A photochromic diarylethene, 1,2-bis(2-methyl-5-(4-N,N-dimethylaminophenyl)thien-3-yl)perfluorocyclopentene in proton-donating media was studied. The ammonium salt came into being in the presence of acetic acid following localization of lone pair electrons of the amino group. The maximum absorption of the salt had a 36 nm hypsochromic shift, and its molar extinction coefficient increased to 3.494×10 4 L•mol -1 •cm -1 . The conjugational and delocalizational energy levels were calculated by Gaussian 98, and its hypsochromic shift mechanism was also discussed.

Polyphenylalkyne derivatives Q 0750Synthesis of New C2-Symmetric Bis(β-hydroxy amide) Ligands and Their Applications in the Enantioselective Addition of Alkynylzinc to Aldehydes. -A number of title ligands such as (I) is prepared. Among them, the derivative (Ia) provides the best results. -(HUI*, X.-P.; YIN, C.; CHEN