Supramolecular complexation and photocyclodimerization of methyl 3‑methoxy‑2‑naphthoate with modified &gamma;‑cyclodextrins

Liang, Wenting; Zhang, Hui-Hui; Wang, Jing-Jing; Peng, Yuan; Chen, Bin; Yang, Cheng; Tung, Chen-Ho; Wu, Li-Zhu; Fukuhara, Gaku; Mori, Tadashi; Inoue, Yoshihisa

doi:10.1351/PAC-CON-10-10-04

Pure Appl. Chem., 2011, Vol. 83, No. 4, pp. 769-778

http://dx.doi.org/10.1351/PAC-CON-10-10-04

Published online 2011-02-23

Supramolecular complexation and photocyclodimerization of methyl 3‑methoxy‑2‑naphthoate with modified γ‑cyclodextrins

Wenting Liang¹, Hui-Hui Zhang², Jing-Jing Wang², Yuan Peng³, Bin Chen², Cheng Yang¹*, Chen-Ho Tung², Li-Zhu Wu²*, Gaku Fukuhara¹, Tadashi Mori¹ and Yoshihisa Inoue¹*

¹ PRESTO, JST and Department of Chemistry, Osaka University, Yamada-oka, Suita 565-0871, Japan
² Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry & Graduate University, The Chinese Academy of Sciences, Beijing 100190 China
³ Chengdu Environment Monitoring Center, Chengdu 610071, China

Abstract: A series of modified γ-cyclodextrins (CDs) were prepared as chiral host for catalyzing the enantiodifferentiating photocyclodimerization of methyl 3-methoxy-2-naphthoate (NA). The complexation behavior of NA with modified γ-CDs was studied by UV–vis, fluorescence, and circular dichroism spectroscopies. All of the modified γ-CDs formed stable 1:2 host–guest complex with NA, and binding affinities for two-step complexation critically depended on the structure of modified γ-CDs. The enantioselectivity of NA photocyclodimerization was also significantly affected by the modification of γ-CD. The secondary rim-modification considerably reduced the enantioselectivity, for which the interrupted hydrogen-bonding network, leading to a flexible CD skeleton, is most probably responsible.