Structure, stability and electronic properties of one-dimensional tetrathia- and tetraselena[8]circulene-based materials: a comparative DFT study

Abstract

Computations reveal how the electronic and optical properties can be controlled in nanostructures.

Unraveling the Aromatic Rule of Cyclic Superatomic Molecules in π-Conjugated Compounds

“…When substituting the basic benzene unit in Cn with thiophene and furfuran rings, heterocyclic [n]circulenes, which have been widely synthesized and used as promising materials, are obtained. 8,9 Using the same theoretical model, thiophenebased cyclic compounds Sn/Sn' are demonstrated to feature similar aromaticity like Cn, as shown in Despite the different basic structural units, an accordant superatomic bonding motif with ◊ O and ◊ F in SP 2 hybridization is summarized for Cn, Sn, and On based on the superatomic Lewis structures and NICS(1) contour planes. To better understand the chemical bonding in these unified superatomic Lewis structures, adaptive natural density partitioning (AdNDP) analysis is performed for C5, C5′, C7, and S8 (Figure 4).…”

“…When substituting the basic benzene unit in C n with thiophene and furfuran rings, heterocyclic [ n ]­circulenes, which have been widely synthesized and used as promising materials, are obtained. , Using the same theoretical model, thiophene-based cyclic compounds S n / S n ’ are demonstrated to feature similar aromaticity like C n , as shown in Figure . S n ( n = 2–7) /S n ’ ( n = 5–7) are treated as ◊ O n ‑2 ◊ F 2 with 4 n + 2 π electrons.…”

“…In past decades, π-conjugated compounds with high molecular symmetry have attracted considerable attention, − among which the representative [ n ]­helicenes and [ n ]­circulenes were widely synthesized and characterized, such as coronene ([6]­circulene) and tetrathio[8]­circulene . In particular, circulenes can be coupled through post-transformation into one- or two-dimensional (1/2D) materials that have demonstrated useful semiconducting or semimetallic properties. , For example, some hetero­[ n ]­circulenes are employed as promising materials in the field of nanoelectronics for manufacturing organic light-emitting diodes and field-effect transistors. ,− In 2006, a planar π-conjugated molecule, octathio[8]­circulene (C 16 S 8 ), with near D 8h symmetry was synthesized by Nenajdenko et al It is the first fully heterocyclic circulene, popularly called “sulflower”, showing special structural characteristics that prompt a number of efforts to interpret its aromaticity, as well as to specify its research and industrial applications. − …”

Aromaticity of Heterocirculenes

“…Their analysis sheds new light on the differences in physico-chemical properties of various series of heterocirculenes. All types of classifications analyzed in this review are used in practical implementation of heterocirculenes in molecular electronics and in the IR, UV, and NMR spectral interpretations [103][104][105][106][107][108][109]. During the preparation of this paper, a new hybrid aromatic molecule with alternating thiophene and furan rings, called an oxisulflower (with 10-fused rings), and "pure" oxiflower (with 14-furan fused) rings was modeled as a potential structure for synthesizing sulflower (octathia [8]circulene) [110].…”