The Effect of Substitution of 3-Perylenyl Group, an Aromatic Nucleus with a Very Low Triplet Energy, on Photochemical Isomerization of the Unsaturated Bond. Direct Observation of Triplet State Isomerization of a Styrene Derivative

1994 ◽  
Vol 23 (2) ◽  
pp. 205-208 ◽  
Author(s):  
Tatsuo Arai ◽  
Osamu Takahashi ◽  
Tomoyuki Asano ◽  
Katsumi Tokumaru
Keyword(s):  
Triplet State ◽  
Direct Observation ◽  
Aromatic Nucleus ◽  
Triplet Energy ◽  
Unsaturated Bond ◽  
Photochemical Isomerization

scholarly journals Triplet energies and excimer formation in meta - and para -linked carbazolebiphenyl matrix materials

2015 ◽  
Vol 373 (2044) ◽  
pp. 20140446 ◽  
Author(s):  
Sergey A. Bagnich ◽  
Alexander Rudnick ◽  
Pamela Schroegel ◽  
Peter Strohriegl ◽  
Anna Köhler
Keyword(s):  
Excited State ◽  
Triplet State ◽  
Spectroscopic Investigation ◽  
Triplet Excited State ◽  
Conjugation Length ◽  
Triplet Energy ◽  
Excimer Formation

We present a spectroscopic investigation on the effect of changing the position where carbazole is attached to biphenyl in carbazolebiphenyl (CBP) on the triplet state energies and the propensity to excimer formation. For this, two CBP derivatives have been prepared with the carbazole moieties attached at the ( para ) 4- and 4 ′ -positions ( p CBP) and at the ( meta ) 3- and 3 ′ -positions ( m CBP) of the biphenyls. These compounds are compared to analogous m CDBP and p CDBP, i.e. two highly twisted carbazoledimethylbiphenyls, which have a high triplet energy at about 3.0 eV and tend to form triplet excimers in a neat film. This torsion in the structure is associated with localization of the excited state onto the carbazole moieties. We find that in m CBP and p CBP, excimer formation is prevented by localization of the triplet excited state onto the central moiety. As conjugation can continue from the central biphenyls into the nitrogen of the carbazole in the para -connected p CBP, emission involves mainly the benzidine. By contrast, the meta -linkage in m CBP limits conjugation to the central biphenyl. The associated shorter conjugation length is the reason for the higher triplet energy of 2.8 eV in m CBP compared with the 2.65 eV in p CBP.

scholarly journals Electron Nuclear Double Resonance of the Chlorophyll Triplet State in the Water-Soluble Chlorophyll Protein from Brassica oleracea: Investigation of the Effect of the Binding Site on the Hyperfine Couplings

2020 ◽  
Vol 51 (9-10) ◽  
pp. 925-937
Author(s):  
Alessandro Agostini ◽  
Daniel M. Palm ◽  
Harald Paulsen ◽  
Marilena Di Valentin ◽  
Donatella Carbonera
Keyword(s):  
Triplet State ◽  
Brassica Oleracea ◽  
Double Resonance ◽  
Water Soluble ◽  
Triplet States ◽  
Triplet Energy ◽  
Electron Nuclear Double Resonance ◽  
Light Harvesting Complexes ◽  
Chlorophyll Protein ◽  
Hyperfine Couplings

Abstract An investigation of the photoexcited triplet state of chlorophyll (Chl) a in the water-soluble chlorophyll protein (WSCP) of Brassica oleracea has been carried out by means of electron-nuclear double resonance (ENDOR), achieving a complete assignment of the observed hyperfine couplings corresponding to methine protons and methyl groups of Chl a triplet state. The triplet-state properties, and in particular the hyperfine couplings, were found to be similar to those previously reported for Chl a in the WSCP of Lepidium virginicum. Therefore, the porphyrin ring deformation observed in Brassica oleracea WSCP seems to only slightly affect the spin density of 3Chl a. This may be relevant when considering the robustness of triplet–triplet energy transfer mechanisms, relying on wavefunction overlap, in systems, such as the photosynthetic light-harvesting complexes, in which Chl triplet states with distorted geometries are involved.

scholarly journals Accurate calculations of geometries and singlet–triplet energy differences for active-site models of [NiFe] hydrogenase

2014 ◽  
Vol 16 (17) ◽  
pp. 7927-7938 ◽  
Author(s):  
Mickaël G. Delcey ◽  
Kristine Pierloot ◽  
Quan M. Phung ◽  
Steven Vancoillie ◽  
Roland Lindh ◽  
...  
Keyword(s):  
Triplet State ◽  
Active Site ◽  
Relative Stability ◽  
Quantum Mechanical ◽  
Triplet Energy ◽  
Mechanical Methods ◽  
State Models

The relative stability of singlet and triplet state models of [NiFe] hydrogenase have been studied by advanced quantum-mechanical methods.

1,4-Azaborine as a controller of triplet energy, exciton distribution, and aromaticity in [6]cycloparaphenylenes

2017 ◽  
Vol 5 (35) ◽  
pp. 9088-9097 ◽  
Author(s):  
Jie Wu ◽  
Yuhe Kan ◽  
Zhenhua Xue ◽  
Jintian Huang ◽  
Peng Chen ◽  
...  
Keyword(s):  
Triplet State ◽  
Triplet Energy ◽  
Control Distribution ◽  
Triplet Excitons ◽  
Exciton Distribution

Introduction of 1,4-azaborine rings at different positions of the [6]CPP hoop can efficiently control distribution of triplet excitons, triplet-state aromaticity, and triplet energy in [6]CPP.

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