Number Of Halogen Atoms Research Articles

Electronic, optical, phonon, and thermodynamic properties of bismuth oxyhalides for photocatalysis application using density functional theory

Bismuth oxyhalide (BiOX) represents a class of layered materials distinguished by unique physicochemical and optical characteristics. This study delivers an extensive investigation into the properties of BiOX crystals, employing first-principles calculations to analyze the electronic band structure, projected density of states (PDOS), Raman and infrared (IR) spectra, dielectric functions, alongside phonon and thermodynamic properties. The computed electronic band gaps BiOI, BiOBr, BiOCl, and BiOF crystals were determined to be 2.19 eV, 3.05 eV, 3.29 eV, and 3.43 eV, respectively. Furthermore, an analysis of the PDOS for each BiOX type indicates that the valence band maximum (VBM) primarily comprises dominant O 2p and halide X np states, while the conduction band minimum (CBM) predominantly features Bi 6p states. In addition, significant absorption edges for BiOI, BiOBr, BiOCl, and BiOF crystals, oriented along the [100] axis, were observed at wavelengths of 540 nm, 449 nm, 367 nm, and 320 nm, respectively. The Raman spectral analysis revealed a noticeable shift correlating with the increasing number of halogen atoms, with intensity enhancements observed at elevated temperatures. Phonon dispersion studies corroborated the geometric stability of the optimized structures of BiOX crystals. Thermodynamic evaluations suggested that BiOX materials exhibit qualities characteristic of hard materials at higher temperatures while displaying softer material attributes at lower temperatures. In summary, this research substantially enriches the current understanding of bismuth oxyhalides by detailing their structural, electronic, optical, phonon, and thermodynamic properties. The findings presented in this study provide a foundational basis for future advancements in photocatalytic applications and material development.

Optoelectronic and transport properties of Lead-Free halide based Na2AgTlZ6 (Z = Cl, Br, I) double perovskites for energy harvesting applications

The bandgap engineering and deliberate band edge manipulation of perovskites make them potential candidates for the photovoltaic industry. Here we theoretically investigate the structure, density of states, and photovoltaic and thermoelectric characteristics of Na2AgTlZ6 (Z = Cl, Br, I) using WIEN2k code. The incorporation of Br and I at the Cl site caused the increase in lattice constant which leads to the decrease in bulk modulus and Debye temperature. The computed values of Poisson (<0.26) and Pugh (<1.75) ratio verified their brittle nature. The bandgap analysis reveals direct bandgap nature and bandgap value lie in the visible region for parent composition and infrared and far infrared when Cl is replaced with Br and I. The density of state plots uncovers the shifting of energy states in valence and conduction bands towards the Fermi level with the increasing number of electrons in the halogens. The increase in the value of dielectric constant, refractive index, and shifting of peaks towards lower energy value is witnessed with atomic number of halogen atoms. The viability of these compositions for thermoelectric devices is further confirmed when electrical conductivity and Seebeck coefficient dependent Figure of merit and power factor are evaluated in the temperature range of 200–800 K. In addition, the anisotropic nature of studied compositions is explored through the computation of the modulus of elasticity including Young’s modulus, Shear modulus in addition to compressibility, and Poisson’s ratio.

Halogenated 9H-Indeno[1,2-b]Pyrazine-2,3-Dicarbonitrile End Groups Based Asymmetric Non-Fullerene Acceptors for Green Solvent-Processable, Additive-Free, and Stable Organic Solar Cells.

Non-fullerene acceptors (NFAs) significantly enhance photovoltaic performance in organic solar cells (OSCs) using halogenated solvents and additives. However, these solvents are environmentally detrimental and unsuitable for industrial-scale production, and the issue of OSCs' poor long-term stability persists. This report introduces eight asymmetric NFAs (IPCnF-BBO-IC2F, IPCnF-BBO-IC2Cl, IPCnCl-BBO-IC2F, and IPCnCl-BBO-IC2Cl, where n = 1 and 2). These NFAs comprise a 12,13-bis(2-butyloctyl)-3,9-diundecyl-12,13-dihydro-[1,2,5]thiadiazolo[3,4-e]thieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-g]thieno[2',3':4,5]thieno-[3,2-b]indole (BBO) core. One end of the core attaches to a mono- or di-halogenated 9H-indeno[1,2-b]pyrazine-2,3-dicarbonitrile (IPC) end group (IPC1F, IPC1Cl, IPC2F, or IPC2Cl), while the other end connects to a 2-(5,6-dihalo-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile (IC) end group (IC2F or IC2Cl). The optical and electronic properties of these NFAs can be finely tuned by controlling the number of halogen atoms. Crucially, these NFAs demonstrate excellent compatibility with PM6 even in o-xylene, facilitating the production of additive-free OSCs. The di-halogenated IPC-based NFAs outperform their mono-halogenated counterparts in photovoltaic performance within OSCs. Remarkably, the di-halogenated IPC-based NFAs maintain 94‒98% of their initial PCEs over 2000 h in air without encapsulation, indicating superior long-term device stability. These findings imply that the integration of di-halogenated IPCs in asymmetric NFA design offers a promising route to efficient, stable OSCs manufactured through environmentally friendly processes.

Lead-free halide double perovskites Rb2InSbX6 (X = F, Cl, Br, I): A first-principles study of structural and optoelectrical properties

First-principles calculation employing PBE and HSE06 hybrid functionals have been used to investigated the structural optoelectrical properties of lead-free halide double perovskite Rb2InSbX6 (X = F, Cl, Br, and I). The optical bandgaps are 2.48 eV for Rb2InSbF6, 1.18 eV for Rb2InSbCl6, 0.60 eV for Rb2InSbBr6, and 0.23 eV for Rb2InSbI6, which are all direct bandgap semiconductors. Electronic structure calculations reveal that the valence band is made up of the In-5 s and X-p orbitals, whereas conduction band is mostly made up of hybridization between the Sb-5p and X-p orbitals. According to optical properties, these four compounds have strong optical absorption in multi regions. When the number of halogen atoms increased, the absorption spectra shift from the ultraviolet region to the visible region. According to the examination of various optical parameters, Rb2InSbBr6 and Rb2InSbI6 exhibit greater light absorption than Rb2InSbF6 and Rb2InSbCl6 in the visible light range, making them suitable candidates for testing the high-power conversion efficiency and lead-free nature of solar cells.

Quantitative structure activity relationship (QSAR) modeling study of some novel thiazolidine 4-one derivatives as potent anti-tubercular agents

This study aims to develop a QSAR model for Antitubercular activity. The quantitative structure-activity relationship (QSAR) approach predicted the thiazolidine-4-ones derivative’s Antitubercular activity. For the QSAR study, 53 molecules with Antitubercular activity on H37Rv were collected from the literature. Compound structures were drawn by ACD/Labs ChemSketch. The energy minimization of the 2D structure was done using the MM2 force field in Chem3D pro. PaDEL Descriptor software was used to construct the molecular descriptors. QSARINS software was used in this work to develop the 2D QSAR model. A series of thiazolidine 4-one with MIC data were taken from the literature to develop the QSAR model. These compounds were split into a training set (43 compounds) and a test set (10 compounds). The PaDEL software calculated 2300 descriptors for this series of thiazolidine 4-one derivatives. The best predictive Model 4, which has R 2 of 0.9092, R 2adj of 0.8950 and LOF parameter of 0.0289 identify a preferred fit. The QSAR study resulted in a stable, predictive, and robust model representing the original dataset. In the QSAR equation, the molecular descriptor of MLFER_S, GATSe2, Shal, and EstateVSA 6 positively correlated with Antitubercular activity. While the SpMAD_Dzs 6 is negatively correlated with Antitubercular activity. The high polarizability, Electronegativities, Surface area contributions and number of Halogen atoms in the thiazolidine 4-one derivatives will increase the Antitubercular activity.

LAY SULARININ İON-NӘQLETMӘ ÜSULU İLӘ RADİOAKTİV STRONSİUMDAN TӘMİZLӘNMӘSİ

The proposed method is based on ion transport. As a result of research, it was determined that dibenzo-18- crown-6 forms a complex compound by being located between the radioactive strontium ion and the macrocyclic ring. The complex compound formed by crown ether with strontium on the surface of the chloroform layer breaks down due to contact with hydrochloric acid and turns into strontium cation and dibenzo-18-crown-6 compound. The Sr+2 ion released from the decomposition remains in the hydrochloric acid layer. It was determined that as the number of halogen atoms in the molecule of the solvent included in the composition of the liquid membrane increases, the ion transport capacity of the membrane increases. The mechanism of its action is due to the fact that the halogen atoms in the solvent increase the hydrophobicity of the liquid membrane.

Partitioning of Persistent Organic Pollutants between Adipose Tissue and Serum in Human Studies.

Blood is the most widely used matrix for biomonitoring of persistent organic pollutants (POPs). It is assumed that POPs are homogenously distributed within body lipids at steady state; however, the variability underlying the partitioning of POPs between fat compartments is poorly understood. Hence, the objective of this study was to review the state of the science about the relationships of POPs between adipose tissue and serum in humans. We conducted a narrative literature review of human observational studies reporting concentrations of POPs in paired samples of adipose tissue with other lipid-based compartments (e.g., serum lipids). The searches were conducted in SCOPUS and PUBMED. A meta-regression was performed to identify factors responsible for variability. All included studies reported high variability in the partition coefficients of POPs, mainly between adipose tissue and serum. The number of halogen atoms was the physicochemical variable most strongly and positively associated with the partition ratios, whereas body mass index was the main biological factor positively and significantly associated. To conclude, although this study provides a better understanding of partitioning of POPs to refine physiologically based pharmacokinetic and epidemiological models, further research is still needed to determine other key factors involved in the partitioning of POPs.

Semiquantitative Characterization of Bromo-chloro Paraffins and Olefins in the Australian Environment.

A semiquantitative high-resolution mass spectrometry method was developed and applied to assess the occurrence of bromo-/chloro paraffins (BCPs) and olefins (BCOs) in the environment. More than 400 possible BCPs and BCO congener groups were detected in dust, air, and sewage sludge samples collected from Australia. Median chain analytes with the number of halogen atoms <7 (CnHmClxBry, 14 ≤ n ≤ 17, x + y < 7) prevailed in the dust and sludge samples, while short chain analytes (CnHmClxBry, 10 ≤ n ≤ 13, x + y < 7) predominated the air samples. The estimated concentrations of ∑BCPs and ∑BCOs in dust and sludge were approximately 20% that of the chlorinated paraffins (CPs) present, with the median concentrations of 5.4 μg/g (dust) and 0.18 μg/g (sludge) for ∑BCPs and 22 μg/g (in dust) and 0.50 μg/g (sludge) for BCOs. In the air samples, the concentrations of BCPs (0.020 pg/m3) and BCOs (0.032 pg/m3) were 3-4 orders of magnitudes lower than the concentrations of CPs (790 pg/m3). Significant correlations (P < 0.001) were found between the concentration of CPs, BCPs, and BCOs in all the matrices.

In‐Depth Understanding of the Effect of Halogen‐Induced Stable 2D Bismuth‐Based Perovskites for Photocatalytic Hydrogen Evolution Activity

AbstractHalide perovskites are excellent catalysts for photocatalytic hydrogen (H2) evolution; however, their instability in aqueous systems limits their applications. In this study, an alternative system is presented to avoid the ionization of halide perovskites based on ethanol splitting and three Bi‐based halide perovskite nanosheets (Cs3Bi2X9 PNs; X = I, Br, Cl) are prepared for H2 evolution. Small amounts of these halide perovskites possess good stability in ethanol, where the optimal Cs3Bi2I9 PNs exhibit the highest H2 evolution rate of 2157.8 µmol h−1 g−1. In particular, the effects of halogen regulation on the H2 evolution activity are investigated in depth from various perspectives for Cs3Bi2X9. The increased number of halogen atoms reduces the Bi···Bi distance in the octahedral configuration and eliminates the strong localization of electron–hole pairs, which are conducive to photogenerated charge separation and transfer. In addition, the dominant contribution of halogens to the conduction band is enhanced with an increase in the halogen atomic number. This study establishes a novel strategy for studying Bi‐based perovskites for optimizing their photocatalytic properties. Furthermore, it provides a new perspective for developing highly efficient and stable H2 evolution systems for halide perovskites.

Decontamination of chloropicrin (PS) and its analogues using graphene and modified graphene surfaces: a computational study

The growing use of pesticides is a cause of major concern because it poses harm not only to the environment but to human health as well. Chloropicrin (PS) is a volatile organic compound (VOC) used as a fumigant and is hence harmful to the atmosphere and needs to be removed before it can cause any harm. Graphene-based materials have been widely used as decontaminants because of their unique structure and properties. Here we have explored the interaction of not only pristine graphene (PG) but also some of its modified forms using periodic density functional (DF) calculations with dispersion corrections (DFT-D). Several possible modes of adsorption have been explored in each case. The pesticide is only physisorbed on pristine graphene. Doping with boron leads to a further decrease in the adsorption energy, but doping with nitrogen has the opposite effect, leading to a substantial increase in the adsorption energy, but it is still physisorption with no formation of bonds. Doping with BN also leads to negligible adsorption energy. Doping with a stronger n-type dopant, Fe, was also considered, and in this case, there is chemisorption, one C-Cl bond dissociating and the Cl getting attached to the Fe atom. Finally, decoration with a small Fe4 cluster led to the strongest chemisorption, the pesticide getting completely dissociated. We also considered the effect of decreasing number of halogen atoms and change in the halogen on the adsorption on Fe4-decorated graphene.

Sustainability and application of corncob-derived biochar for removal of fluoroquinolones

Biochar-inspired tertiary removal system is beneficial in preventing antibiotic residue discharged from hospital wastewater treatment. Taking advantage of a simple kiln controlled at around 600 °C, we succeeded in carbonizing corncobs to biochar with a surface area of 306 m2/g. Using ciprofloxacin (CFX), ofloxacin (OFX), and delafloxacin (DLX), we demonstrated the performance of the corncob biochar for the sorption removal. The pseudo-second-order rate of DLX was lower than CFX and OFX. The maximum sorption capacity Qmax of 93.9 μg/g for DLX, 399.6 μg/g for CFX, and 306.0 μg/g for OFX were estimated using the Langmuir model. The parameter KL relating to binding strength for DLX is 8 times larger than CFX and OFX. The Qmax could be mainly determined by the pore size distribution of the biochar and the dimensions of FQs considering hydration. Furthermore, we discussed that these results might relate to the number of halogen atoms and functional groups in the fluoroquinolones.

Halogen-driven bandgap opening in graphdiyne for overall photocatalytic water splitting

In this work, we studied the electronic band structure of the halogen (F, Cl, and Br) functionalized graphdiynes (GDYs) by using hybrid density functional theory. The results revealed that the bandgap energies of modified GDYs increase as the number of halogen atoms increases. It is also found that the position of the valence band maximum (VBM) is influenced by the electronegativity of halogen atoms. The higher the electronegativity, the deeper the VBM of the GDYs modified by the same number of halogen atoms. Importantly, our results revealed that the bandgap of GDY could be effectively tuned by mixing types of halogen atoms. The new generated conduction band and valence band edges are properly aligned with the oxidation and reduction potentials of water. Further thermodynamic analysis confirms that some models with mixing types of halogen atoms exhibit higher performance of overall photocatalytic water splitting than non-mixing models. This work provides useful insights for designing efficient photocatalysts that can be used for overall water splitting.

Halogenation of N′-(Arenesulfonyl)-N-[2,6(3,5)-dialkyl-4-oxocyclohexa-2,5-dien-1-ylidene]benzenecarboximidamides and Their Reduction Products

Halogenation of N′-(arenesulfonyl)-N-[2,6(3,5)-dialkyl-4-oxocyclohexa-2,5-dien-1-ylidene]benzenecarboximidamides and their reduction products gave derivatives containing up to four halogen atoms. The degree of halogenation can be controlled by variation of the reaction conditions only in the reactions with 2,6(3,5)dimethyl derivatives. The maximum number of halogen atoms were introduced into 2,6(3,5)-dimethyl- and 3,5-diisopropyl-substituted substrates. The presence of bulky tert-butyl groups in the quinoid ring significantly reduced the degree of halogenation, and halogen molecule added to only one C=C double bond of the quinoid ring. The axial orientation of alkyl substituents in the cyclohexene products suggests syn addition of halogens to the C=C double bond of the quinoid ring.

Halogen-Induced Controllable Cyclizations as Diverse Heterocycle Synthetic Strategy.

In organic synthesis, due to their high electrophilicity and leaving group properties, halogens play pivotal roles in the activation and structural derivations of organic compounds. Recently, cyclizations induced by halogen groups that allow the production of diverse targets and the structural reorganization of organic molecules have attracted significant attention from synthetic chemists. Electrophilic halogen atoms activate unsaturated and saturated hydrocarbon moieties by generating halonium intermediates, followed by the attack of carbon-containing, nitrogen-containing, oxygen-containing, and sulfur-containing nucleophiles to give highly functionalized carbocycles and heterocycles. New transformations of halogenated organic molecules that can control the formation and stereoselectivity of the products, according to the difference in the size and number of halogen atoms, have recently been discovered. These unique cyclizations may possibly be used as efficient synthetic strategies with future advances. In this review, innovative reactions controlled by halogen groups are discussed as a new concept in the field of organic synthesis.

Halogen bonding interactions in the XC5H4N···YCF3 (X = CH3, H, Cl, CN, NO2; Y= Cl, Br, I) complexes.

The noncovalent interactions between the σ-hole region outside the halogen atom and the nitrogen atom of pyridine and its para-substituted derivatives are the focus of this work. Based on the analyses of the electrostatic potentials, YCF3 (Y = Cl, Br, I) act as halogen bond donors, XC5H4N (X = CH3, H, Cl, CN, NO2) act as halogen bond acceptors, and the binary halogen-bonded complexes XC5H4N···YCF3 have been designed and investigated by B3LYP-D3/aug-cc-pVDZ calculations together with the aug-cc-pVDZ-PP basis set for iodine. When the halogen bond acceptor remains unchanged, the interactions between C5H5N and YCF3 (Y = Cl, Br, I) increase with the order of Y = Cl, Br, and I. When the halogen donor ICF3 is fixed, the halogen bonding interactions decrease along the sequence of X = CH3, H, Cl, CN, NO2. Therefore, the halogen bond of the CH3C5H4N···ICF3 complex is the strongest. The interactions between Lewis acid YCF3 (Y = Cl, Br, I) and pyridine and para-substituted pyridine are closed-shell and noncovalent interactions. On the one hand, when the halogen bond acceptor XC5H4N is fixed, with the increase of halogen atomic number, the strength of halogen bond increases; on the other hand, when the halogen bond donor ICF3 is fixed, as the electron-withdrawing ability of the electron-withdrawing group (X) increases, the halogen bond gradually weakens.

Probing the halogen bond donation ability of multivalent At-center in AtXn (X = Cl, Br, I; n = 1, 3, 5)⋯H2O/H2S complexes

The theoretical calculations on a direct comparison of hypervalent halogen bonds and conventional halogen bonds have been carried out at the MP2/aug-cc-pVTZ-(PP) level, in which multivalent At center acts as Lewis acid to form a collinear and non-coplanar halogen bond with H2O/H2S. This series of complexes is defined as hypervalent halogen bonds complexes, while the halogen bond complex formed by peripheral substituents X and H2O/H2S is defined as a conventional one. The results show that the strength of the hypervalent halogen bonding interaction increases with the increase in the number of halogen atoms added. Moreover, the interaction energy and the topological analysis etc. demonstrate that the multivalent At center exhibits the strongest halogen bond donation ability compared to the traditional halogen atoms.

Kinetic Study of the Nitrolysis of Haloadamantanes

The kinetics of nitrolysis of haloadamantanes containing halogen atoms in the bridging and bridgehead positions with fuming nitric acid have been studied. The effective nitrolysis constants of eight haloadamantane derivatives have been determined. The reaction is described by pseudo-first-order kinetic equation, and the reactivity decreases as the number of halogen atoms in the substrate molecule increases. Haloadamantanes with less electronegative halogens show higher reactivity.

Hexaarylbutadiene: A Versatile Scaffold with Tunable Redox Properties towards Organic Near-Infrared Electrochromic Material.

When the 1,1,4,4-tetraanilinobutadiene skeleton is attached with two halogenated aryl units at the 2,3-positions, they undergo facile two-electron oxidation to give stable dicationic dyes which exhibit a near-infrared (NIR) absorption whereas the neutral dienes show only pale color. Therefore, a distinct electrochromic response with an absorption change in the NIR region is achieved, which is attracting considerable recent attention from the viewpoint of bioimaging. Herein, we demonstrate that the redox potentials of the 1,1,4,4-tetraanilinobutadiene can be precisely controlled by the donating properties of the amino group on the aniline unit as well as the number of halogen atoms on the aryl units at 2,3-positions on the butadiene. In contrast, the NIR absorption bands mainly depend on the number of halogen atoms irrespective to the donating properties of aniline unit. Thus, the hexaarylbutadiene skeleton is proven to be a versatile scaffold to develop less-explored organic NIR electrochromic materials, whose redox and spectroscopic properties can be finely tuned by modifying/attaching the proper substituents.

Evaluation of the Influence of Halogenation on the Binding of Bisphenol A to the Estrogen-Related Receptor γ.

Halogenation of organic compounds is one the most important transformations in chemical synthesis and is used for the production of various industrial products. A variety of halogenated bisphenol analogs have recently been developed and are used as alternatives to bisphenol A (BPA), which is a raw material of polycarbonate that has adverse effects in animals. However, limited information is available on the potential toxicity of the halogenated BPA analogs. In the present study, to assess the latent toxicity of halogenated BPA analogs, we evaluated the binding and transcriptional activities of halogenated BPA analogs to the estrogen-related receptor γ (ERRγ), a nuclear receptor that contributes to the growth of nerves and sexual glands. Fluorinated BPA analogs demonstrated strong ERRγ binding potency, and inverse antagonistic activity, similar to BPA. X-ray crystallography and fragment molecular orbital (FMO) calculation revealed that a fluorine-substituted BPA analog could interact with several amino acid residues of ERRγ-LBD, strengthening the binding affinity of the analogs. The ERRγ binding affinity and transcriptional activity of the halogenated BPAs decreased with the increase in the size and number of halogen atom(s). The IC50 values, determined by the competitive binding assay, correlated well with the binding energy obtained from the docking calculation, suggesting that the docking calculation could correctly estimate the ERRγ binding potency of the BPA analogs. These results confirmed that ERRγ has a ligand binding pocket that fits very well to BPA. Furthermore, this study showed that the binding affinity of the BPA analogs can be predicted by the docking calculation, indicating the importance of the calculation method in the risk assessment of halogenated compounds.

Comparative performance of TiO2-rGO photocatalyst in the degradation of dichloroacetic and perfluorooctanoic acids

Halogenated organic compounds are frequently characterized by their bioaccumulative nature, and long­term effects on human health. Their low biodegradability and their difficult removal by conventional technologies lead to their undesirable persistence in the environment. Titanium dioxide and reduced graphene oxide TiO2-rGO composites have shown promising results with enhanced photocatalytic degradation rates compared to bare TiO2 in the degradation of a good number of persistent pollutants. In this context, this work deepens on the influence of the type and number of halogen substitution on the photocatalytic degradation of halogenated organic compounds (HOCs). For the experimental analysis two HOCs, dichloroacetic acid (DCA) and perfluorooctanoic acid (PFOA), have been selected as both molecules differ in the type of halogen atoms, chlorine and fluorine, the number of halogen atoms, and in the length of the alkyl chain. The results showed that TiO2-rGO catalysts achieved a similar kinetic performance for the removal of the primary contaminant in terms of its degradation rate. Besides, TiO2-rGO composite successfully induced the release of all chlorine atoms from the DCA molecule, achieving its total mineralization. However, PFOA defluorination and mineralization rates were remarkably lower than its degradation rate. Although both contaminants released two halogen atoms step-by-step for the degradation of each molecule, PFOA dehalogenation was slowed down due to the generation of secondary products that retain fluorine. Therefore, we conclude that the composite photocatalysts showed a similar performance in terms of degradation rate of the primary contaminant independent on the length of the alkyl chain and on the number of halogen atoms, however, the mineralization and dehalogenation rates were strongly dependent on the number of halogen substituents and the length of the alkyl chain.