ABSTRACT
Our recent study [M. Li et al.Phys. Chem. Chem. Phys., 2023, 25, 2595-2605] unveiled that the impact of an external electric field on molecular acidity and aromaticity for benzoic acid is directional, which can be understood using changes in frontier orbitals and partial charges. However, it is unclear if the effect will disappear when substituting groups are present and whether new patterns of changes will show up. In this work, as a continuation of our efforts to appreciate the impact of external electric fields on physiochemical properties, we find that the directionality effect is still in place for substituted benzoic acid derivatives and that there exists the additivity effect with respect to the number of substituent groups, regardless of the direction of the applied field and the type of substituting groups. We confirm the findings using electron-donating and electron-accepting groups with the electric field applied either parallelly or perpendicularly to the carboxyl group along the benzene ring. The directionality and additivity effects uncovered from this work should enrich the body of our knowledge about the impact of external electric fields on physiochemical properties and could be applicable to other systems and properties as well.
ABSTRACT
The impact of external fields on the molecular structure and reactivity properties has been of considerable interest in the recent literature. Benzoic acid as one of the most widely used compounds in medicinal and materials sciences is known for its dual propensity in aromaticity and acidity. In this work, we systematically investigate the impact of a uniform external electric field on these properties. We apply density functional theory, conceptual density functional theory, and an information-theoretic approach to appreciate the change pattern of aromaticity and acidity properties in external fields with different strengths. Our results show that they possess different change patterns under external fields, which can be satisfactorily rationalized by variations in reactivity descriptors and partial charges. The surprising yet novel results from this study should enrich the body of our knowledge about the impact of external fields for different kinds of electronic properties and provide guidance and foundation for future studies of this phenomenon in other molecular systems.
Subject(s)
Benzoic Acid , Electricity , Density Functional Theory , Molecular StructureABSTRACT
Small atomic clusters with exotic stability, bonding, aromaticity, and reactivity properties can be made use of for various purposes. In this work, we revisit the trapping of noble gas atoms (He-Kr) by the triatomic H3+ and Li3+ species by using some analytical tools from density functional theory, conceptual density functional theory, and the information-theoretic approach. Our results showcase that though similar in geometry, H3+ and Li3+ exhibit markedly different behavior in bonding, aromaticity, and reactivity properties after the addition of noble gas atoms. Moreover, the exchange-correlation interaction and steric effect are key energy components in stabilizing the clusters. This study also finds that the origin of the molecular stability of these species is due to the spatial delocalization of the electron density distribution. Our work provides an additional arsenal towards a better understanding of small atomic clusters capturing noble gases.
ABSTRACT
Assembling cellulose nanocrystals (CNCs) can induce photonic emission. It is free of photobleaching and aggregation-induced quenching, which has great potential in the application of information security. However, the emission suffers a low emission quantum yield (EQY), and the assembly mediate (solvents) can affect the assembly or the emission. Herein, we established a strategy of nanoscale assembly to integrate emission enhancement methods and improve the assembly induced emission. Via controlling the CNC assembly in the nanoscale space of metal-organic frameworks (MOFs), the EQY of CNC array primarily increased by 50 %. When carbon nanodots were further incorporated in MOF, their plasmonic resonance could enhance the emission coupling rate and offset the loss in emission intensity from the extinction of MOF particles, leading to a 6.9-time increase in EQY (to 64.84 %). Such a high EQY from two emission enhancement mechanisms make this nanomaterial able to hide and present photonic information effectively.
