scholarly journals Energetic and geometric characteristics of the substituents. Part 1. The case of NO2 and NH2 groups in their mono-substituted derivatives of simple benzenoid hydrocarbons

2021 ◽  
Vol 32 (3) ◽  
pp. 915-923
Author(s):  
Paweł A. Wieczorkiewicz ◽  
Halina Szatylowicz ◽  
Tadeusz M. Krygowski
Keyword(s):  
Density Functional Theory ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Atomic Charge ◽  
Benzenoid Hydrocarbons ◽  
Functional Theory ◽  
New Approach ◽  
Polycyclic Aromatic ◽  
Derivatives Of

AbstractSimple polycyclic aromatic hydrocarbons, substituted by strongly electron-donating (NH2) and withdrawing (NO2) groups, are studied employing density functional theory (DFT) calculations. A new approach to a description of the substituent effect, the energy of substituent, E(X), is proposed and evaluated. It is defined as E(X) = E(R-X)−E(R), where R is the unsubstituted system; X = NH2, NO2. Changes in the energy of the substituents, estimated for the benzene analog, Erel(X), allow the energy of the various substituents to be compared. The obtained values are interpreted through correlations with the geometry of the substituent and the substituted system. We show that Erel(X) is strongly dependent on the proximity of the substitution. Values of Erel(X) are also compared with a substituent descriptor based on atomic charge distribution–charge of the substituent active region, cSAR(X). It has been shown that these two descriptors correlate very well (R2 > 0.99); however, only for linear acenes with similar, “benzene-like” proximity. Moreover, relations between Erel(X) and cSAR(X), the geometry of the substituents, and angle at the ipso carbon atom can be explained by the well-established Bent–Walsh rule.

scholarly journals Binding of polycyclic aromatic hydrocarbons and graphene dimers in density functional theory

2010 ◽  
Vol 12 (1) ◽  
pp. 013017 ◽  
Author(s):  
Svetla D Chakarova-Käck ◽  
Aleksandra Vojvodic ◽  
Jesper Kleis ◽  
Per Hyldgaard ◽  
Elsebeth Schröder
Keyword(s):  
Density Functional Theory ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Functional Theory ◽  
Polycyclic Aromatic

Bowl-to-bowl inversion of sumanene derivatives

2012 ◽  
Vol 84 (4) ◽  
pp. 1089-1100 ◽  
Author(s):  
Toru Amaya ◽  
Toshikazu Hirao
Keyword(s):  
Density Functional Theory ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Dft Calculation ◽  
Functional Theory ◽  
Ongoing Research ◽  
Benzene Rings ◽  
Polycyclic Aromatic ◽  
Anion Species

Bowl-to-bowl inversion is one of the characteristic behaviors for some flexible open-end molecular bowls consisting of polycyclic aromatic hydrocarbons with benzene rings fused by imbedded five-membered rings (π bowls). This intriguing dynamics was studied with sumanene, which is the smallest C3v symmetric fragment of fullerenes. In this article, our ongoing research on the bowl-to-bowl inversion of sumanene, its benzylic anion species, hexasubstituted derivatives, mononaphthosumanene, and [CpRu(η6-sumenene)]+ complex is summarized. Estimation based on density functional theory (DFT) calculation is also described.

scholarly journals Assessment of Density Functional Theory in Predicting Interaction Energies Between Water and Polycyclic Aromatic Hydrocarbons: From Water on Benzene to Water on Graphene

2018 ◽  
Author(s):  
Adeayo Ajala ◽  
Vamsee K. Voora ◽  
Narbe Mardirossian ◽  
Filipp Furche ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Interaction Energies ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Polycyclic Aromatic ◽  
Hydrocarbon Molecules

<div> <div> <div> <p>The interaction of water with polycyclic aromatic hydrocarbons, from benzene to graphene, is investigated using various exchange-correlation functionals selected across generalized gradient approximation (GGA), meta-GGA, and hybrid families within the density functional theory (DFT) hierarchy. The accuracy of the different functionals is assessed through comparisons with high-level electronic structure methods, including random phase approximation (RPA), diffusion Monte Carlo (DMC), and coupled-cluster with single, double, and perturbative triple excitations (CCSD(T)). Relatively large variations are found in the interaction energies predicted by different DFT models, with GGA functionals underestimating the interaction strength for configurations with the water oxygen pointing toward the aromatic molecules, and the meta-GGA B97M-rV and hybrid ωB97M-V functionals providing nearly quantitative agreement with CCSD(T) values available for the water-benzene, water-coronene, and water-circumcoronene dimers, which, in turn, are within ∼1 kcal/mol of the corresponding RPA and DMC results. Similar trends among GGA, meta-GGA, and hybrid functionals are observed for the larger polycyclic aromatic hydrocarbon molecules considered in this analysis (up to C216H36). By performing absolutely localized molecular orbital energy decomposition analyses (ALMO-EDA) of the DFT results, it is found that, independently of the number of carbon atoms and exchange-correlation functional, the dominant contributions to the interaction energies between water and polycyclic aromatic hydrocarbon molecules are the electrostatic and dispersion terms while polarization and charge transfer effects are negligibly small. Calculations carried out with GGA and meta-GGA functionals indicate that, as the number of carbon atoms increases, the interaction energies slowly converge to the corresponding values obtained for an infinite graphene sheet. Importantly, water-graphene interaction energies calculated with the B97M-rV functional appear to deviate by more than 1 kcal/mol from the available RPA and DMC values. </p> </div> </div> </div>

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