DFT and TD-DFT Studies of 1,3,5-Tris (Dipheny1amino) Benzene Derivatives Based Hole Transport Materials: Application for Perovskite Solar Cells

The current study examined a series of 1,3,5-tris (diphenylamino) benzene derivatives used as hole transport materials in perovskite solar cells (HTM1-HTM9). DFT and TD/DFT with the B3LYP/6-311G basis set used for all calculations. The ground state geometry, frontier molecular orbital (FMO), photoelectric properties and reorganization energies and the absorption spectra were investigated. The energy levels of HOMO and LUMO orbitals were calculated for HTM1-HTM9, compared to all of the compounds under investigation and the spiro-OMeTAD, HTM 8 has the lowest HOMO energy level, indicating a favourable overlap with the MAPbI3 perovskite active layer.

Ring Contraction Reactions of a Non-Benzenoid Aromatic Cation and a Neutral Homoaromatic System into Benzene Derivatives

Aromaticity is one of the most intriguing concepts in organic chemistry. Simple and extended benzenoid aromatic systems have been very well established in undergraduate textbooks, and there are also mentions of non-benzenoid aromatic structures such as cyclopropenium, cyclopentadienide and cycloheptatrienylium (tropylium) ions. However, the structural relationship and the comparison of stabilization energy of such aromatic ions to benzene ring have been rarely studied and remained an underexplored area of advanced organic chemistry research. To contribute some insights into this topic, we focused on the chemical transformation, namely a ring contraction reaction, of the tropylium ion to benzene ring in this work. With an approach combining computational studies with experimental reactions, we also aim to turn this transformation into a synthetically useful tool. Indeed, this work led to the development of a new synthetic protocol, which involved an oxidative ring-contraction of tropylium ion, to formally introduce the phenyl ring onto a range of organic structures. Furthermore, the homoaromatic cycloheptatrienyl precursors of tropylium salts used in these reactions can also be rearranged to valuable benzhydryl or benzyl halides, enriching the synthetic utility of this ring-contraction protocol.

Oxidative Degradation of Hazardous Benzene Derivatives by Ferrate(VI): Effect of Initial pH, Molar Ratio and Temperature

Two of the most hazardous benzene derivatives (HBD) that have polluted the aquatic environment are bromobenzene and chlorobenzene. Ferrate can degrade various pollutants quickly and efficiently without producing harmful byproducts. This study aims to determine the ability of ferrate to degrade harmful contaminants such as bromobenzene and chlorobenzene. A series of batch experiments were carried out, including for the molar ratio, initial pH solution, and temperature. The study was conducted at an initial pH of 3.6 to 9.6, a molar ratio of 2 to 8 and a temperature of 15 to 55 °C. The study will also examine the differences in functional groups in these pollutants. As a result of the experiments, the optimum conditions to oxidize HBD in a batch reactor was found to have an initial pH of 7.0, a molar ratio of 8, and a temperature of 45 °C, with a 10 min reaction time. Ferrate has a degradation ability against chlorobenzene greater than bromobenzene. The functional cluster in pollutants also significantly affects the degradation ability of ferrate. The results of the degradation experiment showed that ferrate(VI) could effectively oxidize hazardous benzene derivatives in a solution.

2,2′-(1,4-Phenylene)bis(7-nitro-1H-benzimidazole 3-oxide)

Bis(benzimidazol-2-yl-3-oxide)benzene derivatives have potential applications as energetic or photoactive materials. By using a two-step one-pot approach employing microwave heating as a tool, 2,2′-(1,4-phenylene)bis(7-nitro-1H-benzimidazole 3-oxide) (1) has been prepared in 94% yield. In the first step an SNAr reaction is performed using p-xylylenediamine as the central building block. Without isolating the intermediate, a base-mediated cyclization reaction follows in the second step. The product was isolated in analytically pure form by means of a pH-controlled precipitation.

1,2,3-Tri(9-anthryl)benzene. Photophysical Properties and Solid State Intermolecular Interactions of Radially Arranged, Congested Aromatic π-Planes

We report the Negishi coupling based synthesis of 1,2,3-tri(9-anthryl)benzene derivatives, containing three radially arranged anthracenes in a π-cluster. In the crystalline state of the unsubstituted derivative, intermolecular π-π and CH-π interactions between the anthracene units drive the formation of a two-dimensional packing structure. Owing to though-space π-conjugation between anthracene units, the substances have unique electronic properties. The excited state dynamic behavior occurring between the three radially arranged anthracene moieties, such as exciton localization/delocalization, was elucidated by means of transient absorption measurements and quantum chemical calculations. Interestingly, even though the three anthracenes are closely oriented with a ca. 3.0 Å distances between their C-9 positions, exciton localization on two anthracene units is energetically favorable because of the flexible nature of the radially arranged aromatic rings.