Extending the scope of the carbonyl facilitated triplet excited state towards visible light excitation

2018 ◽  
Vol 20 (28) ◽  
pp. 19120-19128 ◽  
Author(s):  
Shinaj K. Rajagopal ◽  
Nagaraj K. ◽  
Somadrita Deb ◽  
Vinayak Bhat ◽  
Devika Sasikumar ◽  
...  

A series of extended π-conjugated benzophenone analogs was synthesized through a facile Lewis-acid catalyzed Friedel–Crafts reaction in order to exploit the integral triplet state properties of benzophenone.

2014 ◽  
Vol 50 (98) ◽  
pp. 15627-15630 ◽  
Author(s):  
Fen Wang ◽  
Xiaoneng Cui ◽  
Zhangrong Lou ◽  
Jianzhang Zhao ◽  
Ming Bao ◽  
...  

Rhodamine was used as an acid-responsive moiety for switching of the triplet state production and visible light absorption of rhodamine-C60 dyads.


Author(s):  
Sergey A. Bagnich ◽  
Alexander Rudnick ◽  
Pamela Schroegel ◽  
Peter Strohriegl ◽  
Anna Köhler

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.


1970 ◽  
Vol 48 (4) ◽  
pp. 694-696 ◽  
Author(s):  
A. G. Szabo ◽  
W. D. Rlddell ◽  
R. W. Yip

The transient produced on flash excitation of degassed solutions of thymine in acetonitrile has been characterized as the triplet excited state of thymine. This triplet state has a lifetime of 14 ± 1 μs and the associated dimerization rate was found to be 5.3 ± 0.3 × 108 M−1 s−1. The triplet state of thymine could be quenched by 2,4-hexadien-1-ol with a rate constant of 8.1 ± 0.6 × 109 M−1 s−1.


2016 ◽  
Vol 15 (11) ◽  
pp. 1358-1365 ◽  
Author(s):  
Zafar Mahmood ◽  
Jianzhang Zhao

Different from the singlet excited state (fluorescence), the triplet state of the probes is not quenched by photo-induced electron transfer.


2018 ◽  
Vol 17 (7) ◽  
pp. 896-902 ◽  
Author(s):  
Grigory Smolentsev ◽  
Kaj M. van Vliet ◽  
Nicolo Azzaroli ◽  
Jeroen A. van Bokhoven ◽  
Albert M. Brouwer ◽  
...  

The triplet excited state of a new Ir-based photosensitizer with two chromenopyridinone and one bipyridine-based ligands has been studied by pump–probe X-ray absorption spectroscopy (XANES) coupled with DFT calculations.


2018 ◽  
Vol 20 (12) ◽  
pp. 8016-8031 ◽  
Author(s):  
Mikhail A. Filatov ◽  
Safakath Karuthedath ◽  
Pavel M. Polestshuk ◽  
Susan Callaghan ◽  
Keith J. Flanagan ◽  
...  

Heavy atom-free BODIPY–anthracene dyads show triplet excited state formation via PeT, controlled by molecular rotation and environmental polarity.


2005 ◽  
Vol 09 (05) ◽  
pp. 316-325 ◽  
Author(s):  
Itumeleng Seotsanyana-Mokhosi ◽  
Ji-Yao Chen ◽  
Tebello Nyokong

Adjacent binaphthalo-phthalocyanines tetra-substituted with phenoxy (4a), 4-carboxyphenoxy (4b) and 4-t-butylphenoxy (4c) groups, as well as the di-substituted 4-carboxyphenoxy (5b) have been synthesized and characterized. The photophysical and photochemical behavior of 4a-c, were compared with those of the corresponding di-substituted derivatives, (5a-c). The secondary substituents on the phenoxy ring have an influence on the aggregation of the molecules and hence on their photophysical properties. All of the complexes exhibit a relatively good conversion of energy from the triplet-excited state to the singlet oxygen. The less aggregated molecule (4c), has the highest singlet oxygen quantum yield. For all the molecules, fluorescence yields are low and they all have relatively shorter triplet lifetimes compared with the unsubstituted zinc phthalocyanine. Increasing the number of ring substituents on these rigid MPc complexes (from complexes 5 to 4) showed a general increase in the triplet state lifetimes and singlet oxygen quantum yields, and a decrease in stability.


2018 ◽  
Vol 20 (25) ◽  
pp. 17504-17516 ◽  
Author(s):  
Huimin Guo ◽  
Lijuan Zhu ◽  
Can Dang ◽  
Jianzhang Zhao ◽  
Bernhard Dick

Phosphorescent emission from a flavin localized triplet excited state (3IL) is observed for the first time in a flavin decorated tris(dipyridine) Ru(ii) complex with strong visible light absorption.


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