Article
Chemistry, Multidisciplinary
Han Li, Oliver S. Wenger
Summary: Our study demonstrates the concept that single excitation of the two-electron reduced forms of perylene diimides (PDIs) with green photons can produce excited states with similar or greater reducing power than the shorter-lived excited states of PDI radical monoanions. By performing multi-electron reduction of a photocatalyst with a sacrificial reagent before irradiation with low-energy photons, we can generate highly reactive excited states for photocatalytic reactions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Review
Chemistry, Multidisciplinary
Narayan Sinha, Polina Yaltseva, Oliver S. Wenger
Summary: The nephelauxetic effect, which refers to the expansion of d-orbitals as a result of metal-ligand bond covalence, has been recognized for its importance in the design of new photoactive complexes using first-row transition metals. This effect can significantly impact the photophysical properties of 3d metal complexes in solution at room temperature. By exploiting the nephelauxetic effect, red luminescence in Cr-III and Mn-IV complexes has been shifted to the near-infrared spectral region, while charge-transfer excited states in Fe-II and Co-III complexes have been stabilized, improving their properties and application potential.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Yu-Wu Zhong
Summary: This review focuses on the recent progress in the design and preparations of photofunctional metal complexes and related materials from the perspective of coordination molecular engineering. The research group's favorite topic is the ruthenium-triarylamine conjugated system. The most important qualities for scientific research are considered to be honesty, curiosity, and persistence, while balancing work and family life is achieved through time management and prioritization of daily tasks.
CHINESE JOURNAL OF CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Jin Tanaka, Yuki Nagashima, Antonio Junio Araujo Dias, Ken Tanaka
Summary: A novel photoinduced in situ reduction reaction of half-sandwich metal [Rh(III)] complexes to low-valent anionic metal [Rh(II)] ate complexes has been reported, enabling room temperature ortho-C-H borylation of arenes. This strategy was facilitated by using a functionalized cyclopentadienyl (Cp-A3) Rh(III) catalyst developed by the researchers.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Inorganic & Nuclear
Meiqiong Tang, Lee Cameron, Eve M. Poland, Li-Juan Yu, Stephen A. Moggach, Rebecca O. Fuller, Hai Huang, Jianwei Sun, Stuart C. Thickett, Massimiliano Massi, Michelle L. Coote, Curtis C. Ho, Alex C. Bissember
Summary: This report presents the synthesis and characterization of a family of chromium, molybdenum, tungsten, manganese, and iron complexes with N-heterocyclic carbene and carbonyl supporting ligands. The properties of these complexes were studied using experiment and theory, including their solid-state, spectroscopic, electrochemical, and photophysical properties. It was found that these complexes undergo decarbonylation when exposed to ultraviolet light.
INORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Rohit Kumar, Sanjukta Pahar, Joy Chatterjee, Soumya Ranjan Dash, Rajesh G. Gonnade, Kumar Vanka, Sakya S. Sen
Summary: In this study, two magnesium complexes supported by 2,2'-pyridylpyrrolide ligands (PyPyrH) were reported. These complexes exhibit bright luminescence with quantum yields of 22% and 14% in the solid state, respectively. Theoretical calculations indicate that their emissive properties originate from intra- and inter-ligand charge transfer.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Laura Stein, Cui Wang, Christoph Foerster, Ute Resch-Genger, Katja Heinze
Summary: Chromium (III) complexes exhibit phosphorescence under anaerobic conditions but are quenched in the presence of oxygen. This study explores the use of sterically demanding ligands to shield the chromium (III) center from oxygen, enabling luminescence applications of these complexes under aerobic conditions. Optimal sterically shielded complexes showed high photoluminescence quantum yields and longer excited state lifetimes, demonstrating the potential of this ligand design approach.
DALTON TRANSACTIONS
(2022)
Article
Chemistry, Inorganic & Nuclear
Svetlana A. Katkova, Daria O. Kozina, Kristina S. Kisel, Maria A. Sandzhieva, Dmitriy A. Tarvanen, Sergey V. Makarov, Vitaly V. Porsev, Sergey P. Tunik, Mikhail A. Kinzhalov
Summary: A series of cyclometalated platinum(ii) complexes with acyclic diaminocarbene (ADC) ancillary ligands were designed and synthesized. Their photophysical properties were investigated both experimentally and theoretically. The complexes showed green phosphorescence with high quantum efficiency of up to 45% in 2 wt% doped PMMA film at room temperature. These complexes were further utilized as light-emitting dopants for OLED fabrication. The resulting devices demonstrated green emission with a maximum current efficiency of 2.9 cd A(-1) and a luminance of 2700 cd m(-2), highlighting the potential of these cyclometalated platinum(ii) complexes as efficient green emitters for OLED devices.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Multidisciplinary
Matthias Dorn, Jens Kalmbach, Pit Boden, Ayla Kruse, Chahinez Dab, Christian Reber, Gereon Niedner-Schatteburg, Stefan Lochbrunner, Markus Gerhards, Michael Seitz, Katja Heinze
Summary: Luminescent transition metal complexes with Earth-abundant metals are rare, especially those with 3d transition metals showing near-infrared emission. This study investigates the excited state dynamics of a d(2)-vanadium(iii) complex, providing insights for designing molecular materials with spin-flip luminescence and photoinduced metal-ligand bond homolysis.
Article
Chemistry, Inorganic & Nuclear
Yang Cheng, Qingqing Yang, Jiang He, Wenjie Zou, Keyu Liao, Xiaoyong Chang, Chao Zou, Wei Lu
Summary: This article introduces a series of substituted anionic ligands containing Cr(iii) complexes, which exhibit phosphorescent properties in degassed fluid solutions.
DALTON TRANSACTIONS
(2023)
Article
Biochemistry & Molecular Biology
Jack Saltiel, Sumesh B. Krishnan, Shipra Gupta, Anjan Chakraborty, Edwin F. Hilinski, Xinsong Lin
Summary: Cholesta-5,7,9(11)-trien-3 beta-ol (9,11-dehydroprovitamin D-3, CTL) is used as a fluorescent probe to track the presence and migration of cholesterol in vivo. The photochemistry and photophysics of CTL in degassed and air-saturated tetrahydrofuran (THF) solution, an aprotic solvent, have been studied. The zwitterionic nature of the singlet excited state, (CTL)-C-1*, is revealed in ethanol, a protic solvent. In the presence of air, peroxide formation is a major reaction channel, similar to THF.
Article
Chemistry, Multidisciplinary
Sapna Ahuja, Sruthy Baburaj, Lakshmy Kannadi Valloli, Sarvar Aminovich Rakhimov, Kavyasree Manal, Aakrati Kushwaha, Steffen Jockusch, Malcolm D. E. Forbes, Jayaraman Sivaguru
Summary: Aryl-maleimides undergo a novel [2+4]-photodimerization instead of the expected [2+2]-photodimerization, and the stereochemistry of the photodimer formed complements the product observed under thermal conditions.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Multidisciplinary
Christian Ley, Antoine Siedel, Tony Bertaux, Celine Croutxe-Barghorn, Xavier Allonas
Summary: Photobase generators are species that can catalyze various reactions such as thiol-Michael, thiol-isocyanate, and ring-opening polymerization reactions. However, the compounds currently available have complex syntheses and low quantum yields. To address these issues, photobase generators based on the photodecarboxylation reaction were developed and studied. The photochemistry and photophysics of two xanthone photobase, their carboxylic acid precursors, and their photoproducts were synthesized and investigated to understand the mechanism of photobase generation. Accurate quantum yields of triplet states and photobase generation were determined. The impact of the intermediate radical before the base release was also demonstrated. The photophysics of the photobase was characterized using femtosecond spectroscopy, revealing a rate constant of 2.2x10(9) s(-1) for the photodecarboxylation process occurring from the second excited triplet state.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Chemistry, Physical
Avinash Chettri, Kilian R. A. Schneider, Houston D. Cole, John A. Roque, Colin G. Cameron, Sherri A. McFarland, Benjamin Dietzek
Summary: The photophysical properties of a family of Ru(II) complexes, Ru-ip-nT, designed as photosensitizers for photodynamic therapy (PDT), were explored. The length of the thiophene chain in these complexes impacts the ultrafast photoinduced dynamics and the photophysics of the complexes, ultimately affecting their photocytotoxicity as photosensitizers for PDT, with Ru-ip-3T showing potent photocytotoxicity against bladder cancer.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Multidisciplinary
Iria Bolano Losada, Petter Persson
Summary: The excited state evolution of a rhodium(III) complex has been theoretically investigated to understand the light-driven activation of high-energy metal centered states. Ab initio molecular dynamics simulations reveal the significance of asymmetric motion for the activated crossover process on picosecond timescales. The simulations also show that entropic differences favor the forward crossover process. The interplay between structural and electronic factors in the dynamics and its implications for photoinduced generation of high-energy states are discussed.
Article
Chemistry, Multidisciplinary
Hai-Xu Wang, Liangliang Wu, Bin Zheng, Lili Du, Wai-Pong To, Cheng-Hoi Ko, David Lee Phillips, Chi-Ming Che
Summary: In this study, the hydrogen atom transfer reactivity of an Fe porphyrin nitrido species towards C-H substrates was investigated using nanosecond laser flash photolysis. It was found that C-H bonds with bond dissociation enthalpies of up to approximately 84 kcal mol(-1) could be activated, with second-order rate constants on the order of 10(2)-10(4) s(-1) m(-1). The Fe-amido product formed after hydrogen atom transfer could further release ammonia upon protonation.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Organic
Siyuan Guo, Kong Ching Wong, Stephan Scheeff, Zhuo He, Wesley Ting Kwok Chan, Kam-Hung Low, Pauline Chiu
Summary: The copper-catalyzed reductive Ireland-Claisen rearrangement led to the synthesis of diastereomeric products with divergent selectivity, utilizing silanes or pinacolborane as reducing agents and triethylphosphite as a ligand. The mechanism studies showed that silyl and boron enolates underwent a stereospecific rearrangement via a chairlike transition state to afford the Claisen rearrangement products.
JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Multidisciplinary
Yin Zheng, Suihan Zhang, Kam-Hung Low, Weiwei Zi, Zhongxing Huang
Summary: This study reports a reductive desymmetrization of halomalonic esters using dinuclear zinc catalysts. The resulting α-halo-β-hydroxyesters serve as important intermediates for the synthesis of drug analogs and polyhalogenated monoterpenes.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Inorganic & Nuclear
Kwok-Chung Law, Zhou Tang, Liangliang Wu, Qingyun Wan, Wai-Pong To, Xiaoyong Chang, Kam-Hung Low, Yungen Liu, Chi-Ming Che
Summary: A series of cyclometalated Fe(II/III) and Ru(II/III) complexes with a tetradentate dianionic [O<^>N<^>C<^>N] ligand were synthesized and characterized. The properties of the ligand significantly affect the spin state, absorption, and emission of the complexes, as revealed by various experiments and theoretical calculations.
Article
Nanoscience & Nanotechnology
Jian-Gong Yang, Xiu-Fang Song, Gang Cheng, Siping Wu, Xingyu Feng, Ganglong Cui, Wai-Pong To, Xiaoyong Chang, Yong Chen, Chi-Ming Che, Chuluo Yang, Kai Li
Summary: In this study, a new class of carbene-Au-carbazolate complexes with twisted D-A conformation were developed. The presence of large aromatic substituents restricted the rotation of the Au-N bond, resulting in a twisted orientation. The twisted conformation decreased the energy gap between the lowest singlet excited state and the triplet manifold, and accelerated the reverse intersystem crossing rate, leading to improved delayed fluorescence efficiency.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Chemistry, Multidisciplinary
Yueyao Chen, Jesse Ling, Angus B. Keto, Yun He, Kam-Hung Low, Elizabeth H. Krenske, Pauline Chiu
Summary: Epoxy and aziridinyl enolsilanes can react as oxyallylic cation equivalents in highly selective and stereoselective intramolecular (3+2) cycloadditions. Computational studies suggest that the stepwise reaction involves the conformational flexibility of the intermediate, which determines the formation of (3+2) cycloadducts. This method can be used for the synthesis of densely functionalized trans-hydrindane scaffolds.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Juraj Ovcar, Tik Lun Leung, Luca Grisanti, Zeljko Skoko, Martina Vrankic, Kam-Hung Low, Shixun Wang, Pei-Ying You, Hyeyoung Ahn, Ivor Loncaric, Aleksandra B. Djurisic, Jasminka Popovic
Summary: This study investigates the influence of spacer cations on the structure of two-dimensional perovskites. The results show that the branched tert-butyl ammonium spacer cation can form a stable Ruddlesden-Popper structure when the inorganic pocket is designed appropriately.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Zongshang Li, Ke Xiao, Qingyun Wan, Rui Tang, Kam-Hung Low, Xiaodong Cui, Chi-Ming Che
Summary: The introduction of multiple kinetic aggregation states (Aggs) into the self-assembly pathway can increase the complexity and flexibility of the self-assemblies. This was achieved by using a series of chiral and achiral d(10) Au-I bis(N-heterocyclic carbene, NHC) complexes, where the achiral complex could undergo self-assembly with multiple kinetic Aggs. The chiral Au-I self-assemblies exhibited nonlinear optical response of second harmonic generation (SHG) and could function as optical waveguides with strong emission polarization, while these properties were absent in the achiral analogue.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Pharmacology & Pharmacy
Si Nga Wong, Kam-Hung Low, Yi Lam Poon, Xinyue Zhang, Ho Wan Chan, Shing Fung Chow
Summary: This study successfully synthesized a cocrystal of remdesivir (RDV) with salicylic acid (SA) through liquid-assisted grinding and thermal annealing. The molecular structure of RDV-SA was resolved through powder X-ray analysis. RDV-SA was further developed as inhaled dry powders for potential COVID-19 therapy, displaying improved release in simulated lung fluid compared to raw RDV.
INTERNATIONAL JOURNAL OF PHARMACEUTICS
(2023)
Article
Chemistry, Inorganic & Nuclear
Chen Wu, Kam-Hung Low, Vonika Ka-Man Au
Summary: A class of alkaline earth metal-based metal-organic frameworks (MOFs) named NDCMOF(Ca) and NDCMOF(Sr) were synthesized using 2,6-naphthalenedicarboxylic acid (NDC) as the linker. These MOFs were able to remove copper(II) ions (Cu2+) from aqueous systems and exhibited comparable adsorption capacities to other related MOFs and porous materials. Additionally, they displayed blue luminescence in the solid state at room temperature upon UV light excitation, which could be quenched after the adsorption of Cu2+ ions, making them versatile adsorbents and sensors for Cu2+ in water.
JOURNAL OF SOLID STATE CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Xiaoyong Mo, Yulin Deng, Samuel Kin-Man Lai, Xutao Gao, Hung-Ling Yu, Kam-Hung Low, Zhengxiao Guo, Heng-Liang Wu, Ho Yu Au-Yeung, Edmund C. M. Tse
Summary: Efficient O2 reduction reaction (ORR) for selective H2O generation can be achieved by introducing the concept of mechanical interlocking to Cu complexes. These interlocked catenane ligands can control O2 binding mode, promote electron transfer, and enhance the selectivity and activity of ORR.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Si Nga Wong, Kam-Hung Low, Jingwen Weng, Ho Wan Chan, Shing Fung Chow
Summary: In this study, two DEX cocrystals with benzenediols (catechol and resorcinol) were successfully synthesized for the first time via mechanical treatment, providing a new approach to expand the solid-state landscape and improve the pharmaceutical properties of DEX.
Article
Chemistry, Multidisciplinary
Jing Xiang, Jiang Zhu, Miaomiao Zhou, Lu-Lu Liu, Li-Xin Wang, Min Peng, Bi-Shun Hou, Shek-Man Yiu, Wai-Pong To, Chi-Ming Che, Kai-Chung Lau, Tai-Chu Lau
Summary: The photoreactions of a luminescent osmium(VI) nitrido complex, [Os-VI (N)(L)(CN)(3)](-) (OsN, HL = 2-(2-hydroxy-5-nitrophenyl)benzoxazole), with catechol (H(2)Cat) and hydroquinone (H(2)Q) result in the cleavage of strong C-OH bonds in dihydroxybenzenes and the conversion of coordinated cyanide to carbon monoxide.
CHEMICAL COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Tony Ho-Ching Fung, Cheok-Lam Wong, Wai-Kit Tang, Ming-Yi Leung, Kam-Hung Low, Vivian Wing-Wah Yam
Summary: A new series of four-coordinate boron compounds with reversible photochromic properties have been successfully designed and synthesized. The photochromic behavior can be tuned by modifying the ancillary ligand.
CHEMICAL COMMUNICATIONS
(2022)