title: Peculiarities of C60*- coordination to cobalt(II) octaethylporphyrin in ionic multicomponent complexes: Observation of the reversible formation of Co-C(C60-) coordination bonds.
abstract: Ionic multicomponent complexes containing the C60- anion, cobalt(II) octaethylporphyrin (OEP), and the noncoordinating tetramethylphosphonium cation (TMP+), [(TMP+){Co(II)OEP(C60-)}(C6H5CN)x(C6H4Cl2)(1-x)] (x congruent with 0.75) (1), or the coordinating cation of N-methyldiazabicyclooctane (MDABCO+), [{(MDABCO+)Co(II)OEP(C60-)}(C6H5CN)x(C6H4Cl2)(1-x)] (x congruent with 0.67) (2), were obtained. Diamagnetic sigma-bonded {Co(II)OEP(C60-)} units in 1 have the Co...C(C60-) distance of 2.268(1) A at 100 K and are stable up to 290 K. Both MDABCO+ and C60- coordinate to Co(II)OEP in 2. In this case, a noticeably longer Co...CC60-) distance of 2.508(4) A was observed at 100 K. As a result, the unprecedented reversible formation of the Co-C(C60-) coordination sigma bond is realized in 2 and is accompanied by a transition from a paramagnetic to a diamagnetic state in the 50-250 K range. It was shown, for the first time, that the Co...C distance of about 2.51 A is a boundary distance below which the Co-C(C60-) coordination bond is formed.
authors: Division of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan. konarev@icp.ac.ru
authors: Dmitri V
authors: DV
authors: Konarev
authors: Salavat S
authors: SS
authors: Khasanov
authors: Akihiro
authors: A
authors: Otsuka
authors: Gunzi
authors: G
authors: Saito
authors: Rimma N
authors: RN
authors: Lyubovskaya