A combination of cryogenic UV-vis and CD spectroscopy and transient absorption spectroscopy at ambient temperature is used to study a new class of unidirectional rotary molecular motors. Stabilization of unstable intermediates is achieved below 95 K in propane solution for the structure with the fastest rotation rate, and below this temperature measurements on the rate limiting step in the rotation cycle can be performed to obtain activation parameters. The results are compared to measurements at ambient temperature using transient absorption spectroscopy, which show that behavior of these motors is similar over the full temperature range investigated, thereby allowing a maximum rotation rate of 3 MHz at room temperature under suitable irradiation conditions.
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http://dx.doi.org/10.1021/ja8037245 | DOI Listing |
J Phys Chem A
January 2025
Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States.
Given their molecular properties and electronic structure, graphyne and graphdiyne are promising materials with numerous applications in different fields of material science. Dehydrobenzoannules (DBAs) are candidates that can serve as building blocks for synthesizing and designing new 2D carbon allotropes; however, only a few graphynes have been produced on a practical scale. Herein, we present our investigation of three DBAs, which serve as a model to understand the relationship between the structure and property, contributing to 2D carbon allotropes' rational design and synthetic effort.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Chemistry, University of Colorado Boulder, 215 UCB, Boulder, Colorado 80309, USA.
Nanotechnology
January 2025
Changchun University of Science and Technology, 7089 Weixing Road, Chaoyang District, Changchun City, Jilin Province, Changchun, 130022, CHINA.
Quasi-two-dimensional nanosheets exhibit novel properties and promising applications in optoelectronic flexible devices. Research on non-layered III-V semiconductor nanosheets has been constrained by their covalent bonding connections. In this study, GaAs/AlGaAs heterojunction nanosheets were prepared by releasing an epitaxial layer, and their optical properties were investigated by adopting steady-state and transient absorption spectroscopy.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, United States.
Modulation of singlet and triplet energy transfer from excited semiconductor nanocrystals to attached dye molecules remains an important criterion for the design of light-harvesting assemblies. Whereas one can consider the selection of donor and acceptor with favorable energetics, spectral overlap, and kinetics of energy transfer as a means to direct the singlet and triplet energy transfer pathways, it is not obvious how to control the singlet and triplet characteristics of the donor semiconductor nanocrystal itself. By doping CsPb(ClBr) nanocrystals with Mn, we have now succeeded in increasing the triplet characteristics of semiconductor nanocrystals.
View Article and Find Full Text PDFNat Commun
January 2025
Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, PR China.
The H-evolution kinetics play a pivotal role in governing the photocatalytic hydrogen-evolution process. However, achieving precise regulation of the H-adsorption and H-desorption equilibrium (H/H) still remains a great challenge. Herein, we propose a fine-tuning d-p hybridization strategy to precisely optimize the H/H kinetics in a Ni-B modified CdS photocatalyst (Ni-B/CdS).
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