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Electrostatic correlation free energy (ECF) is the basis for modeling the thermodynamic behavior of polyelectrolyte solutions. In the past, it has mainly been estimated using the Edwards approximation, valid for infinite chains. Here, we show that the leading contribution due to finite molecular size is of order , regardless of the fractal dimension , where is proportional to molecular weight. This contribution is a local effect, originating from the missing correlations among connected charges near chain ends. In contrast, the contribution from the long-wavelength or infrared regime is weaker, of order ln . Closed-form expressions for the free energy are provided for polyelectrolytes exhibiting either coil- or rod-like statistics, in the absence or presence of small ions. The consequence of the end effect is demonstrated by evaluating the phase diagram, surface tension, and molecular weight-driven partitioning.
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http://dx.doi.org/10.1039/d5sm00633c | DOI Listing |
Chemistry
September 2025
Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Würzburg, 97074, Germany.
Photosensitization has emerged as a versatile tool to facilitate access to excited states under mild conditions, allowing for efficient and selective photochemical transformations. Herein, we report a very simple molecule, coronene bisimide (CBI), as a potent visible-light photosensitizer featuring a high extinction coefficient with a broadband absorption spanning from ultraviolet to green region of the visible spectrum, along with a long-lived triplet state generated via efficient intersystem crossing (ISC). Utilizing the triplet-triplet energy transfer (TTEnT) strategy, CBI catalyzes diverse reactions under green light irradiation.
View Article and Find Full Text PDFChem Commun (Camb)
September 2025
School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 611731, China.
This study pioneers the use of organic nitrate C(NH)NO as an electrolyte additive in lithium metal batteries (LMBs). C(NH)NO can effectively construct a high-quality solid electrolyte interphase (SEI) on the lithium metal anode, thereby enabling dendrite-free and uniform spherical lithium (Li) deposition.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2025
Department of Chemistry and Sustainable Technology, University of Eastern Finland, Joensuu Campus, Yliopistokatu 7, FI-80100, Joensuu, Finland.
Accurate thermodynamic calculations for aluminum alkyls require proper treatment of low-frequency vibrations poorly described by the harmonic approximation (HA). Here, we present a systematic investigation of hindered rotation and out-of-plane bending in aluminum trichloride (ATC) and its methyl derivatives, employing advanced computational methods to perform anharmonic entropy corrections, such as torsional eigenvalue summation (TES), the extended two-dimensional torsion method (E2DT), the multi-structural approximation with torsional anharmonicity (MS-T), and Fourier grid Hamiltonian (FGH). Our results reveal distinct structure-dependent behaviors: monomers exhibit near-free methyl rotations where the HA overestimates entropy by 20-30 J K mol, while dimers show more hindered rotations adequately described by the HA around room temperature.
View Article and Find Full Text PDFNanoscale Horiz
September 2025
Departamento de Ciencias del Ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Av. Libertador Bernardo O'Higgins 3363, Estación Central, Santiago, 9170022, Chile.
The functional electronic and spectro-electrochemical properties of two structural pyridinium isomers, Py_Down-BF and Py_Up-BF, were studied at the single-molecule level using the STM-BJ technique. These isomers differ in the position of the redox-active pyridinium core. The aim was to identify the role of core's position in promoting reversible switching between electromers (redox isomers) in solution and at the gold-pyridinium-gold junction circuit.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2025
Institute of Modern Optics and Center of Single-Molecule Science, Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Nankai University, Tianjin, 300350, China.
Radical coupling reactions have been widely used in the synthesis of complex organic molecules, materials science, and drug research. However, restricted conditions or special catalysts are required to overcome the energy barrier and trigger the coupling reaction efficiently. In this study, we provide experimental evidence that the C─N radical coupling reactions can be significantly accelerated by an oriented external electric field (OEEF) under synchronous UV irradiation without a catalyst.
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