(η5-Carb-oxy-cyclo-penta-dien-yl)(η7-cyclo-hepta-trien-yl)manganese(I) hexa-fluorido-phosphate

Abstract

The title compound, [Mn(C₇H₇)(C₆H₅O₂)]PF₆ or [(Cht)Mn(Cp'CO₂H)]PF₆, with Cht = cyclo-hepta-trienyl and Cp' = C₅H₄, is an air-stable, purple, heteroleptic, cationic sandwich complex with manganese in oxidation state +I and π-coordinating cyclo-hepta-trienyl and cyclo-penta-dienyl ligands. The latter ligand carries the carb-oxy-lic acid functionality. This 'tromancenium-8-carb-oxy-lic acid' with hexa-fluorido-phosphate as counter-ion represents a rare case of a cationic carb-oxy-lic acid. Structurally, this organometallic carb-oxy-lic acid displays the common motif of planar Osp ²⋯H-Osp ³/Osp ³-H⋯Osp ² hydrogen-bonded carb-oxy-lic acid dimers with anti-oriented metallocenyl moieties, the cationic charge of which is balanced by octa-hedrally shaped hexa-fluorido-phosphate anions. Positional disorder is observed in the cyclo-hepta-trienyl ring and the PF₆ ^- anion.

Keywords: carb­oxy­lic acid; cationic carb­oxy­lic acid; crystal structure; heteroleptic sandwich complexes; manganese; sandwich complexes; tromancenium.