Preparation, structure, and dynamic and electrochemical behaviors of dinuclear rhodium(I) complexes with bridging formamidinato ligands

Yuki Ide, Takahisa Ikeue, Yusuke Kataoka, Ryoko Inoue, Mikio Nakamura, Daisuke Yoshioka, Masahiro Mikuriya, Tatsuya Kawamoto, Makoto Handa

研究成果: Article査読

抄録

Dinuclear rhodium(I) complexes, [Rh(4-Me-pf) (cod)]2 (1), [Rh(3,5-Me2-pf) (cod)]2 (2), [Rh(4-Me-pf) (nbd)]2 (3), [Rh(3,5-Me2-pf) (nbd)]2 (4), and [Rh(2,6-F2-pf) (nbd)]2 (5), have been synthesized and characterized by X-ray structure analysis, 1H, 13C, and 19F NMR, UV-vis, ESI-TOF-MS, and elemental analysis. In these complexes, two rhodium atoms are bridged by two formamidinato ligands and each rhodium atom is coordinated by one chelating cod or nbd ligand to form an approximately square planar coordination structure with two nitrogen atoms and two double bonds. The Rh··Rh distances are in the range of 3.2668 to 2.9726 Å, suggesting a direct bonding interaction between two rhodium atoms. Variable temperature NMR studies in CD2Cl2 solution have revealed that 1-5 exhibit a novel dynamic behavior, that is, an interconversion between two enantiomers. The activation parameters for racemization have been determined by the line shape analyses of the 1H and 19F NMR spectra taken at various temperatures. Variable temperature NMR studies have also revealed that the rotation rates of the four aryl groups around N-C(aryl) bonds are extremely different in each complex. The cyclic voltammetry study has shown that the oxidation potentials corresponding to Rh23+/Rh2+ are 0.41 V in the cod complexes (1 and 2) while those in the nbd complexes (3-5) have shown negative shift by ca. 0.2 V. The reasons for the difference in dynamic behaviors and redox properties among these complexes have been discussed.

本文言語English
ページ(範囲)92-103
ページ数12
ジャーナルJournal of Organometallic Chemistry
803
DOI
出版ステータスPublished - 2016 2 1

ASJC Scopus subject areas

  • 生化学
  • 物理化学および理論化学
  • 有機化学
  • 無機化学
  • 材料化学

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