scholarly journals No Electron-Donating Substituent Effect on the Singlet Excited State Formation from the 5-(5-Aryl-2-pyrazinylamino)-1,2,4-trioxanes in Dimethyl Sulfoxide Triggered by Potassiumt-Butoxide

1989 ◽  
Vol 62 (6) ◽  
pp. 2009-2012 ◽  
Author(s):  
Katsunori Teranishi ◽  
Toshio Goto
Keyword(s):  
Excited State ◽  
Dimethyl Sulfoxide ◽  
State Formation ◽  
Substituent Effect ◽  
Singlet Excited State

scholarly journals Ultrafast excited state dynamics and light-switching of [Ru(phen)2(dppz)]2+ in G-quadruplex DNA

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Chunfan Yang ◽  
Qian Zhou ◽  
Zeqing Jiao ◽  
Hongmei Zhao ◽  
Chun-Hua Huang ◽  
...  
Keyword(s):  
Excited State ◽  
State Formation ◽  
Rational Design ◽  
Bound Water ◽  
Binding Modes ◽  
Relaxation Dynamics ◽  
Dark State ◽  
Excited State Dynamics ◽  
G Quadruplex ◽  
Mechanistic Basis

AbstractThe triplet metal to ligand charge transfer (3MLCT) luminescence of ruthenium (II) polypyridyl complexes offers attractive imaging properties, specifically towards the development of sensitive and structure-specific DNA probes. However, rapidly-deactivating dark state formation may compete with 3MLCT luminescence depending on different DNA structures. In this work, by combining femtosecond and nanosecond pump-probe spectroscopy, the 3MLCT relaxation dynamics of [Ru(phen)2(dppz)]2+ (phen = 1,10-phenanthroline, dppz = dipyridophenazine) in two iconic G-quadruplexes has been scrutinized. The binding modes of stacking of dppz ligand on the terminal G-quartet fully and partially are clearly identified based on the biexponential decay dynamics of the 3MLCT luminescence at 620 nm. Interestingly, the inhibited dark state channel in ds-DNA is open in G-quadruplex, featuring an ultrafast picosecond depopulation process from 3MLCT to a dark state. The dark state formation rates are found to be sensitive to the content of water molecules in local G-quadruplex structures, indicating different patterns of bound water. The unique excited state dynamics of [Ru(phen)2(dppz)]2+ in G-quadruplex is deciphered, providing mechanistic basis for the rational design of photoactive ruthenium metal complexes in biological applications.

Amino derivatives of symmetric 1,3,5-triphenylbenzene. Nature of the polar singlet excited state.

1993 ◽  
Vol 176 (1) ◽  
pp. 195-213 ◽  
Author(s):  
G. Verbeek ◽  
S. Depaemelaere ◽  
M. Van der Auweraer ◽  
F.C. De Schryver ◽  
A. Vaes ◽  
...  
Keyword(s):  
Excited State ◽  
Singlet Excited State ◽  
Amino Derivatives ◽  
Derivatives Of

Thionine–graphene oxide covalent hybrid and its interaction with light

2017 ◽  
Vol 19 (22) ◽  
pp. 14412-14423 ◽  
Author(s):  
Ewelina Krzyszkowska ◽  
Justyna Walkowiak-Kulikowska ◽  
Sven Stienen ◽  
Aleksandra Wojcik
Keyword(s):  
Electron Transfer ◽  
Graphene Oxide ◽  
Excited State ◽  
Transfer Process ◽  
Singlet Excited State ◽  
Functionalized Graphene ◽  
Electron Transfer Process ◽  
Functionalized Graphene Oxide ◽  
Back Electron Transfer

Quenching of the thionine singlet excited state in covalently functionalized graphene oxide with an efficient back electron transfer process.

Effects of extending the π-conjugation of the acetylide ligand on the photophysics and reverse saturable absorption of Pt(ii) bipyridine bisacetylide complexes

2016 ◽  
Vol 18 (41) ◽  
pp. 28674-28687 ◽  
Author(s):  
Taotao Lu ◽  
Chengzhe Wang ◽  
Levi Lystrom ◽  
Chengkui Pei ◽  
Svetlana Kilina ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Substituent Effect ◽  
Excited State Absorption ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Triplet Excited State ◽  
Near Ir ◽  
Terminal Substituent ◽  
Acetylide Ligand

Extending the acetylide ligand π-conjugation diminishes the terminal substituent effect on the lowest excited states, but expands the triplet excited-state absorption to the near-IR region.

The photocycloaddition of dibenzoylmethanatoboron difluoride (DBMBF2) with conjugated enones and en-esters

1993 ◽  
Vol 71 (6) ◽  
pp. 846-854 ◽  
Author(s):  
Yuan L. Chow ◽  
Shi-Sen Wang ◽  
Xian-En Cheng
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Ring Opening ◽  
Electron Donors ◽  
Head Orientation ◽  
Singlet Excited State ◽  
Methyl Substitution ◽  
Unsaturated Ketones ◽  
Dibenzoylmethanatoboron Difluoride

Dibenzoylmethanatoboron difluoride (DBMBF2), the BF2 complex of dibenzoylmethane, reacted from its singlet excited state with α,β-unsaturated ketones and esters to give 1,5-diketones by a [2+2] cycloaddition and ring-opening sequence in an analogous pathway to that observed in the photocycloaddition to olefins and dienes. The present photoreaction is unexpected since conjugated enones and en-esters are poor electron donors to comply with the previously proposed charge transfer requirement in DBMBF2 photoreactions. The photocycloaddition to these substrates was highly regioselective and stereoselective, giving the head-to-head orientation, which could be enhanced by α-methyl substitution; β-methyl substitution increased the alternate head-to-tail orientation. The photolysis of a mixture of DBMBF2 and a cyclic enone also caused the latter to dimerize to give head-to-head and head-to-tail dimers in significant yields. These photodimerizations were apparently caused by DBMBF2 sensitization. The mechanism of the sensitization is discussed.

Sign in / Sign up

Export Citation Format

Share Document