(η(5)-Carb­oxy­cyclo­penta­dien­yl)(η(7)-cyclo­hepta­trien­yl)manganese(I) hexa­fluorido­phosphate

The title compound, [Mn(C(7)H(7))(C(6)H(5)O(2))]PF(6) or [(Cht)Mn(Cp’CO(2)H)]PF(6), with Cht = cyclo­hepta­trienyl and Cp’ = C(5)H(4), is an air-stable, purple, heteroleptic, cationic sandwich complex with manganese in oxidation state +I and π-coordinating cyclo­hepta­trienyl and cyclo­penta­dienyl ligands. The latter ligand carries the carb­oxy­lic acid functionality. This ‘tromancenium-8-carb­oxy­lic acid’ with hexa­fluorido­phosphate as counter-ion represents a rare case of a cationic carb­oxy­lic acid. Structurally, this organometallic carb­oxy­lic acid displays the common motif of planar Osp (2)⋯H—Osp (3)/Osp (3)—H⋯Osp (2) hydrogen-bonded carb­oxy­lic acid dimers with anti-oriented metallocenyl moieties, the cationic charge of which is balanced by octa­hedrally shaped hexa­fluorido­phosphate anions. Positional disorder is observed in the cyclo­hepta­trienyl ring and the PF(6) (−) anion. [Image: see text]