Role of Singlet Excited States of Molecular Oxygen in the Quenching of Organic Triplet States

1967 ◽  
Vol 46 (5) ◽  
pp. 1842-1853 ◽  
Author(s):  
Kenji Kawaoka ◽  
A. U. Khan ◽  
David R. Kearns
Keyword(s):  
Molecular Oxygen ◽  
Excited States ◽  
Triplet States

scholarly journals Erratum: Role of Singlet Excited States of Molecular Oxygen in the Quenching of Organic Triplet States

1967 ◽  
Vol 47 (5) ◽  
pp. 1883-1884 ◽  
Author(s):  
Kenji Kawaoka ◽  
A. U. Khan ◽  
David R. Kearns
Keyword(s):  
Molecular Oxygen ◽  
Excited States ◽  
Triplet States

Restriction of Access to Dark State: A New Mechanistic Model for Heteroatom-Containing AIE Systems

2019 ◽  
Author(s):  
Yujie Tu ◽  
Junkai Liu ◽  
Haoke Zhang ◽  
Qian Peng ◽  
Jacky W. Y. Lam ◽  
...  
Keyword(s):  
Excited States ◽  
Radiative Decay ◽  
Molecular Design ◽  
Mechanistic Model ◽  
Zinc Ion ◽  
Easy Access ◽  
Triplet States ◽  
Dark State ◽  
Ion Probe ◽  
Π State

Aggregation-induced emission (AIE) is an unusual photophysical phenomenon and provides an effective and advantageous strategy for the design of highly emissive materials in versatile applications such as sensing, imaging, and theragnosis. "Restriction of intramolecular motion" is the well-recognized working mechanism of AIE and have guided the molecular design of most AIE materials. However, it sometimes fails to be workable to some heteroatom-containing systems. Herein, in this work, we take more than one excited state into account and specify a mechanism –"restriction of access to dark state (RADS)" – to explain the AIE effect of heteroatom-containing molecules. An anthracene-based zinc ion probe named APA is chosen as the model compound, whose weak fluorescence in solution is ascribed to the easy access from the bright (π,π*) state to the closelying dark (n,π*) state caused by the strong vibronic coupling of the two excited states. By either metal complexation or aggregation, the dark state is less accessible due to the restriction of the molecular motion leading to the dark state and elevation of the dark state energy, thus the emission of the bright state is restored. RADS is found to be powerful in elucidating the photophysics of AIE materials with excited states which favor non-radiative decay, including overlap-forbidden states such as (n,π*) and CT states, spin-forbidden triplet states, which commonly exist in heteroatom-containing molecules.

Role of Triplet States in the Photodynamics of Aniline

2021 ◽  
Vol 143 (15) ◽  
pp. 5878-5889
Author(s):  
Aleksandr O. Lykhin ◽  
Donald G. Truhlar ◽  
Laura Gagliardi
Keyword(s):  
Triplet States

scholarly journals Exploitation of Baird Aromaticity and Clar’s Rule for Tuning the Triplet Energies of Polycyclic Aromatic Hydrocarbons

Chemistry ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 532-549
Author(s):  
Felix Plasser
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Excited States ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Materials Science ◽  
Chemical Shifts ◽  
Qualitative Description ◽  
Triplet States ◽  
Excitation Energies ◽  
Polycyclic Aromatic

Polycyclic aromatic hydrocarbons (PAH) are a prominent substance class with a variety of applications in molecular materials science. Their electronic properties crucially depend on the bond topology in ways that are often highly non-intuitive. Here, we study, using density functional theory, the triplet states of four biphenylene-derived PAHs finding dramatically different triplet excitation energies for closely related isomeric structures. These differences are rationalised using a qualitative description of Clar sextets and Baird quartets, quantified in terms of nucleus independent chemical shifts, and represented graphically through a recently developed method for visualising chemical shielding tensors (VIST). The results are further interpreted in terms of a 2D rigid rotor model of aromaticity and through an analysis of the natural transition orbitals involved in the triplet excited states showing good consistency between the different viewpoints. We believe that this work constitutes an important step in consolidating these varying viewpoints of electronically excited states.

The role of zero-field splitting and π-stacking interaction of different nitrogen-donor ligands on the optical properties of luminescent rhenium tricarbonyl complexes

2021 ◽  
Author(s):  
Plinio Cantero-López ◽  
Yoan Hidalgo-Rosa ◽  
Zoraida Sandoval-Olivares ◽  
Julián Santoyo-Flores ◽  
Pablo Mella ◽  
...  
Keyword(s):  
Excited States ◽  
Coordination Compounds ◽  
Donor Ligands ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Nitrogen Donor Ligands ◽  
Nitrogen Donor ◽  
Π Stacking Interaction ◽  
Rhenium Tricarbonyl

Rhenium tricarbonyl complexes are one of the most important classes of coordination compounds in inorganic chemistry. Exploring their luminescent excited states, lowest singlet (S1), and the lowest triplet (T1), is...

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