Cocrystallization of Binuclear Iron(III) Porphyrins with C60: Bending of μ-O{FeIII(Octaethylporphyrin)} and the First Structure of the Iron(III) Octaethyloxophlorin Dimer

Black crystals of C 60 ·μ-O{Fe III (OEP)} 2 ·C 6 H 6 and 2C 60 ·{Fe III (OEPO)} 2 ·4C 6 H 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 6 H 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 ·μ-O{Fe III (OEP)} 2 ·C 6 H 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 (OEPO)} 2 ·4C 6 H 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 porphyrin. 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.