Phthalocyanines with two and four optically active binaphthyl units have been synthesized and characterized by electronic absorption, CD, and MCD spectroscopy. The chiral substituents induce CD in the in-plane polarized Q and Soret bands of phthalocyanines: phthalocyanines having R and S binaphthyls show positive and negative CD, respectively. The geometries of the compounds were optimized at the PM3 level, and a vector coupling model for the induction of rotatory strength was developed. This model provides a semi-quantitative description of the CD spectra. Thus, not only the sign of the CD spectra but also the intensity relationship between the Soret and Q CD bands and, further, the shape of the Q CD band were reasonably explained. The discussion focuses on the important role of the central hydrogen atoms.
ASJC Scopus subject areas
- Colloid and Surface Chemistry