scholarly journals Direct Evidence of an Excited-State Triplet Species upon Photoactivation of the Chlorophyll Precursor Protochlorophyllide

2017 ◽  
Vol 8 (6) ◽  
pp. 1219-1223 ◽  
Author(s):  
Guillem Brandariz-de-Pedro ◽  
Derren J. Heyes ◽  
Samantha J. O. Hardman ◽  
Muralidharan Shanmugam ◽  
Alex R. Jones ◽  
...  
Keyword(s):  
Excited State ◽  
Direct Evidence ◽  
Chlorophyll Precursor

scholarly journals Direct Visualization of Energy-transferred Excited State in Eu Complex

2014 ◽  
Vol 70 (a1) ◽  
pp. C102-C102 ◽  
Author(s):  
Kunihisa Sugimoto ◽  
Akihiko Fujiwara ◽  
Masaki Takata ◽  
Hiroshi Tanaka ◽  
Miki Hasegawa
Keyword(s):  
Energy Transfer ◽  
Excited State ◽  
Charge Density ◽  
Electrostatic Potential ◽  
Ground State ◽  
Direct Evidence ◽  
Entropy Method ◽  
Direct Visualization ◽  
Band Shape ◽  
Hexadentate Ligand

Highly luminescent lanthanide (Ln) complexes have attracted much attention because Ln3+ions show long-lived ff-emissions with narrow band shape. Their unique photo-optical properties are promising for the design of light-emitting materials and sensing devices. Although the ff-emissions are essentially weak because of Laporte forbidden, chelate ligands is effective to strengthen the intramolecular energy transfer from photo-excited organic ligands to Ln3+ions. The direct evidence of energy transfer from ligands to Ln3+and details of excited state, however, are still veiled. Here, we report direct visualization of energy-transferred excited state in Eu complex with a hexadentate ligand (L) consisting of two bipyridine moieties bridged by an ethylendiamine unit, [Eu3+(L)(NO3)2](PF6) (Eu(L))[1] by Maximum Entropy Method (MEM) charge density[2] and electrostatic potential analysis[3] based on SR X-ray diffraction. First, we confirmed that the electron numbers of Eu and ligand L in the excited state are the same as those in the ground state, which is a direct evidence of energy transfer instead of charge transfer. Next, we observed charge re-distribution in the Eu ion and the ligand L. The electrostatic potential distributions calculated using MEM charge density give an experimental evidence for the existence of polarization of ligand L both in the ground and photo-excited states. The orientation polarization in the ground state changed during pumping at 315 nm, and the charge re-distribution are qualitatively consistent with a theoretical prediction. This characteristic luminescence behavior based on the energy relaxation process have not been detected by fundamental crystal structural analysis. We have succeeded in visualization of subtle but important change due to energy transfer in the mononuclear Europium complex with hexadentate ligand at the first time.

Organic polymorphs with fluorescence switching: direct evidence for mechanical and thermal modulation of excited state transitions

2019 ◽  
Vol 55 (26) ◽  
pp. 3749-3752 ◽  
Author(s):  
Shan Jiang ◽  
Jiayu Wang ◽  
Qingkai Qi ◽  
Jingyu Qian ◽  
Bin Xu ◽  
...  
Keyword(s):  
Excited State ◽  
Solid State ◽  
Direct Observation ◽  
Direct Evidence ◽  
State Transition ◽  
State Transitions ◽  
Thermal Modulation ◽  
Fluorescence Switching ◽  
Thermal Stimuli

Herein, we provide a direct observation of the modulation of the excited state transition under mechanical and thermal stimuli in the solid state by two organic polymorphs based on a tetraphenylethene derivative (APMOB).

Direct Evidence of Significantly Different Chemical Behavior and Excited-State Dynamics of 1,7- and 1,6-Regioisomers of Pyrrolidinyl-Substituted Perylene Diimide

2013 ◽  
Vol 19 (21) ◽  
pp. 6791-6806 ◽  
Author(s):  
Rajeev K. Dubey ◽  
Marja Niemi ◽  
Kimmo Kaunisto ◽  
Alexander Efimov ◽  
Nikolai V. Tkachenko ◽  
...  
Keyword(s):  
Excited State ◽  
Direct Evidence ◽  
Perylene Diimide ◽  
Chemical Behavior ◽  
Excited State Dynamics
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