Photocatalytic hydrogen production via water splitting is a sustainable and promising green technology. Producing clean hydrogen fuel using sunlight will significantly benefit the environment. TiO2 photocatalysts can split water into H2 and O2 under sunlight. However, the wide band gap of TiO2 ( 3.2 eV) limits its activity to UV-light, making it inactive under visible light. Doping with cations has been shown to enhance visible-light absorption and affect the photocatalytic properties of TiO2. Despite extensive research, there is still no clear explanation for how different cations influence its activity under solar irradiation. In this study, the non-defective anatase (001) surface was modeled using finite, neutral, stoichiometric cluster models derived from bulk anatase. Doped models were created by substituting one Ti atom with a cation, and their positions were optimized for minimum energy. Calculations were carried out using Density Functional Theory (DFT) with the B3LYP hybrid functional and the 6-31G(d) basis set. All dopants were found to reduce the TiO2 band gap, improving visible-light activity. Additionally, metal doping positively influenced water decomposition. Water showed a tendency to remain dissociated in clusters doped with +4 and +5 valence cations, indicating enhanced catalytic potential. Among these, the Ta5+-doped cluster exhibited the highest reaction energy, suggesting that future studies should focus on the reaction energetics of +5 valence doped systems to better understand their role in photocatalytic efficiency.

The incorporation of amino substituents at the peri-positions of perylene monoimides (PMIs) produces elusive push-pull systems with absorption and emission properties in the UV-vis and Near-IR regions. We describe a survey of different direct amination methods for the one-step synthesis of a series of 9-alkylamino and 9-arylamino PMIs. The first method tested is direct amination in neat amines and succesfull only for pyrrolidine. The second method uses the PCC/AgNO3 oxidant system, and high yields are obtained with pyrrolidine. The third method employs KMnO4/AgNO3 as a stronger oxidant system. Pyrrolidine and piperidine are favorable amines for this method, and even diamino PMIs can be obtained. The fourth method uses a Cu(II) salt as a catalyst, and cyclic amines afford products in high yields. The final method is the anion-mediated direct amination and provides the most suitable method for a variety of cyclic, alkyl, and aryl amines to give 9-alkylamino and 9-arylamino PMIs in high yields. In this method, TBAF or TBAOH is used as the anion source, and our detailed spectroscopic and synthetic studies reveal that, as a result of single-electron transfer from the anion, PMIs can generate radical anions and participate in a radical mechanism in amination.

In this study, two metal-free organic dyes (B1 and B3) with a D–π–A architecture were synthesized and investigated for dye-sensitized solar cell (DSSC) applications. The dyes featured triphenylamine as electron donor, an imidazole π-bridge, and 1,10-phenanthroline as anchoring unit. Notably, B3 incorporated multiple anchoring units, enabling direct comparison with single-anchor B1. Structural characterization was conducted using FT-IR, NMR, mass spectrometry, UV-Vis, and electrochemical measurements. Density functional theory (DFT) calculations indicated that B3 has a smaller HOMO–LUMO gap and greater charge localization at the anchor, implying more efficient electron injection. Device testing confirmed B3’s superior performance, as DSSCs with B3 reached 0.61

In this study, organic dyes (B1 and B3) with a D–π–A architecture were synthesized for use in dye-sensitized solar cells (DSSCs). The molecules were designed with triphenylamine as the electron donor, an imidazole bridge, and 1,10-phenanthroline as an anchoring unit to facilitate efficient electron transfer to the semiconductor (TiO₂) surface. The multi-anchor structure of B3 was intended to enhance power conversion efficiency (PCE) by enabling more efficient electron injection from the donor group to the semiconductor. Structural characterization of the dyes was performed using FT-IR, NMR, mass spectrometry, UV-Vis spectroscopy, and electrochemical measurements. Theoretical calculations were performed using the density functional theory (DFT) method with the 6-31G(d)/LANL2DZ basis set. Theoretical analysis revealed that lower band gap energy would facilitate electron transfer between the HOMO and LUMO levels, thus potentially increasing PCE values. The B3 compound exhibited a lower band gap energy compared to B1. The DSSC device incorporating the multi-anchor B3 dye achieved higher power conversion efficiency than the device containing the single-anchor B1 dye. Photovoltaic measurements showed that the DSSC device incorporating B3 achieved a PCE of 0.61%, whereas the device with B1 reached a PCE of 0.28%. The obtained results showed that B3 compound possesses promising structural properties for photovoltaic applications.

The extensive use of antibiotics has raised growing environmental concerns about their potential threat to aquatic ecosystems. Cefradine (CFD) is one of the first-generation beta-lactam cephalosporin antibiotics. In this study, the mechanism and kinetics of the OH radical degradation reaction of cefradine and its protonated form were investigated. Quantum chemical modeling of all reaction paths was performed with Density Functional Theory (DFT) at the B3LYP/6-31g(d,p)//6-311+g(d,p) level. The main reaction path with the highest calculated branching ratio among the reaction paths was the OH addition path to the carbonyl group of beta-lactam. The temperature effect for the reactions was also calculated. The calculated second-order rate constant, 4.82x109 M- 1s- 1, is consistent with the literature data. The possible subsequent mechanism and the potential for direct photolysis of the reaction intermediates were also investigated. Furthermore, the toxicities of the CFD and reaction products were calculated and some of the reaction products are developmental toxicants.

The synthesis, characterization, and electronic properties of 4-((7-methoxyquinolin-4-yl)oxy), 4-(quinolin-2-ylthio), and 4-((7-(trifluoromethyl)quinolin-4-yl)thio) peripherally substituted oxo-titanium phthalocyanines are described for the first time. The structures of the compounds were determined by UV-Vis, FTIR, 1H NMR, and MALDI-TOF mass spectrometry. Electronic spectra and molecular and electronic properties of compounds were calculated by Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) methods. Solvent effects on the electronic, geometric, and reactivity properties of the compounds were also investigated. Global and local reactivity indices and Molecular Electrostatic Potential surfaces of compounds were calculated. The reactivities and electronic structures of molecules vary depending on the solvent and substituents. It has been found that the synthesized compounds can be used for different purposes such as dye-sensitized solar cells and photodynamic therapy applications.

The presence of pharmaceuticals such as the antibiotic cephalexin in aqueous environments increases public health concerns due to their adverse biological effects and antibiotic resistance. It may be promising to remove these compounds from the aquatic environment through degradation reactions that convert them into non-toxic products. For this purpose, Density Functional Theory (DFT) molecular orbital calculations were performed to investigate the kinetics and mechanism of the degradation reaction of cephalexin with the hydroxyl (OH) radical. Reaction rate constants and branching ratios for 11 different reaction paths were calculated in the temperature range of 200 to 400 K. The total rate constant was calculated as 7.05 × 109 M−1 s−1 and is in good agreement with the experimental value. According to the kinetic and thermodynamic results, it can be concluded that the hydroxyl radical preferentially attacks the beta-lactam ring. The effect of water on the reaction mechanism was investigated in both implicit and explicit solvation models. Explicitly added water molecules affect the degradation reaction kinetic so that the results become compatible with the experimental ones. Ecotoxicity and bioaccumulation calculations on cephalexin and its degradation products show that some of its degradation products are harmful.

Water contamination is one of the most critical environmental issues, necessitating the development of effective wastewater treatment methods. The utilization of TiO2 photocatalysts for pollutant removal in wastewater has gained significant attention. This study aims to explore the photocatalytic properties of TiO2 modified through the introduction of different metal dopants, thus altering its electronic structure. Using the density functional theory (DFT) method, we examined the photocatalytic properties of TiO2 clusters doped with metals carrying charges of +3, +4, and +5. Our findings indicate that the incorporation of these metals led to reduced energy and increased stability for the majority of TiO2 clusters. The calculated UV-vis absorption results revealed that the wavelengths of Model B were extended further in the metal cation-doped TiO2 clusters compared to Model A. Our DFT calculations demonstrated that the photocatalytic activity of the TiO2 structure was enhanced upon doping with metals of +3, +4, and +5 valence.

In recent years cancer has become a global problem and burden to the health system. Photodynamic therapy (PDT) and sonodynamic therapy (SDT) are promising alternatives for cancer treatment. It is very important to use phthalocyanines as sensitizers in such treatments. In this study, a new type of Zn-phthalocyanine compound (2) peripherally substituted with 4-Hydroxy-7-methoxyquinoline was synthesized and characterized, and its photodynamic and sono-photodynamic efficiencies were examined. Additionally, the electronic and spectroscopic properties of the compounds were calculated theoretically using Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) methods. The effect of the solvent on the reactivity of the compounds was examined by the Conductive-Like Polarizable Continuum Model (CPCM). The results have indicated that singlet oxygen quantum yield has increased in the sono-photochemical study (ΦΔ=0.98) compare to the photodynamic study (ΦΔ=0.70). Experimental and theoretical study results show that the reactivity of the new ligand increases with Zn metal.

Ampicillin (AMP) is a penicillin-class beta-lactam antibiotic widely used to treat infections caused by bacteria. Therefore, due to its widespread use, this antibiotic is found in wastewater, and it contains long-term risks such as toxicity to all living organisms. In this study, the degradation reaction of ampicillin with hydroxyl radical was investigated by the density functional theory (DFT) method. All the calculations were performed with B3LYP functional at 6-31G(d,p) basis set. The thermodynamic energy values and reaction rates of all possible reaction paths were calculated. The addition of the hydroxyl radical to the carbonyl group of the beta-lactam ring is thermodynamically the most probable reaction path. The calculated overall reaction rate constant is 1.36 × 1011 M−1 s−1. To determine the effect of temperature on the reaction rate, rate constants were calculated for all reaction paths at five different temperatures. The subsequent reaction kinetics of the most preferred primary route was also examined, and the toxicity values of the intermediates were estimated. The acute toxicity of AMP and its degradation product were calculated using the Ecological Structure Activity Relationships (ECOSAR) software. The degradation product was found to be more toxic than AMP.

Degradation reactions of micropollutants such as antibiotics with OH radicals are very important in terms of environmental pollution. Therefore, in this study, the degradation kinetic mechanism of 6-aminopenicillanic acid (6-APA) with OH radical was investigated by density functional theory (DFT) methods. For the calculations, different functionals such as B3LYP, MPW1PW91, and M06-2X were used with a 6-31 g(d,p) basis set. The aquatic effect on the reaction mechanism was investigated by conductor-like polarizable continuum model (CPCM). For the degradation kinetics in aqueous media, the addition of explicit water molecules was also calculated. Subsequent reaction mechanism for the most probable reaction product was briefly discussed. Among the functionals used, B3LYP results were consistent with the experimental results. Calculated kinetic parameters indicated that the OH-addition path was more dominant than the H-abstraction paths. With the increase of explicit water molecules in the models, the energy required for the formation of transition state complexes decreased. The overall rate constant is calculated as 2.28 × 1011 M−1 s−1 at 298 K for the titled reaction.

Phthalocyanines (Pcs) are an important group of substances with interesting chemical and physical properties with many different application areas. The use of Pc compounds in photodynamic therapy (PDT), especially in the treatment of cancer, has gained great importance in recent years. In this study, the spectral and electronic properties of new PDT active anticancer non-peripheral tetrakis [2-mercaptoquinoline]phthalocyanine and metal complexes were examined by using Density Functional Theory (DFT). Their properties were computed in DMSO and water phases. The UV absorption spectrum study results show that the main transition responsible for the Q band of the molecular spectrum is from [Formula: see text] to [Formula: see text]. The presence of the heavier atom in the Pc cavity has the effect of enhancing the fluorescence quantum yield. In addition, photochemical singlet oxygen production of newly synthesized phthalocyanine and metal complexes was also investigated. The calculated spectral (UV, IR, NMR) and singlet oxygen yield results were compared with the experimental ones and they were in good agreement.

Sulfonamides (SAs) are an important group of antibiotics. Due to their widespread use, they have been found as micropollutants in different ecosystems. The presence of SAs in the environment is a serious threat to human health. Degradation reactions of SAs with OH radicals are important for their removal from the environment. This study aims to predict the reaction mechanisms of selected six SAs with center dot OH radical by the DFT method. For this purpose conceptual DFT has been applied to SA + OH degradation reactions to find possible reaction paths. The electronic properties, global and local descriptors of SAs have been calculated. Global and local descriptors are good parameters to predict the reaction mechanisms. Local descriptors were used to find the most suitable sites for the attack of the hydroxyl radical and to predict all possible products. The proposed products and mechanism of the reactions are in agreement with experimental data.

These days, the world is facing the threat of pandemic Coronavirus Disease 2019 (COVID-19). Although a vaccine has been found to combat the pandemic, it is essential to find drugs for an effective treatment method against this disease as soon as possible. In this study, electronic and thermodynamic properties, molecular electrostatic potential (MEP) analysis, and frontier molecular orbitals (FMOs) of nine different covid drugs were studied with Density Functional Theory (DFT). In addition, the relationship between the electronic structures of these drugs and their biological effectiveness was examined. All parameters were computed at the B3LYP/6-311++g(d,p) level. The Solvent effect was evaluated using conductor-like polarizable continuum model (CPCM) as the solvation model. It was observed that electrophilic indexes were important to understand the efficiencies of these drugs in COVID-19 disease. Paxlovid, hydroxyquinone, and nitazoxanide were found as the most thermodynamically stable molecules. Thermodynamic parameters also demonstrated that these drugs were more stable in the aqueous media. Global descriptors and the reactivity of these drugs were found to be related. Nitazoxanide molecule exhibited the highest dipole moment. The high dipole moments of drugs can cause hydrophilic interactions that increase their effectiveness in an aqueous solution.

Sulfonamides are one of the most important classes of chemicals found in the aquatic environment as a pollutant due to excessive consumption. The DFT- B3LYP method with the basis set 6-311++G (d,p) was employed to calculate various quantum chemical descriptors of sulfonamide molecules. A quantitative structure activity relationship (QSAR) study was performed for the toxicity value LD50 of sulfonamides with their quantum chemical descriptors by multi linear regression. The QSAR models were validated by internally and externally. The best multilinear equation with correlation coefficient, R and the cross-validation leave-one-out correlation coefficient, Q2 values were 0.9528 ,0.8556 respectively The results show that the QSAR models have both favourable estimation stability and good prediction power.

In this study, phosphonium salt-bearing polynorbornenes were synthesized using five different aromatic side chains (triphenylphosphonium, trifluorophenyl phosphonium, trichlorophenyl phosphonium, tri(p-tolyl)phosphonium, and cyclohexyldiphenyl phosphonium) via ring-opening metathesis polymerization (ROMP). The biological activities of these polymers were determined by their minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Escherichia coli and Staphylococcus aureus, and additionally, cytotoxicity studies on red blood cells were performed to report on their hemolytic activities (HC50). All of the synthesized polymers were found to be more active toward S. aureus than E. coli, and among them, tri(p-tolyl)phosphonium-and cyclohexyldiphenyl phosphonium-bearing homopolymers were found to be the most active against S. aureus (MIC: 2 mu g mL(-1)) under the Mueller Hinton Broth (MHB) medium; however, the polymers were also found to be hemolytic (HC50 <= 8 mu g mL(-1)). The electron densities of the monomers were calculated via computational studies to investigate the structure-property relationship for the biocidal activities of polymers. Furthermore, the morphological changes of the bacteria in the presence of the polymers were investigated by scanning electron microscopy (SEM) and zeta potential studies using dynamic light scattering (DLS) to speculate about the killing mechanism of the biocidal polymers. In the second part of this study, a series of copolymers were also synthesized to obtain selective copolymers, i.e., nontoxic and biocidal polymers. Using proper monomer compositions in copolymer series, the selectivity against S. aureus versus human red blood cells was determined to be 128.

In this paper the reaction kinetics of dimethyl phosphoramidate with hydroxyl radical was investigated with Density Functional Theory. Geometry optimization and energy calculations of the reactants, the pre-reactive complexes, the transition states and the products were performed at the B3LYP/6-31G(d) basis set. The water effect was computed by using CPCM as the solvation model. Rate constants of all the possible reaction paths were calculated via Transition State Theory. The branching ratio for each of the reaction paths was calculated. The most probable reaction path was found the hydrogen abstraction from methyl group of dimethyl phosphoramidate.

The presence of organophosphorus compounds (OPs) in the environmental counterparts has become an important problem because of their toxicity. In this study, the photocatalytic degradation reactions of the three OPs with hydroxyl radical were investigated by both experimental and quantum chemical methods. Photocatalytic degradation kinetics of the examined organophosphorus compounds were investigated under UV-A irradiation using TiO2 as the photocatalyst. The effects of the initial concentrations on the degradation rate have been examined. There was an observable loss of OPs in the presence of TiO2 photocatalyst under UV-A at 0.2 g TiO2 per 100 mL. The quantum chemical calculations have been carried out by the density functional theory (DFT) at B3LYP/6-31g(d) level. The reaction pathways were modelled to find the most probable mechanism for OPs with the OH radical and to determine the primary intermediates. The rate constants of the eight reaction paths were calculated by the transition state theory. Conductor-like polarizable continuum model (CPCM) was used as the solvation model with the intention of understanding the water effect. The theoretical results were in agreement with experimental ones.

In this paper the reaction kinetics of dimethyl phosphoramidate with hydroxyl radical was investigated with Density Functional Theory. Geometry optimization and energy calculations of the reactants, the pre-reactive complexes, the transition states and the products were performed at the B3LYP/6-31G(d) basis set. The water effect was computed by using CPCM as the solvation model. Rate constants of all the possible reaction paths were calculated via Transition State Theory. The branching ratio for each of the reaction paths was calculated. The most probable reaction path was found the hydrogen abstraction from methyl group of dimethyl phosphoramidate.