Cocrystallization of Binuclear Iron (III) Porphyrins with C_(60): Bending of μ-O{Fe~(III)(Octaethyloporphyrin)} and the First Structure of the Iron (III) Octaethyloxophylorin Dimer

摘要

Black crystals of C_(60)·μ-O{Fe~(III)(OEP)}_2·C_6H_6 and 2C_(60)·{Fe~(III)(OEPO)}_2·4C_6H_6 suitable for single-crystal X-ray diffraction studies have been obtained by growth from benzene solutions of the appropriate binuclear metalloporphyrin and the fullerene. c_(60)·μ-O{Fe~(III)(OEP)}_2·C_6H_6 crystallizes with two molecules of μ-O{Fe~(III)(OEP)}_2, two fully ordered molecules of C_(60), and two molecules of benzene in the asymmetric unit. Each independent molecule of μ-O{Fe~(III)(OEP)}_2 makes close contact with two fullerene molecules. In C_(60)·μO{Fe~(III)(OEP)}_2·C_6H_6 the Fe-O-Fe angles (150.18(11)° and 151.89(11)°) are markedly bent with a benzene molecule wedged into the opening between the two porphyrins, whereas in the triclinic and monoclinic polymorphs of μ-O{Fe~(III)(OEP)}_2 the Fe-O-Fe angles are more nearly linear (172.16(17)°and 176.2(2)°, respectively). The structure of 2C_(60)·{Fe~(III)(OEP)}_2·4C_6H_6 consists of a centrosymmetric {Fe~(III)(OEPO)}_2 molecule in which the two macrocycles are connected to one another through axial coordination of the meso-oxygen atoms to iron ions in the neighboring prophyrin. Each molecule of {Fe(III)(OEPO)}_2 engages a fullerene on its two exposed faces. The basic geometry of the central core of {Fe~(III)(OEPO)}_2 is similar to that of the previously characterized {In~(III)(OEPO)}_2, but the distortion of the two macrocycles is greater in the former due to the shorter Fe-N and Fe-O bonds.