Tris[bis(1-methyl-1H-imidazol-2-yl)methanone-kappa N-2(3)]iron(II) dichloride 5.5-hydrate, cis-bis[bis(1-methyl-1H-imidazol-2-yl)methanone-kappa N-2(3)]dichloroiron(II) (ca 153 K) and di-mu-chloro-bis{[bis(1-methyl-1H-imidazol-2-yl)methanone-kappa N-2(3)]chloroiron(II)} methanol disolvate (ca 300 K)

The first of the title compounds, [Fe(C 9H 10N 4O) 3]Cl 2·5.5H 2O, is the first structurally characterized homoleptic tris[bis(imidazol-2-yl) ketonej-metal complex to be structurally defined. In the second of the title compounds, [FeCl 2(C 9H 10N 4O) 2], a pair of monodentate donors supplants one of the bidentate ligands. In the third complex, [Fe 2Cl 4(C 9H 10N 4O) 2]·2CH 3OH, a centrosymmetric binuclear compound with a pair of bridging chloride ligands, the introduction of a third chloro ligand results in five-coordination about each of the metal atoms; the environments of the latter are square pyramidal, with a chloro ligand at the apex and the two bidentate arrays about the base of the pyramid.