The phenomenon of formation of two isomers, yellow and orange, of the cyclometalated Ru(II) complex, [Ru(o-C₆H₄-py)(MeCN)₄]⁺, was investigated by EELS spectroscopy and theoretical calculations. Both forms show very similar structures and spectroscopic properties, but slight differences in X-ray data and absorption between them were noted. No double minimum on the potential energy surface was found and thus these two forms cannot be considered as bond stretching isomers. However, the DFT study revealed the change in the hybridization of the carbon in trans-position of one of acetonitrile ligands. This effect can be responsible for the difference in colour. The results of the theoretical modelling coincide well with the experimental EELS data.
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http://dx.doi.org/10.3390/molecules17010034 | DOI Listing |
ACS Omega
January 2025
Department of New Energy Science and Engineering, Xiamen University Malaysia, Sepang 43900, Malaysia.
Using the free energy of hydrogen adsorption (Δ ) as the indicator, five borophene phases are previously shown to possess high catalytic activity for the hydrogen evolution reaction (HER). On these borophene phases, we investigate the role of the coordination number (CN = 4, 5, 6) of the adsorption sites and the puckering of the adsorption site. CN is discovered to have a profound effect on the Δ distribution, charge, and puckering height () of adsorption sites.
View Article and Find Full Text PDFRSC Adv
January 2025
Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering & Technology (BUET) Dhaka Bangladesh
ACS Nano
January 2025
School of Information Science and Technology and Department of Optical Science and Engineering and Key Laboratory of Micro and Nano Photonic Structures (MOE), Fudan University, Shanghai 200433, China.
The formation of large polarons resulting from the Fröhlich coupling of photogenerated carriers with the polarized crystal lattice is considered crucial in shaping the outstanding optoelectronic properties in hybrid organic-inorganic perovskite crystals. Until now, the initial polaron dynamics after photoexcitation have remained elusive in the hybrid perovskite system. Here, based on the terahertz time-domain spectroscopy and optical-pump terahertz probe, we access the nature of interplay between photoexcited unbound charge carriers and optical phonons in MAPbBr within the initial 5 ps after excitation and have demonstrated the simultaneous existence of both electron- and hole-polarons, together with the photogenerated carrier dynamic process.
View Article and Find Full Text PDFJ Comput Chem
January 2025
Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London, UK.
We report nonadiabatic dynamics computations on CH initiated on a coherent superposition of the five lowest cationic states, employing the Quantum Ehrenfest method. In addition to the totally symmetric carbon-carbon double bond stretch and carbon-hydrogen stretches, we see that the three non-totally symmetric modes become stimulated; torsion and three different CH stretching patterns. Thus, a coherent superposition of states, of the type involved in an attochemistry experiment, leads to the stimulation of specific non-totally symmetric motions.
View Article and Find Full Text PDFMolecules
December 2024
Department of Biological and Chemical Sciences, The University of the West Indies, Cave Hill Campus, Wanstead P.O. Box 64, Barbados.
A computational study of X-H···Y binary hydrogen-bonded complexes was undertaken to examine the red- and blue-shifting behavior of three model X-H proton donors interacting with a series of Lewis bases: Y = NH, NCLi, NCH, NCF, CH, BF, CO, N and Ne. Two of these proton donors, FArH and FCH, have blue-shifting tendencies, while the third, FH, has red-shifting tendencies. A perturbation theory model for frequency shifts that was derived many years ago was employed to partition the predicted frequency shift into the sum of two components, one dependent on the second derivative of the interaction energy with respect to X-H displacement and the other dependent on the X-H bond length change in the binary complex.
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