Synthesis and crystal structures of decamethylferrocenium salts of anilate anions derived from bromanilic acid, chloranilic acid and cyananilic acid

Four complexes were synthesized using bis(pentamethylcyclopentadienyl)iron Fe(C5Me5)2 as an organometallic donor and three anilic acids (2,5-dibromo-3,6-dihydroxy-1,4-benzoquinone; BA, 2,5-dichloro-3,6-dihydroxy-1,4-benzoquinone; CA and 2,5-dicyano-3,6-dihydroxy-1,4-benzoquinone; CNA) as an organic acceptor. The molecular-based structures with different stoichiometric ratios [1:1, 1:1:1(H2O) and 2:1] of these complexes have been determined by X-ray crystallographic analysis and elemental analysis. These complexes have a one-dimensional alternated stacking arrangement as ⋯D+A−D+A−⋯ type. Close contacts between the bromine atoms and oxygen atoms of the BA units are observed in the structure [Fe(C5Me5)2](BA) (1) of 1:1 composition. Interestingly, the structures [Fe(C5Me5)2](CA)(H2O) (2) and [Fe(C5Me5)2](CNA)(H2O) (3) of 1:1:1(H2O) ratio contain one-dimensional molecular tape structures with the combination of the CA or the CNA units and water molecules via O–H⋯O hydrogen bonds. Different stoichiometric ratios and structures are found from the CNA complexes [Fe(C5Me5)2](CNA)(H2O) (3) and [Fe(C5Me5)2]2(CNA) (4).