Effects of pnictogen and chalcogen bonds on the aromaticities of carbazole-like and dibenzofuran-like molecular skeletons: Cambridge Crystallographic Data Centre (CCDC) Study

Abstract

a Parameterization scheme used in geometry-based aromaticity index Harmonic Oscillator Model for Heterocycles with π-electrons and n-electron delocalization was extended to cover certain pnictogen (group 15) and chalcogen (group 16) elements, for example, phosphorus, arsenic, selenium, and tellurium. Thus, assessment of aromaticities of dibenzofuran-like and carbazole-like molecular skeletons including the aforementioned pnictogens and chalcogens besides nitrogen, oxygen, and sulfur was made possible. Our results have shown that aromaticity of five-membered and six-membered rings in the considered skeletons can be independently treated from each other. Arsenic, phosphorus, and sulfur are the most suitable heteroatoms in the considered molecular skeletons to be used in designing π-conjugated functional materials, because they have potentially smaller band gap due to the presence of the less aromatic flanking benzenes. Differences in aromaticities of two flanking benzenes of the molecular skeletons including pnictogens are more pronounced than those of molecular skeletons including chalcogens.

Structural Characterization, Theoretical Investigation and Hirshfeld Surface Analysis of 2,6-(E,E)-bis((thiophene-2-yl)methylene)cyclohexanone

“…Also, The HOMO-LUMO energy gap (ΔE) represents the lowest energy electronic transition which mainly belongs to π-π* excitation [33]. HOMO-LUMO band gap increases linearly with increasing aromaticity [34]. Thiophene ring is more aromatic structure.…”

Organophosphorus Compounds in Organic Electronics

“…As outlined in Scheme , the phosphole core is often incorporated into larger aromatic systems with one or two annulated (hetero‐)aromatic ring systems. The retaining of aromaticity at the annulated (hetero‐)aryls leads to a further decrease of aromaticity at the phosphole ring, altering the optical properties . The formation of these larger planar π‐conjugated systems enhances desirable properties, such as a reduced HOMO–LUMO splitting (E g ) and red‐shifted absorption and emission maxima.…”

Investigations of the hydrogen bond in the crystals of tropolone and thiotropolone via car‐parrinello and path integral molecular dynamics

“…Keto‐enol tautomerism (KET) is very important in carbonyl chemistry (carbonyl specialty reactions) and also in several areas of biochemistry . In recent years, much attention has been paid to the experimental and theoretical studies of KET and proton transfer in enol tautomer of phenols, aldehydes, β‐diketones, and hydrazones . As can be seen, among the publications on KET, the dominate works that also deal with the subject of the resonance‐assisted hydrogen bonds (RAHBs) .…”

“…[43] In recent years, much attention has been paid to the experimental and theoretical studies of KET and proton transfer in enol tautomer of phenols, [44] aldehydes, [45][46][47][48][49][50] β-diketones, [45][46][47][48][49][50][51][52][53][54][55] and hydrazones. [56][57][58] As can be seen, among the publications on KET, [43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58] the dominate works that also deal with the subject of the resonance-assisted hydrogen bonds (RAHBs). [48,56,57] It can therefore be concluded that these phenomena (KET and RAHB) are closely related and often occur together.…”