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Intramolecular energy transfer between chromophores separated by a rigid steroid bridge: II. Energy transfer as a probe to determine the ratio of two epimers
Author(s) -
Tong ZhenHe,
Yang GuoQiang,
Wu ShiKang
Publication year - 1990
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.19900080109
Subject(s) - chemistry , intramolecular force , chromophore , moiety , acceptor , epimer , steroid , molecule , fluorescence , singlet state , energy transfer , cyclohexane , photochemistry , stereochemistry , excited state , organic chemistry , molecular physics , atomic physics , biochemistry , physics , quantum mechanics , hormone , condensed matter physics
The singlet‐singlet intramolecular energy transfer between naphthalene moiety and dansy! group held apart by a rigid steroid bridge was investigated for two molecules: β‐(1‐naphthyl) acetoxy‐17α‐dansyl‐Δ 5 androstene (3a) and 3β‐(1‐naphthyl)acetoxy‐17 β‐dansyl‐Δ 5 androstene (3b). The rates of energy transfer for 3a and 3b in cyclohexane are 6.9 × 10 6 and 1.1 × 10 8 s −1 respectively. The difference in energy transfer rate between 3a and 3b is attributed to the different donor‐acceptor separation and orientation. The ratio of the two epimers in the synthesized product mixture was obtained from the fluorescence decay measurements.