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In charge-transfer complexes, transition from the donor highest occupied molecular orbital (HOMO) to the acceptor lowest unoccupied molecular orbital (LUMO) gives the charge-transfer absorption. However, in tetracyanoquinodimethane (TCNQ) complexes of thienoacenes, comparison of the observed and calculated charge-transfer absorption demonstrates that the HOMO/LUMO transition is absent in the solid state owing to the orbital symmetry, and the first near-infrared band comes from the transition from the donor next HOMO to the TCNQ LUMO. Maps of the oscillator strength in rotated and translated molecular geometries are calculated on the basis of the time-dependent density functional theory, in which the absence of the HOMO/LUMO transition is approximately maintained even in the general molecular geometry.
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http://dx.doi.org/10.1021/acs.jpca.0c08925 | DOI Listing |
Phys Chem Chem Phys
September 2025
School of Chemistry and Chemical Engineering, Key Laboratory of Theoretical Organic Chemistry and Function Molecule of Ministry of Education, Hunan University of Science and Technology, Xiangtan, 411201, P. R. China.
Additive assisted strategies play a crucial role in optimizing the morphology and improving the performance of organic solar cells (OSCs), yet the molecular-level mechanisms remain unclear. Here, we employ molecular dynamics (AIMD) and density functional theory (DFT) to elucidate the influence of typical additives of 1,8-diiodooctane (DIO) and 3,5-dichlorobromobenzene (DCBB) on molecular packing, electronic structures, and charge transport. It can be observed that both additives can enhance the stacking properties of the donor and acceptor materials, yet they have different effects on the local electrostatic environment.
View Article and Find Full Text PDFACS Omega
September 2025
School of Chemical Engineering, Inner Mongolia Key Laboratory of Theoretical and Computational Chemistry Simulation, Inner Mongolia University of Technology, Hohhot 010051, P. R. China.
The incorporation of transitional elements into silicon or germanium-based semiconductor clusters not only notably improves their structural stability but also endows them with unprecedented multifunctionalities. In this work, the structural, vibrational, and electronic properties for copper-doped silicon and germanium cation clusters Cu (X = Si or Ge, = 6-16) are systematically investigated. The ground-state structures are identified using the PBE0 and mPW2PLYP method combined with a global search technique.
View Article and Find Full Text PDFInorg Chem
September 2025
Department of Chemistry and Chemical Engineering, Heze University, Heze, Shandong 274015, China.
Transition metal (TM)-doped silicon clusters represent critical model systems for understanding nanoscale hybridization and stability mechanisms. This study provides a comprehensive analysis of structural evolution, electronic properties, and thermodynamic stability in ruthenium-doped silicon clusters (RuSi̅, = 7-11) through integrated experimental and computational approaches. Anion photoelectron spectroscopy combined with density functional theory (DFT/B3LYP), coupled-cluster theory [CCSD(T)], and bonding analyses (AdNDP, NICS, ACID) reveals charge-state-dependent structural transitions, with full Ru encapsulation emerging at = 10 for anions and = 11 for neutrals.
View Article and Find Full Text PDFJ Photochem Photobiol B
September 2025
College of Science, Northeast Forestry University, Harbin 150040, China. Electronic address:
This study employs a suite of quantum chemical methods to systematically investigate the photoisomerization mechanism and antioxidant activity of resveratrol (Res) and two key derivatives, Azo-Resveratrol (AzoRes) and Dihydro-Resveratrol (dhRes), thereby elucidating the impact of molecular scaffold modification on their structure-activity relationships. Employing density functional theory (DFT), time-dependent DFT (TD-DFT), spin-flip TD-DFT and multistate complete active space second-order perturbation theory (MS-CASPT2), we investigated the geometric configurations, absorption spectra, photoisomerization pathways, and key antioxidant parameters for all three molecules. The results reveal that the substitution of the CC bond with an NN linkage (AzoRes) induces a bathochromic shift in the absorption spectrum, introduces a low-energy n → π* transition, and facilitates a barrierless photoisomerization pathway.
View Article and Find Full Text PDFJ Mol Model
August 2025
School of Chemistry, University of the Punjab, New Campus Lahore-54590, Punjab, Pakistan.
Context: Computational approaches are instrumental in understanding the structural and electronic characteristics of drug metal complexes, thereby facilitating the rational deign of more effective pharmaceutical agents prior to experimental validation. The present work was designed to evaluate the drug-likeness and therapeutic potential, bioavailability, pharmacokinetics, and toxicity characteristics of piroxicam transition metal (Mn, Fe, Co, Ni, and Zn). Additionally, the comprehensive structural, electronic, and solvent-dependent behavior were investigated through theoretical analysis, with particular emphasis geometry optimizations and stabilization effects explored in solvents such as water, ethanol, and DMSO.
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