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On the Stereochemistry of Energy Transfer — the Dual Phosphorescence of 1‐Indanones
Author(s) -
Schaffner Kurt,
Amrein Walter,
Larsson IngaMai
Publication year - 1975
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.197500044
Subject(s) - chemistry , intersystem crossing , phosphorescence , intramolecular force , acceptor , naphthalene , photochemistry , bicyclic molecule , internal conversion , stereochemistry , fluorescence , singlet state , atomic physics , excited state , organic chemistry , physics , quantum mechanics , astronomy , condensed matter physics , spectral line
The results of a stereochemical study of the intramolecular triplet energy transfer between indanone (donor) and naphthalene (acceptor) groups are discussed. Two diastereoisomeric spatial arrangements were chosen in which the donor occupies the endo and exo configuration, respectively, on conformationally rigid bicyclic frames 1,8‐ and 2,3‐annelated to naphthalene. In the endo geometry a transfer route via a triplet donor‐acceptor exciplex specific to through‐space interaction between the two π systems (providing for additional radiationless T → S deactivation) is proposed to compete with an efficient through‐α‐bond exchange transfer mechanism operative in both the endo and exo arrangements. In connection with this study the dual phosphorescence phenomenon of 1‐indanone was reinvestigated. It was found that the favored intersystem crossing routes are S 1 ( n , π*) → T( n , π*) and S 2,3 (π,π*n) → T(π,π*) and that internal conversion to S 1 competes efficiently with S(π,π*) → T(π,π*) intersystem crossing only from higher vibrational levels of the S 2 and S 3 states.