via P-donors based on 1-carboxylic-1′-(diphenylphosphino)ferrocene

The reaction of Fe(η5-C5H4CO2Na)(η5-C5H4PPh2) (1), obtained upon addition of NaOH to Fe(η5-C5H4CO2H)(η5-C5H4PPh2), with stoichiometric amounts of [Co(H2O)6](NO3)2 (2) gave the 1D coordination polymer [Co(Fe(η5-C5H4CO2)(η5-C5H4PPh2))2]n (3). The molecular structure of 3 in the solid state was determined by single crystal X-ray structure determination. A unique feature of 3 is that dinuclear Co2(O2CR)4 units (R = Fe(η5-C5H4)(η5-C5H4PPh2)) are connected by two diphenylphosphino-ferrocenyl moieties giving rise to a one-dimensional arrangement, whereby the other two Ph2P-containing ferrocenes remain uncoordinated. Due to this structural feature, the coordination sphere at cobalt(II) can best be ascribed as distorted octahedral. Variable temperature dependent magnetic measurements were carried out indicating an overall weak anti-ferromagnetic behaviour with the formation of a weak σ bond with a distance of 2.800(2) Å between the two cobalt(II) ions.

Graphical abstractThe synthesis, structure and magnetic properties of the 1-dimensional coordination polymer [Co(Fe(η5-C5H4CO2)(η5-C5H4PPh2))2]n in the solid state containing Co2(O2CR)4 (R = Fe(η5-C5H4)(η5-C5H4PPh2)) units is reported.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► A novel 1D coordination polymer bearing tetrakis-carboxylato Co(II)2 units has been obtained. ► Magnetic studies reveals a diamagnetic ground state, presumably by weak Co(II)⋯Co(II) interactions. ► A comparison with related complexes reveals opposing tendencies, a phenomena deserving further investigation.