Abstract
Formations of chiral photopyridones(2) from 2-pyridones(1) are very interesting as examples of photoreaction theory, chiral syntheses and solar energy-storage. We here report chiral 2 preparation from 1 with chiral hosts((l)-3 etc.), and molecular orbital analyses of the energy and stereochemical changes.The synthesized chiral imido-amido host (l)-3 etc. produced complexes 1a·(l)-3 etc., to follow the photoreactions to give (R)-2a.Molecular simulation of the excited singlet state (S1) 1* showed that 1* exists as two conformers (1*Φ(+) and 1*Φ(-): ΔEK=8∼9kcal/mol) to be non-planer and enantiomeric, and 1*Φ(+) was shown to go to (R)-2a via three kinds of potential energy surfaces(PES).Formation of (R)-2a by photoreaction of the 1a·(l)-3 complex was simulated to be introduced to 1*Φ(+)·(l)-3 by S1 excitation of the 1a·(l)-3, followed by decrease of the r3-6 and deactivation to (R)-2a. We then verified that molecular simulation of similar 1a·(d)-3 singlet excitation gives (S)-2a, and that molecular simulation of 1a·6 host-guest experiments by Bachs´ also gives (R)-2a.Moreover we checked the large energy-storage, substituent effect, and acid-catalyst effects for 1⇔2 recycle reactions, and propose new solar energy-storage and photosensitized systems.
