Ferrocenecarboxylic anhydride: identification of a new polymorph

Mehdi Tazi (1) , Thierry Roisnel (1) , Florence Mongin (1) , William Erb (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

A new monoclinic polymorph of ferrocenecarboxylic anhydride, [Fe(CH)(CHO)], was obtained. Three molecules are present in the asymmetric unit, two of them being nearly identical (r.m.s. deviation = 0.11 Å), with the Fe atoms on the same side of the anhydride functional group. In the third molecule, the two Fe atoms are located at opposite sides of the functional group (ferrocene-ferrocene pseudo-torsion angle = 146.2°), a very unsual feature in metallocene anhydrides. A network of weak intermolecular hydrogen bonds was also disclosed.

Keywords: Hydrogen bonds; metallocene anhydride; polymorph; acid anhydride; Crystal structure; ferrocene

Domains: Chemical Sciences; Coordination chemistry; Chemical Sciences; Cristallography

Mehdi Tazi, Thierry Roisnel, Florence Mongin, William Erb. Ferrocenecarboxylic anhydride: identification of a new polymorph. Acta Crystallographica Section C : Structural Chemistry [2014-..], 2017, 73 (10), pp.760-766. ⟨10.1107/S205322961701124X⟩. ⟨hal-01617956⟩