| Summary: | A novel heteroleptic paddlewheel-type dirhodium (Rh<sub>2</sub>) complex [Rh<sub>2</sub>(O<sub>2</sub>CCH<sub>3</sub>)<sub>3</sub>(PABC)] (<b>1</b>; PABC = <i>para</i>-aminobenzenecarboxylate), which has an amino group as a potential donor site for coordination with the metal ion, was synthesized and characterized by <sup>1</sup>H NMR, ESI-TOF-MS, infrared spectra, and elemental analysis. The slow evaporation of <i>N,N</i>-dimethylformamide (DMF)-dissolved <b>1</b> produces the purple-colored crystalline polymeric species [Rh<sub>2</sub>(O<sub>2</sub>CCH<sub>3</sub>)<sub>3</sub> (PABC)(DMF)]<sub>n</sub> (<b>1P</b>). Single-crystal and powder X-ray diffraction analyses, as well as thermo-gravimetric analysis, clarified that <b>1P</b> formed a one-dimensional polymeric structure, in which the two axial sites of the Rh<sub>2</sub> ion in <b>1P</b> are coordinated by a DMF molecule and an amino group of the PABC ligand of the neighboring molecule <b>1</b>, by coordination-induced self-assembly (polymerization) with an Rh-amino bond. The reversible structural change (self-assembly and disassembly transformations) between the discrete species [Rh<sub>2</sub>(O<sub>2</sub>CCH<sub>3</sub>)<sub>3</sub>(PABC)(DMF)<sub>2</sub>] (<b>1D</b>; green solution) and the polymeric species <b>1P</b> (purple solid) was accompanied by a color change, which easily occurred by the dissolution and evaporation procedures with DMF.
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