Paddlewheel Complexes with Azulenes: Electronic Interaction between Metal Centers and Equatorial Ligands.

Rhodium dinuclear complexes (1-3) with azulene moieties as equatorial ligands were obtained by reacting Rh (OAc) with guaiazulene-2-carboxylic acid, azulene-2-carboxylic acid, and azulene-1-carboxylic acid, respectively. The molecular structures in their crystalline states were determined by X-ray diffraction to be 1 ⋅ (H O) , 1 ⋅ (MeCN) , 2 ⋅ (MeCN) , and 3 ⋅ (DMF) , which were coordinated with the crystallization solvent at the axial positions. Among these, the crystal packing of 1 ⋅ (H O) , 1 ⋅ (MeCN) , and 3 ⋅ (DMF) revealed the formation of one-dimensional stacked chains nearly along the axial direction and of two-dimensional stacked sheets along the equatorial direction.