What is the leading mechanism for the nonradiative decay of the lowest triplet state of aromatic hydrocarbons?

Metz, F.; Friedrich, S.; Hohlneicher, Georg

doi:10.1016/0009-2614(72)80291-4

Cited by 125 publications

(31 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It appears that the triplet parameters D, E, Ax, A r and A z of the corroles are lar less sensitive to metal incorporation than those of the corresponding porphyrins. In planar or nearly planar porphyrins the insertion of relatively small metal ions such as Zn(II) [26,44] or Ga(III) [45] results in a preferential population of the out-of-plane triplet level due to enhanced spin-orbit coupling (SOC) [46]. This is in sharp contrast with the present observations: coordination of Ga(III) [31] or even Sn(IV) does not affect the triplet state populations.…”

Section: Triplet State Of Sn(cl)(tpfc)contrasting

confidence: 57%

Exploring the photoexcited triplet states of aluminum and tin corroles by time-resolved Q-band EPR

et al. 2006

View full text Add to dashboard Cite

The photoexcited triplet states of three 5,10,15-tris(pentafluorophenyl)corroles (tpfc), hosting Sn(IV) and AI(III) in their core, namely, Sn(Cl)(tpfc), Al(pyr)2(tpfc ) and Al(pyr)2(tpfc-Brs), were studied by time-resolved electron paramagnetic resonance (TREPR) spectroscopy in the nematic liquid crystal E7. Only two of these metallocorroles, namely, Sn(C1)(tpfc) and Al(pyr)2(tpfc-Br8), exhibit TREPR spectra following pulsed laser excitation. This result is rationalized in terms of a very low quantum yield of triplet formation in Al(pyr)2(tpfc ). Analysis of the spin polarized Q-band (34 GHz) EPR spectra of Sn(Cl)(tpfc) and Al(pyr)2(tpfc-Brs) provides detailed information on the magnetic and kinetic parameters of the triplet states as well as on the molecular ordering of the complexes in the liquid crystal. With the assignment of the zero-field splitting parameter D < 0 for the Sn(C1)(tpfc) and Al(pyr)2(tpfc-Brs), one can evaluate the dominant intersystem crossing path for these metallocorroles. Analysis reveals that in Sn(C1)(tpfc) the in-plane triplet sublevels are preferentially populated, i.e., A x, A r >> A z. This can be rationalized in terms of weak electronic interactions between the Sn(IV) ion and the corrole n-system, consistent with the domed structure of Sn(Cl)(tpfc). In Al(pyr)2(tpfc-Brs), however, the out-of-plane triplet sublevel is predominantly populated, i.e., A z > A x, Ar, which is attributed to a large increase in the spin-orbit coupling strength arising from the peripheral bromine atoms on the corrole skeleton.

show abstract

Section: Triplet State Of Sn(cl)(tpfc)contrasting

confidence: 57%

Exploring the photoexcited triplet states of aluminum and tin corroles by time-resolved Q-band EPR

et al. 2006

View full text Add to dashboard Cite

show abstract

“…However, the external heavy atom effect is very small for the morphine hydrochloride/CH2Clz sample and negligible for the codeine/CH2C12 sample. A more important conclusion can be drawn form the well known ordering for aromatic molecules (Metz et al. 1972) which is also found for all our alkaloid samples.…”

Section: Ochsupporting

confidence: 67%

The Lowest Excited Triplet States of Codeine and Morphine and of Their Molecular Subunits Veratrole and Guaiacol

Slama

Basché

Bräuchle

et al. 1988

Photochem & Photobiology

View full text Add to dashboard Cite

Abstract— The lowest excited triplet T1 states of the two alkaloids, morphine and codeine, have been investigated by ODMR and emission spectroscopy. The electronic character of their T1 states could be determined by comparing the T1 properties with those of the constituent parts guaiacol and veratrole. The T1 properties, e.g. phosphorescence spectra, zero‐field splitting parameters and triplet sublevel selective decay rates are very similar for the constituent parts and the alkaloids. Thus, in analogy to veratrole and guaiacol, the T1 state of codeine and morphine is assigned to a ππ* state mainly localized on the benzene ring and the attached alkoxy and hydroxy groups. There is no evidence for a contribution from the other subunits, trialkylamine and unsaturated alcohol, to the T1 state of codeine and morphine.

show abstract

“…26 In organic molecules, ISC is typically induced by vibronic spin-orbit interactions rather than direct spinorbit coupling. 24,27 Non-zero spin-orbit coupling matrix elements arise from mixing of the pp* S 1 and T 1 states with close-lying states with sp character induced by molecular vibrations. [27][28][29] Simple symmetry arguments explain the prevalence of ISC to the in-plane triplet sublevels in planar organic molecules.…”

Section: Time-resolved Eprmentioning

confidence: 99%

Photoexcited triplet states of twisted acenes investigated by Electron Paramagnetic Resonance

Tait

Bedi

Gidron

et al. 2019

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

What is the leading mechanism for the nonradiative decay of the lowest triplet state of aromatic hydrocarbons?

Cited by 125 publications

References 15 publications

Exploring the photoexcited triplet states of aluminum and tin corroles by time-resolved Q-band EPR

Exploring the photoexcited triplet states of aluminum and tin corroles by time-resolved Q-band EPR

The Lowest Excited Triplet States of Codeine and Morphine and of Their Molecular Subunits Veratrole and Guaiacol

Photoexcited triplet states of twisted acenes investigated by Electron Paramagnetic Resonance

Contact Info

Product

Resources

About