Quantum Chemical Study Research Articles

Quantum Chemistry Study on Cl-Initiated Reactions of 2-Chloropropane and 2-Methylpropanoyl Halogen (Cl, Br, F): Mechanism, Kinetics, and Atmospheric Implications

Quantum Chemistry Study on Cl-Initiated Reactions of 2-Chloropropane and 2-Methylpropanoyl Halogen (Cl, Br, F): Mechanism, Kinetics, and Atmospheric Implications

Computational Studies of Molybdenum-Containing Metal–Sulfur and Metal–Hydride Clusters

The development of transition metal clusters is an active area of research in inorganic chemistry, as they can be used as catalysts to perform chemically or biologically relevant reactions. Computational chemistry, employing density functional theory (DFT), plays a key role in rationalizing the electronic structure and properties of transition metal clusters. This article reviews recent quantum chemical studies of Mo3S4M clusters (M = Fe, Co, Ni), their CO- or N2-bound variants, and metal–hydride clusters. The ground state of the cluster systems was computed, and properties such as metal–metal bonding, orbital interactions, fluxional behavior of ligands, spectroscopy, and reaction mechanisms were rationalized and compared with available experimental results. Our research findings evidence that computational studies employing quantum chemical methods can guide experimental researchers to develop novel transition metal clusters for potential applications in catalysis.

Affecting Charges and Structures of {Bi6} Architectures by 12‐Electron Transition Metal Fragments

AbstractMolecules based on polyatomic bismuth substructures are currently attracting a lot of attention owing to this heavy and essentially non‐toxic element's uncommon chemical and physical properties, which include unprecedented bonding properties. Hexaatomic {Bi6} substructures that underly more complex cluster structures were recently reported to adopt different structures or exhibit different structural details as a consequence of the charge of the {Bi6} unit. This leads to either crown‐shaped cycles for a nominal Bi66− or differently distorted trigonal prisms for compositions close to Bi62−. It was predicted by quantum chemistry that Bi64− should adopt a distinctly distorted boat‐like shape, yet a corresponding compound has remained elusive. Here, we report a proof of this assumption by the synthesis of [K(crypt‐222)]2[Bi6{Zn(hmds)}2] ⋅ 1.5THF (1), comprising a bimetallic [Bi6{Zn(hmds)}2]2− cluster that fulfills the prediction for the geometric and electronic structure of the missing link (crypt‐222=4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo‐[8.8.8]hexa‐cosane, hmds=hexamethyldisilazanid). A detailed quantum chemical study shows how the nature of Lewis‐acidic transition metal complexes—in particular, 12‐electron fragments—control and fine‐tune the resulting {Bi6} architectures in accordance with the degree of electron‐withdrawal from the polybismuthide core.

Synthesis, spectroscopic characterization techniques of aromatic iminoaniline derived compound, along with the evaluation of its LNO properties using quantum chemistry

In this research work, we synthesized a Schiff base derivative, N,N-dimethyl-4-{[(4-nitrophenyl)imino]-methyl}aniline, denoted as (n1). The molecule (n1) was characterized using spectroscopic analyses, including FT-IR, NMR 1H, and 13C. Our compound (n1) is an unsaturated molecule, consisting of two benzylic rings connected by a methylimine bridge. The resulting system comprises seven alternating π bonds. At both ends of (n1) and in the para position, there are the N(CH3)2 group with a strong electron-donating effect and the NO2 group with a strong electron-accepting effect. The molecular structure of our compound prompted us to evaluate and study its properties in the field of NLO. The assessment of NLO properties is conducted by determining the Egap and employing density functional theory (DFT) quantum chemistry studies. The optical gap of (n1), measured using the Tauc method, is found to be 2.7 eV, serving as a reference value for the choice of the DFT functional in theoretical calculations. Quantum chemistry studies were carried out using Gaussian09 software, and the results were visualized with GaussView05. CAM-B3lyp functional was chosen for theoretical calculations due to its close agreement with experimental values. The studies confirm that (n1) exhibits significant NLO properties. Additionally, NBO (Natural Bond Orbital) analyses provide insight into the mechanism and trajectory of intramolecular charge transfer in (n1).

Evaluating the antidiabetes and antioxidant activities of halogenated Schiff bases derived from 4-(diethylamino)salicylaldehyde: in vitro antidiabetes, antioxidant and computational investigation

Six Schiff bases with general name 5-(diethylamino)-2-(((halophenyl)imino)methyl)phenol (where halo = 4-fluoro (H1), 2-fluoro (H2), 2-bromo (H3), 4-bromo (H4), 4-chloro (H5) and 3-chloro-4-fluoro (H6)) were prepared by the condensation reaction between 4-(diethylamino)salicylaldehyde and suitable halogenated aromatic amines. The six halogenated Schiff bases were elucidated using different spectroscopic techniques and the structure of H3 and H6 were confirmed using single-crystal X-ray crystallography. The bond lengths of C7–N1, C7–C8 and C8–C9 obtained from structural analysis for both compounds depicted their enol-tautomeric characteristic form. The Hirshfeld analysis revealed that H‧‧‧H intermolecular contacts contributed most towards the Hirshfeld surfaces of both H3 (47.6%) and H6 (39.9%). Quantum chemical calculation studies showed that H1 and H2 have the highest and lowest energy band gap (∆E = 3.80 eV for H1 and ∆E = 3.73 eV for H2), depicting H2 and H1 as the most and least chemically reactive respectively among all the compounds. α-Amylase and α-glucosidase assay were used to evaluate the antidiabetes prowess of the synthesized compounds. All the compounds exhibited lower IC50 values than acarbose (reference drug) in α-amylase assay experiments and H5 with lowest IC50 value of 63.54 μM could be suggested to have the highest α-amylase inhibitory potential among the test samples. For α-glucosidase assay, H1–H6 displayed good antidiabetic potential. However, none of the compounds outshined acarbose with H6 having highest α-glucosidase inhibitory potential when compared to others i.e., IC50 of H6 = 60.89 μM and IC50 of acarbose = 51.42 μM. We measured the antioxidant potential of H1–H6 exploring 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and ferric reducing ability power (FRAP) assays. The DPPH as well as NO radical scavenging assay showed that all the compounds exhibited excellent antioxidant results with some of the compounds surpassing catechin (reference drug). Compound H5 with IC50 values of 30.32 mM and 31.73 mM outshined catechin with IC50 values of 31.17 mM and 140.62 mM for DPPH and NO assays respectively. All the compounds fell within the threshold of Lipinski’s Ro5 projecting them as orally bioavailable and less toxic future therapeutics.

Synthesis, Theoretical Gaussian Quantum Chemical Calculations, and Spectroscopic Elucidation of N‐(4‐bromophenyl)‐10H‐phenothiazine‐10‐carboxamide

AbstractPhenothiazine derivative N‐(4‐bromophenyl)‐10H‐phenothiazine‐10‐carboxamide (BPC), a novel compound is selected for the present study based on the reported effectiveness of phenothiazine towards neurodegenerative diseases. Synthesis and characterization of BPC are carried out in the present work. To comprehend the electronic and structural aspects of BPC, quantum chemical studies are performed. Computational aspects using the density functional theory method using B3LYP/6–31 G ++(d,p) as a basis set are studied for the geometry optimization of the molecule. To analyze the reactivity, stability, and intramolecular interactions of the compound frontier orbital molecular analysis, molecular electrostatic potential distribution, and Fukui function are implemented. Calculations have been made to determine the electrophilic and nucleophilic descriptors of the title compounds by Fukui function evaluations on atomic charges. To visualize and quantify the localization of electrons and molecular orbitals in the molecule, electron localization function, localized orbital locator analysis and orbital localization analysis are carried out for a better understanding of chemical bonding. Basin Analysis is used for analysis of the nature of chemical bonds and interactions. To understand bond strengths, hyperconjugation, and reactivity natural bond orbital analysis is performed.

Screening and evaluation of phase change absorbents by molecular polarity index: Experimental and quantum chemical calculation studies

Phase change absorbents have recently received increasing attention due to their potential to reduce the energy penalty of CO2 capture. However, its complex composition makes the prediction of phase separation performance difficult. Phase separation behavior and phase separation rate have been investigated for the amine-aqueous 5.0 M amine blends by experimental and quantum chemical calculations (including MPI, hydrogen bonds and Gibbs free energy). The different phase behaviors upon CO2 absorption were discussed and well explained by the polarity change of components and the reaction products. A defined MPI value of tertiary amines was recommended to predict the immiscible type (MPI > 10.55 Kcal/mol), phase separation type (9.00 Kcal/mol < MPI < 10.08 Kcal/mol), and miscible type (MPI < 6.74 Kcal/mol). The electron density at the critical point of hydrogen bonds and interaction region indicators were employed to visually evaluate the influence of intramolecular and intermolecular hydrogen bonds on phase separation behaviors. The results show that the presence of excessive hydrogen bonds decreased the phase separation capacity. Furthermore, the relationship between the MPI, the Gibbs free energy of the proton transfer process and the phase separation time were explored. The increase of MPI caused by the tertiary amines can enhance the stability of the final product, delay the appearance of the phase separation peak and reach a maximum phase separation time of 230 min. Therefore, this study is significant for the screening and evaluation of efficient phase change absorbents with good potential for industrial applications in CO2 capture.

Quantum chemical study of trimethylindium and trimethylgallium gas-phase reaction pathways in InGaN MOCVD growth

Density functional theory was used to analyze the formation of InGaN from trimethylindium (TMIn) and trimethylgallium (TMGa) by metalorganic chemical vapor deposition in ammonia in terms of the reaction between trimethyl compounds and NH3, as well as the subsequent reactions of the key amino species DMInNH2. The calculation model is established in GAUSSIAN 09, and the results obtained by the calculation model are proved to be reliable by comparing with the previous research results. Reaction pathways were assumed and the Gibbs free energy and activation free energy calculation were conducted at different temperatures. TMIn and TMGa can undergo adduct reactions with the first NH3 molecule at reaction temperatures below 596 K and 465 K, respectively, but they cannot further react with the second NH3 molecule to form additional products. The temperature range for adduct reactions between TMIn and NH3 is wider compared to TMGa and NH3. In the absence of H radicals in the reaction chamber, DMInNH2 does not undergo spontaneous CH3 radical elimination reactions or CH4 elimination reactions. Instead, DMInNH2 is more inclined to undergo dimerization reactions and CH4 elimination reactions with NH3, leading to the formation of subsequent products, In(NH2)3 and dimers. However, in the presence of H radicals in the reaction chamber, H radicals can facilitate the CH3 radical elimination reaction of DMInNH2 and also promote the NH2 radical elimination reaction of In(NH2)3, In(NH2)2 and InNH2, enabling these reactions to occur spontaneously within the studied temperature range. Consequently, the subsequent products of DMInNH2 become indium atoms and dimers.

One-ElectronNO to N2O Pathways via Heme Models and Lewis Acid: Metal Effectsand Differences from the Enzymatic Reaction.

Some pathogens use heme-containing nitric oxide reductases (NORs) to reduce NO to N2O as their defense mechanism to detoxify NO and reduce nitrosative stress. This reduction is also significant in the global N cycle. Our previous experimental work showed that Fe and Co porphyrin NO complexes can couple with external NO to form N2O when activated by the Lewis acid BF3. A key difference from conventional two-electron enzymatic reaction is that one electron is sufficient. However, a complete understanding of the entire reaction pathways and the more favorable reactivity for Fe remains unknown. Here, we present a quantum chemical study to provide such information. Our results confirmed Fe's higher experimental reactivity, showing advantages in all steps of the reaction pathway: easier metal oxidation for NO reduction and N-O cleavage as well as a larger size to expedite the N/O coordination mode transition. The Co system, with a similar product energy as the enzyme, shows potential for further development in catalytic NO coupling. This work also offers the first evidence that this new one-electron NO reduction is both kinetically competitive and thermodynamically more favorable than the native pathway, supporting future initiatives in optimizing NO reduction agents in biology, environment, and industry.

Spectroscopic, quantum chemical and molecular docking studies of N-((anthracen-9-yl) methylene-2-methyl benzenamine): a potent probe to lipid bilayer systems

ABSTRACT A new synthesized Schiff base, N-((anthracen-9-yl) methylene-2-methyl benzenamine) (AMMB), was prepared from o-toluidine and 9-anthracenecarboxaldehyde. The structure of the compound was confirmed by single crystal X-ray diffraction and characterized through various analytical tools such as high resolution mass, 1H and 13C NMR, infrared, UV-vis and elemental composition analysis. The molecular geometries of AMMB were optimized by means of DFT/B3LYP/6311-G++ (d,p) basis set. The optimized geometric parameters of the compound were concordant with the single crystal structure. The optimized structure was utilized in comparison of experimental FT-IR with calculated frequency calculation. TD-DFT analysis was performed to compute the electronic absorption of the compound. SCF-GIAO was employed to compute 1H and 13C NMR, which was consistent with the experimental results. Additionally, NLO, NBO, MEP and global reactivity parameters were also computed using the same level of theory. Hirshfield surface analysis, fingerprint plot and energy frameworks were presented to explore the intermolecular interactions within the crystal. Molecular docking study was carried out to predict the probable binding site of AMMB into lipid bilayers such as DMPC, DPPC, POPC, DLPE, DOPC and POPE. The molecular docking analysis of AMMB showed complex formation with binding affinity energy ranging from −9.3 to −3.4 kcal/mol.

Piperine analogues as dual inhibitors for antibacterial and antiarthritic properties through impact of ligands optimization, docking and water solvation

The prevalence of bacterial diseases poses a significant challenge because of how they can develop resistance to antibiotics and evade the human immune system, highlighting the need for novel therapeutic approaches. Bacterial infection leads to the degradation of bone tissue and the development of arthritis. This study investigates the antibacterial and antirheumatic properties of piperine analogues. Computational analyses, including molecular docking quantum chemical studies and ADMET analysis, are performed to screen out potential inhibitory compounds. A library of 100 ligands is obtained from PubChem and subjected to virtual screening using various filters, including pharmacophore properties, molecular docking, and toxicity prediction, to identify potential candidates. Four compounds, P1-P4, are selected for further investigation using quantum chemical methods. These compounds are subjected to quantum chemical spectroscopic analysis, including UV–visible and IR spectra. The molecular geometries are fully optimized. HOMO and LUMO orbitals including their energies are calculated to estimate intermolecular charge transfer properties Molecular docking results revealed “compound P3 displayed the highest binding affinity to both proteins, with binding energies of 9.0 kcal/mol and 9.8 kcal/mol for FtsZ and Neutrophil collagenase proteins, respectively”. The analysis of 2D and 3D interactions between the selected compounds and both proteins reveals the formation of three important hydrogen bonds between ligand P3 and the FtsZ protein, as well as two hydrogen bonds between P3 and the Neutrophil collagenase protein. Additionally, ligand P4 forms three hydrogen bonds with the Neutrophil collagenase protein. The small energy gap of 3.85 eV between the HOMO and LUMO of the optimized molecule Neutrophil collagenase indicates that the compound is among the category of soft compounds and biologically more active. As new insights, for the first time, we performed a comparative analysis of the energies of the docked and optimized ligands that reveal the docked ligands always possess higher energies which might be considered as energy-penalty during the docking process. This energy penalty is found to be −24, −22, −26 and −32 kcal/mol for FtsZ and −169, −40, −35 and −39 Kcal/mol for Neutrophil collagenase P1-P4, respectively. The orbital energy gap further decreases in solvation with water and increases its chemical reactivity. Under the solvation effect of water as solvent, the quantum computational results indicated enhanced molecular solubility and stability, which are critical factors for bioavailability. The researchers suggested that the combination of increased reactivity and better solubility ensures that the drug performs more effectively in biological environments, making it a more potent inhibitor for bacterial infections and arthritis. The molecular geometries including bond lengths and bond angles of all studied compounds were also influenced in a solvent environment.

Protein Quakes in Redox Metalloenzymes: Clues to Molecular Enzyme Conductivity Triggered by Binding of Small Substrate Molecules.

Multicentre redox metalloproteins undergo conformational changes on electrochemical surfaces, or on enzyme substrate binding. The two-centre copper enzymes, laccase (Type I and TypeII/III Cu) and nitrite reductase (CuNIR) (Type I and Type II Cu) are examples. With some exceptions, these enzymes show no non-turnover voltammetry on Au(111)-surfaces modified by thiol based self-assembled molecular monolayers, but dioxygen or nitrite substrate triggers strong electrocatalytic signals. Scanning tunnelling microscopy also shows high conductivity only when dioxygen or nitrite is present. Atomic force microscopy shows constant CuNIR height but pronounced structural expansion in the electrocatalytic range on nitrite binding. We have recently offered a rationale, based on ab initio quantum chemical studies of water/nitrite substitution in a 740-atom CuNIR fragment. Presently we provide much more detailed structural assignment mapped to single-residue resolution. NO2 --binding induces both a 2 Å Cu-Cu distance increase, and pronounced frontier orbital delocalization strongly facilitating ET between the Cu regions. The conformational changes transmit from the catalytic Type II centre to the electron inlet Type I centre, via the His129-Cys130 ligands, and via Type I-Cys130 or Type I-His129 ending at Type II Asp92. The ET patterns are reflected in different atomic Mulliken charges in the water and nitrite CuNIR fragment.

Quantum–Chemical Study of the Photophysical Behavior of Mesogenic Europium(III) Complexes with β‐Diketones and Lewis Bases

AbstractMetal‐containing liquid crystals such as Ln(III) complexes possess unique structural, liquid‐crystalline (LC), optical, and magnetic properties and represent modern cutting‐edge multifunctional materials. Application of mesogenic Ln(III) complexes is hindered by their nontrivial structure–property relationships. These relationships, in turn, depend on various factors, including insufficiently studied physicochemical processes. Although a proper Ln(III) element and the respective ligand environment are selected prior to synthesis of such complexes, the structural features of the coordination polyhedra, especially upon photoexcitation, are not uniquely defined. Therefore, this work focuses on the development of theoretical approaches to creating multifunctional materials represented by highly luminescent mesogenic Eu(III) complexes with β‐diketones and Lewis bases. The relationships between their structure, the parameters of Voronoi–Dirichlet polyhedra, the luminescence efficiency, and the LC properties were considered. The calculated excited states and intramolecular energy transfer rates were used to determine intramolecular energy transfer channels. The LC behavior of the studied materials was shown to mainly depend on the ligand environment, whereas their optical properties were found to be mostly governed by the coordination polyhedra.

Unexpected Course of Reaction Between (1E,3E)-1,4-Dinitro-1,3-butadiene and N-Methyl Azomethine Ylide—A Comprehensive Experimental and Quantum-Chemical Study

In recent times, interest in the chemistry of conjugated nitrodienes is still significantly increasing. In particular, the application of these compounds as building blocks to obtain heterocycles is a popular object of research. Therefore, in continuation of our research devoted to the topic of conjugated nitrodienes, experimental and quantum-chemical studies of a cycloaddition reaction between (1E,3E)-1,4-dinitro-1,3-butadiene and N-methyl azomethine ylide have been investigated. The computational results present that the tested reaction is realized through a pdr-type polar mechanism. In turn, the experimental study shows that in a course of this cycloaddition, only one reaction product in the form of 1-methyl-3-(trans-2-nitrovinyl)-Δ3-pyrroline is created. The constitution of this compound has been confirmed via spectroscopic methods. Finally, ADME analysis indicated that the synthesized Δ3-pyrroline exhibits biological potential, and it is a good drug candidate according to Lipinski, Veber and Egan rules. Nevertheless, PASS simulation showed that the compound exhibits weak antimicrobial, inhibitory and antagonist properties. Preliminary in silico research shows that although the obtained Δ3-pyrroline is not a good candidate for a drug, the presence of a nitrovinyl moiety in its structure indicates that the compound is an initial basis for further modifications.

Enhancing Aromaticity of Alkenylbenzenes May Decrease Their Metabolic Activation and Reduce Their Potential Cytotoxicity: Lessons Learnt from the Investigation of Myristicin and Elemicin.

Metabolic activation studies of lead compounds are a crucial step in drug development and offer a key consideration during rational drug design. Myristicin (MRS) and elemicin (ELM), natural products belonging to alkenylbenzenes, share the backbone of 1-allyl-3-methoxybenzene. The backbone fuses with a methylenedioxy five-membered ring in MRS, while ELM is connected with two adjacent methoxy groups. ELM displayed powerful ability to induce cytotoxicity in cultured primary hepatocytes relative to MRS. Additionally, ELM exhibited superior efficiency in metabolic activation by CYP3A4, resulting in the formation of reactive metabolites carbonium ion, epoxides, and α,β-unsaturated ketone. Quantum chemical calculation and molecular dynamic studies revealed that the fused methylenedioxy 5-membered ring enhances the aromaticity of MRS, which affects the interaction between the allyl side chain and the heme for metabolic activation by the π-π stacking interaction with the aromatic amino acid residues of the host enzyme.

Innovative 8-hydroxyquinoline derivatives as corrosion inhibitors for mild steel in hydrochloric acid: a quantum chemical and experimental study

ABSTRACT This study explores the inhibitory action of two novel organic compounds, namely diethyl 1-((8hydroxyquinolin-5-yl)methyl)−2,6-dimethyl-4-(p-tolyl)−1,4-dihydropyridine-3,5-dicarboxylate (PR1) and diethyl 1-((8-hydroxyquinoline-5-yl) methyl)−2,6-dimethyl-4-(4-nitrophenyl)−1,4dihydropyridine-3,5-dicarboxylate (PR2), on mild steel (MS) corrosion in 1M HCl. Using a combination of quantum chemical and experimental methodologies, the study evaluates the performance of these inhibitors through electrochemical techniques, including potentiodynamic polarisation (PDP) and electrochemical impedance spectroscopy (EIS), complemented by surface analysis via scanning electron microscopy (SEM) and X-ray electron microscopy (EDX). Key findings reveal that both PR1 and PR2 exhibit a significant rise in protection performance with concentration, reaching an impressive peak of 95.3% at 10−3 M for PR2. The inhibitors demonstrate mixed-type inhibition properties and adhere to the Langmuir adsorption isotherm. Detailed surface analysis confirms the creation of a defensive film on the metal surface, correlating with the observed electrochemical results.

Role of Intermolecular Interactions in Deep Eutectic Solvents for CO2 Capture: Vibrational Spectroscopy and Quantum Chemical Studies.

Recent research and reviews on CO2 capture methods, along with advancements in industry, have highlighted high costs and energy-intensive nature as the primary limitations of conventional direct air capture and storage (DACS) methods. In response to these challenges, deep eutectic solvents (DESs) have emerged as promising absorbents due to their scalability, selectivity, and lower environmental impact compared to other absorbents. However, the molecular origins of their enhanced thermal stability and selectivity for DAC applications have not been explored before. Therefore, the current study focuses on a comprehensive investigation into the molecular interactions within an alkaline DES composed of potassium hydroxide (KOH) and ethylene glycol (EG). Combining Fourier transform infrared (FT-IR) and quantum chemical calculations, the study reports structural changes and intermolecular interactions induced in EG upon addition of KOH and its implications on CO2 capture. Experimental and computational spectroscopic studies confirm the presence of noncovalent interactions (hydrogen bonds) within both EG and the KOH-EG system and point to the aggregation of ions at higher KOH concentrations. Additionally, molecular electrostatic potential (MESP) surface analysis, natural bond orbital (NBO) analysis, quantum theory of atoms-in-molecules (QTAIM) analysis, and reduced density gradient-noncovalent interaction (RDG-NCI) plot analysis elucidate changes in polarizability, charge distribution, hydrogen bond types, noncovalent interactions, and interaction strengths, respectively. Evaluation of explicit and hybrid models assesses their effectiveness in representing intermolecular interactions. This research enhances our understanding of molecular interactions in the KOH-EG system, which are essential for both the absorption and desorption of CO2. The study also aids in predicting and selecting DES components, optimizing their ratios with salts, and fine-tuning the properties of similar solvents and salts for enhanced CO2 capture efficiency.

Advanced AIE Materials for Environmental Monitoring: Selective Sensing of Thorium(IV) in Aquatic Systems.

Thorium (Th) is commonly used in various applications, but its long-term exposure poses health risks, necessitating its detection in aqueous environments. Traditional methods such as inductively coupled plasma mass spectrometry are sensitive but require complex instrumentation. Optical sensors, particularly fluorometry-based methods, are simpler, cost-effective, and selective. However, developing effective aggregation-induced emission (AIE) turn-on sensors for Th(IV) requires water-soluble fluorophores with a low background fluorescence. In the present work, we report a turn-on detection method for Th(IV) based on the AIE of the fluorophore tetra(4-sulfophenyl) ethylene (SuTPE). Th(IV)-induced aggregation of SuTPE and the simultaneous drastic enhancement of the emission property of SuTPE have been utilized for the selective sensing of Th(IV) in 100% aqueous media. The sensing mechanism was explored using ground-state absorption, steady-state and time-resolved emission, FTIR, DLS, SEM, AFM and quantum chemical studies of the SuTPE-Th(IV) complex. The selectivity of the present probe toward Th(IV) ions has been established by studying the interference of several metal ions, including lanthanides and uranyl ions. The LOD for Th(IV) was estimated to be 240 nM (56 ppb). The performance of the probe was demonstrated in tap water and diluted seawater matrixes. This work provides a significant advance for Th(IV) detection in aqueous environments, with implications for environmental monitoring and health safety.

Affecting Charges and Structures of {Bi6} Architectures by 12-Electron Transition Metal Fragments.

Molecules based on polyatomic bismuth substructures are currently attracting a lot of attention owing to this heavy and essentially non-toxic element's uncommon chemical and physical properties, which include unprecedented bonding properties. Hexaatomic {Bi6} substructures that underly more complex cluster structures were recently reported to adopt different structures or exhibit different structural details as a consequence of the charge of the {Bi6} unit. This leads to either crown-shaped cycles for a nominal Bi66- or differently distorted trigonal prisms for compositions close to Bi62-. It was predicted by quantum chemistry that Bi64- should adopt a distinctly distorted boat-like shape, yet a corresponding compound has remained elusive. Here, we report a proof of this assumption by the synthesis and isolation of [K(crypt-222)]2[Bi6{Zn(hmds)}2]∙1.5THF (1), comprising a bimetallic [Bi6{Zn(hmds)}2]2- cluster that fulfils the prediction for the geometric and electronic structure of the missing link (crypt-222 = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo-[8.8.8]hexa-cosane, hmds = hexamethyldisilazanid). A detailed quantum chemical study shows how the nature of Lewis-acidic transition metal complexes - in particular, 12-electron fragments - control and fine-tune the resulting {Bi6} architectures in accordance with the degree of electron-withdrawal from the polybismuthide core.

Quantum-chemical study of atomic X30 trefoil knots with X = {H, He, Li, Be, B, C}*

Quantum-chemical computations were carried out for a series of circumferences (unknots), trefoil and toric trefoil knots of X30 systems, with X with atomic numbers Z = {1-6}. Relaxed structures lead to different configurations, with the striking cases of C30 and B30, with the former leading to a relaxed trefoil knot and the latter relaxing to a Möbius band, both corresponding to energy minima.