E.P.R. studies of the lowest excited triplet states of aromatic carbonyl molecules in mixed organic crystals
- 1 February 1974
- journal article
- research article
- Published by Taylor & Francis in Molecular Physics
- Vol. 27 (2) , 309-326
- https://doi.org/10.1080/00268977400100301
Abstract
Detailed single-crystal E.P.R. studies of the lowest excited triplet states (T 1) of a series of aromatic carbonyl molecules, such as acetophenone, substituted acetophenones and substituted benzaldehydes, were made using 1,4-dibromobenzene and durene as hosts. Signs and magnitudes of the zero field splittings (ZFS), directions of the principal axes of the ZF tensor, and the orientations of the guest molecules with respect to the host molecules were determined for a series of aromatic carbonyl molecules. The results obtained are consistent with the 3ππ* assignment of the T 1 states of the systems studied here. Comparisons of the observed ZFS and those estimated from the Hayashi-Nagakura analysis were made for several systems. Hyperfine interactions and spin distributions were investigated in the case of 4-fluoroacetophenone. The large spin density at the 4 position (ρ4 = 0·28) was discussed in terms of the 3ππ* assignment and compared with those of the related triplet state molecules and radical anions.Keywords
This publication has 17 references indexed in Scilit:
- PMDR studies of the magnetic and dynamic properties of the lowest excited triplet states of aromatic carbonyl molecules : acetophenone, benzaldehyde and their derivativesMolecular Physics, 1974
- Studies of electronic structures of the lowest excited triplet states of substituted benzenes and pyridines by EPRChemical Physics Letters, 1972
- Single crystal EPR studies of photoexcited triplet states of aromatic carbonyl molecules and substituted benzenes; enhancement of the EPR signals by energy transferChemical Physics Letters, 1972
- Optically detected ESR studies of the lowest triplet state of 1-indanone and α-tetraloneChemical Physics Letters, 1972
- EPR studies of n-π* triplet states and the comparison of the n-π* triplet states of aromatic carbonyl compoundsChemical Physics Letters, 1969
- Lowest π, π* Triplet State of AcetophenoneThe Journal of Chemical Physics, 1967
- Singlet—Triplet Transitions in p-Dihalogenated BenzenesThe Journal of Chemical Physics, 1967
- Paramagnetic Resonance Absorption in Naphthalene in Its Phosphorescent StateThe Journal of Chemical Physics, 1961
- The crystal and molecular structure of 1:4-dimethoxybenzeneActa Crystallographica, 1950
- X-ray analysis of the crystal structure of dureneProceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 1933