Journal of Physical Organic Chemistry最新文献

The present work explored the effect of –OH group substitution (o/p) on the spectral and electrochemical behavior of N-benzylideneaniline. The geometry optimization of unsubstituted and (o/p)-OH-substituted analogs revealed the coplanarity of the molecules. The vibrational spectra of the compounds were computed using density functional theory (DFT) and compared with the experimental data. The observed bands were assigned based on total energy distribution (TED). Predicted electronic absorption spectra from time-dependent density functional theory (TD-DFT) calculation were compared with the UV–visible spectra of the molecules. The analysis of the lowest spin-allowed (singlet-singlet) excited states divulged possible electronic transition. The o-substituted benzylideneaniline possessed the lowest highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) energy gap among the substituted and unsubstituted analogs. The intramolecular contacts were interpreted using natural bond orbital and localized molecular orbital analysis. The –CH=N– linkage was investigated as a bridge for the electron delocalization from the donor to acceptor moieties. The manifestation of a reduction peak in the cyclic voltammetric studies confirmed the electrochemical behavior in the –OH-substituted molecule, which was diffusion-controlled. The discrepancy in the electrochemical property concerning the position of the –OH substituent of the candidate molecules was put forward.

Polymeric hole transport materials (HTMs) have emerged because of their potential to produce dopant-free, efficient, and stable perovskite solar cells (PSCs). Therefore, we engineered 10 novel donor materials (SMH1–SMH10) containing phenanthrocarbazole-based polymeric structures for organic and PSCs. These molecules underwent bridging-core modifications using different spacers, such as furan (N1), pyrrole (N2), benzene (N3), pyrazine (N4), dioxane (N5), isoxazole (N6), isoindole (N7), indolizine (N8), double bond (N9), and pyrimidine (N10), in comparison to reference molecule R. The study examined the structure–property relationship and the impact of these modifications on the optical, photovoltaic, photophysical, and optoelectronic characteristics of the newly designed SMH1–SMH10 series. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations were conducted to analyze frontier molecular orbitals, density of states, reorganization energies, open-circuit voltage, transition density matrix, and charge transfer processes. Results show that the newly designed molecules (SMH1–SMH10) exhibited superior optoelectronics characteristics compared to the R molecule. Among these, SMH4 is the most promising candidate, with a small band gap (2.79 eV), low electron and hole mobility (λ_e 0.0028 eV, λ_h 0.0020 eV), lower binding energy (E_b 0.58 eV), high λ_max values (656.42 nm in gas, 573.34 nm in chlorobenzene), and a high V_oc of 1.30 V. Therefore, this study demonstrated that bridging-core modifications offer a simple and effective strategy for designing desirable characteristics molecules for photovoltaic applications.

Ketene 1,3-oxazoles and their derivatives present intriguing structures for the study of rotational barriers due to their pseudo–double-bond character stemming from resonance in the ketene moiety. A diverse range of compounds featuring this motif underwent quantum-chemical investigation to elucidate the nature of the stereochemical singularity observed in numerous cases. Because rotational barriers in most instances are too high to permit rapid interconversion, the findings are ascribed to thermodynamic rather than kinetic factors in the gas phase and within an implicit polar medium. The stabilities are attributed to internal hydrogen bonding where feasible. However, in cases where this is not possible, chalcogen bonding rather than steric effects governs the stereochemical preferences, particularly when S and Se comprise the heterocycle of these compounds. These findings hold promise for guiding the design of compounds whose properties hinge on stereochemistry and resonant structures, such as dyes.

The relative stabilities of the syn- and anti-conformers of 72 molecules belonging to the XC(W)ZY type, with X, Y = F, Cl, Br and W, Z = O, S, Se, have been computed using the B3LYP/aug-cc-pVDZ approximation. The conformational preferences, represented by the energy differences between the two rotamers, exhibit a systematic trend in relation to both the halogen atoms and the chalcogen atoms. These computational predictions are in agreement with available experimental results. The NBO formalism was employed to assess the influence of both the conjugative and anomeric interactions on the relative energy of the conformers. It has been determined that the conjugative interaction provides a satisfactory explanation for the energy differences between rotamers. In contrast, the anomeric interactions favors the syn-conformation in all cases. The relative stabilities between XC(W)ZY/YC(W)ZX and XC(W)ZY/XC(Z)WY constitutional isomers have also been computed and correlated with the experimental data.

The conversion of CO₂ into valuable chemicals remains a significant challenge for achieving environmental sustainability, primarily due to the stability of the CO₂ molecule. This necessitates the development of efficient and ecofriendly catalysts. In recent years, frustrated Lewis pairs (FLPs) have shown promise for CO₂ utilization. In this study, we introduce α-aminodiboronic acid (DBA), a novel trifunctional aminoboronic acid, as an intramolecular FLP for converting CO₂ into cyclic carbonate and formic acid. Using density functional theory (DFT) calculations, we explored the reaction mechanism and investigated DBA's electronic structure through molecular electrostatic potential surface (MESP) and natural bond orbital (NBO) analyses. Our results reveal that one −B (OH)₂ group induces an unusual state of frustration in the molecule due to charge transfer from the nitrogen atom's lone pair to the π* orbitals, enhancing catalytic performance. The additional −B (OH)₂ group serves as an anchoring site for reactive species. The epoxide activation energy is reduced by approximately 27 kcal/mol compared to the uncatalyzed reaction, and the reduction of CO₂ occurs with a requirement of 26 kcal/mol. The additional −B (OH)₂ plays a crucial role in the catalytic mechanism and minimizes the energies of various structures observed in the reaction path. The reaction energetics align with structural analysis observations, marking this study as the first report on single-molecule trifunctional FLPs for transforming CO₂ into valuable chemicals.