Article
Chemistry, Physical
Yifan Quan, Nemanja Niketic, Jakob M. Steiner, Tim R. Eichhorn, W. Tom Wenckebach, Patrick Hautle
Summary: A general theory is proposed for the photo-excitation dynamics of transient, paramagnetic triplet states of aromatic molecules in a molecular host crystal under pulsed laser irradiation. This theory is applied to the pentacene-doped naphthalene single crystal system, where the photo-excitation of pentacene results in a non-equilibrium population of intermediate electronic triplet states. The theoretical model allows the extraction of crucial parameters for quantitative investigations of spin system dynamics.
Article
Chemistry, Physical
Gajadhar Joshi, Ryan D. D. Dill, Karl J. J. Thorley, John E. E. Anthony, Obadiah G. G. Reid, Justin C. C. Johnson
Summary: We characterize the change in electron spin magnetic resonance in the photoluminescence intensity for a tailored organic molecular crystal. Resonant transitions for both triplet and quintet spin sublevel populations are observed, revealing their optical sensitivity and providing zero-field parameters for each. The data suggests significant spin polarization and orientation selectivity in this system.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Patrick A. Robertson, Hannah M. Bishop, Andrew J. Orr-Ewing
Summary: The study investigates the effects of dissolved metal salts on the excited-state dynamics of acetophenone in solution using ultrafast transient absorption spectroscopy. The findings show that coordination to metal ions alters the excited-state energies and dynamics of the photosensitizer, which could potentially modify the photochemistry of homogeneous photocatalytic systems.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Review
Chemistry, Multidisciplinary
Yuanyuan Fan, Qianqian Li, Zhen Li
Summary: This review presents the recent progress of in vitro and in vivo afterglow bioimaging using organic RTP materials. The strategies of molecular design and controlling methods of molecular packing are summarized, with emphasis on high intensity, ultralong lifetimes and red-shifted wavelengths of phosphorescence emission.
SCIENCE CHINA-CHEMISTRY
(2023)
Article
Chemistry, Organic
Veronika Schmalz, Ulrich Koert
Summary: This study presents a light-induced intramolecular hydroacylation process that selectively forms a six-membered ring to produce 1-tetralones from ortho-allylbenzaldehydes. The reaction proceeds at 365 nm, ambient temperature, and without any additives. The proposed mechanism involves a light-induced hydrogen atom transfer and radical recombination process. This efficient photo-hydroacylation provides a valuable method for the synthesis of various tetralone scaffolds through light activation.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Organic
Veronika Schmalz, Ulrich Koert
Summary: This study presents a light-induced intramolecular hydroacylation reaction that selectively forms a six-membered ring in 1-tetralones through light activation. The reaction proceeds at 365 nm, ambient temperature, and additive-free conditions, and the proposed mechanism involves a light-induced 1,5-hydrogen atom transfer and radical recombination process. Deuteration and radical-clock experiments support the mechanism.
ORGANIC CHEMISTRY FRONTIERS
(2023)
Article
Chemistry, Multidisciplinary
Saiya Fujiwara, Naoto Matsumoto, Koki Nishimura, Nobuo Kimizuka, Kenichiro Tateishi, Tomohiro Uesaka, Nobuhiro Yanai
Summary: Utilizing the induced-fit-type structural transformation of a metal-organic framework (MOF), we demonstrate DNP of guest molecules at around room temperature, resulting in enhanced NMR signal.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Multidisciplinary
Ben J. Tickner, Vladimir V. Zhivonitko
Summary: Parahydrogen-induced polarisation (PHIP) is a technique that enhances nuclear magnetic resonance (NMR) signals by utilizing the chemical reactions of parahydrogen (para-H-2). Recent advances in the development of novel homogeneous catalysts have allowed for the hyperpolarisation of a wider range of target molecules. This technique has various applications in NMR reaction monitoring, mechanistic elucidation, biomedical imaging, and more.
Article
Chemistry, Physical
Ze Yu, Qiuying Li, Qian Ma, Wenpeng Ye, Zhongfu An, Huili Ma
Summary: Electro-fluorescent materials with 100% internal quantum efficiency and short fluorescence lifetimes can be achieved by harvesting high-lying triplet excitons. In this study, two excited-state descriptors, triplet-triplet energy gap ΔETT and oscillator strength f, were established to characterize exciton utilization efficiency, photoluminescence quantum yield, and fluorescence lifetime. High-throughput screening of over 5000 fluorophores predicted 19 candidate molecules with a high IQE (>90%), guided by these descriptors.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Xin Cheng, Huan Hu, Yu Wu, Zhimin Ma, Zhiyong Ma
Summary: We have designed a novel ESIPT mechanophore (HBIA-2OH) through a three-step synthesis. When connected to polyurethane, it exhibits unique photo-gated mechanochromism, achieved through photo-induced formation and force-induced breaking of intramolecular hydrogen bonds during excited-state intramolecular proton transfer (ESIPT). As a control, HBIA@PU shows no response to photo/force. Therefore, HBIA-2OH is a rare mechanophore with photo-gated mechanochromism.
CHEMICAL COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
Xi Chen, Noreen Rehmat, Ivan V. Kurganskii, Partha Maity, Ayhan Elmali, Jianzhang Zhao, Ahmet Karatay, Omar F. Mohammed, Matvey V. Fedin
Summary: Bodipy (BDP)-perylenebisimide (PBI) donor-acceptor dyads/triad were synthesized to investigate the spin-orbit charge-transfer intersystem crossing (SOCT-ISC). Different quantum yields of singlet oxygen were observed for the dyads/triad, and various processes including FRET, CS, CR, and TTET were observed in the excited state dynamics. Time-resolved electron paramagnetic resonance spectroscopy revealed the involvement of both radical pair ISC and SOCT-ISC in the intersystem crossing. The triad BDP-PBI-2 showed an unusual electron spin polarization pattern of (e, e, e, e, e, e) in the triplet state formed via the RP ISC mechanism.
CHEMISTRY-A EUROPEAN JOURNAL
(2023)
Article
Chemistry, Multidisciplinary
German E. Pieslinger, Ivana Ramirez-Wierzbicki, Alejandro Cadranel
Summary: The excited-state version of the Creutz-Taube ion prepared via visible light excitation exhibits strong thermalization and electron delocalization properties. This state has a nanosecond lifetime and can be utilized for intermolecular electron transfer.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Applied
Jie Ma, Jinlong Li, Rui Yang, Weijian Xue, Qingxia Wang, Shenmiao Li
Summary: The study revealed that N-1 to N-5 exhibit significantly red-shifted UV-vis absorption and emission properties, with N-1 demonstrating dual emission, confirming their ESIPT characteristics. All compounds generated triplet excited states, with N-3 and N-4 showing longer triplet excited state lifetimes and higher photooxidative abilities than the other compounds.
Article
Energy & Fuels
Kazuki Kohzuki, Rei Shirouchi, Shin-ichiro Natsuda, Toshiharu Saito, Yuji Sakamoto, Yasunari Tamai
Summary: Suppressing charge recombination is crucial for enhancing the power conversion efficiency of organic solar cells (OSCs). The formation of both singlet and triplet charge transfer (CT) states in OSCs indicates that charge recombination via the triplet excited state is the main pathway for deactivation. However, it has been shown that charge separation from triplet excitons can occur in nonfullerene acceptor (NFA)-based OSCs, emphasizing the significance of minimizing the energy difference between singlet and triplet excited states of NFAs to suppress charge recombination.
Article
Chemistry, Multidisciplinary
Silvia Escayola, Claire Tonnele, Eduard Matito, Albert Poater, Henrik Ottosson, Miquel Sola, David Casanova
Summary: Pro-aromatic molecules have distinct diradicaloid and T-1 states with potential Baird aromaticity, which can be designed using strategies involving electron-donating substituents on small conjugated rings, electron withdrawing substituents on small exocyclic groups, or electron-deficient conjugated rings with exocyclic electron-donor substitution.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)