Photooxidation of Hantzsch 1,4-dihydropyridines (1,4-DHP,1a-1d) by direct irradiation (λ > 300 nm) under an oxygen atmosphere has been carefully examined in this work. Spectroscopic and electrochemical studies demonstrate that photoinduced singlet electron transfer from 1,4-DHP to molecular oxygen occurs. The generated superoxide radical anion (O2-·) is responsible for this typical photochemical oxidation.
A chiral complex of (R,R)-Pd was prepared by reaction of optically pure (R,R)-bis(pyrrol-2-ylmethyl-eneamino) cyclohexane ligand with Pd(OAc)2·2H2O under the base condition at room temperature. The weak intermolecular C-H···Pd interaction was found to be responsible for the homochiral M helix for-mation of the neutral,chiral,mononuclear (R,R)-Pd in the crystal packing.
