K. Oguni et al., C-13 NMR-STUDY ON DIASTEREOMERIC INTERACTIONS BETWEEN CELLULOSE TRIS(4-METHYLBENZOATE) AND 1-PHENYLETHANOL ENANTIOMERS, Polymer Journal, 26(11), 1994, pp. 1257-1261
For investigating the mechanism of chiral recognition by cellulose der
ivatives, C-13 NMR spectra of 1-phenylethanol were measured in CDCl3 i
n the presence or absence of cellulose tris(4-methylbenzoate) (1). (R)
- and (S)-enantiomers of 1-phenylethanol showed different chemical shi
fts in the presence of 1. The degree of chemical shift difference was
large at aromatic ipso carbon (1'-C) and methine carbon (1-C) with a h
ydroxyl group. Spin-lattice relaxation times (T1s) were also measured
to compare mobilities of the enantiomers. In the presence of 1, T1 for
each carbon of the (R)-enantiomer was shorter than that for correspon
ding carbon of the (S)-enantiomer. The presence of 1 restricts the mob
ility of the (R)-enantiomer more than that of the (S)-enantiomer. T1 d
ifference between (R)- and (S)-enantiomers was large at 1-C. The resul
ts indicate that 1-phenylethanol is chirally recognized by 1 at the po
int of 1-C carbon.