Journal of Chemical Sciences最新文献

Self-driving or autonomous labs are platforms that integrate artificial intelligence (AI)/machine learning (ML), robotics and high-throughput experiments, and are capable of designing, synthesizing, testing and optimizing materials for specific purposes with minimal human intervention. Crucial components are algorithms and methods that are capable of generating new materials with desired properties. A recent study by Zeni et al. has reported a material generative model, MatterGen that is fine-tuned to propose new materials conditioned on user-specific mechanical, electronic and magnetic properties.

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Fully autonomous chemistry laboratories bring together advanced generative AI algorithms, robotic systems and high-throughput experiments that can computationally design, and experimentally synthesize and characterize molecules/materials. In this news story, we discuss the importance of methods such as recently proposed MatterGen in making self-driving laboratories a reality.

An eco-friendly method for synthesizing naphthalene diazonium salts and azo dyes has been developed, offering a sustainable alternative to the traditional techniques requiring strong acids and extensive cooling. Aryldiazonium ions derived from nitroanilines are effective for vivid color labeling and precursors for durable azo dyes. In this method, naphthylamines (1-naphthylamine, 4-nitro-1-naphthylamine, and 2,4-dinitro-1-naphthylamine) undergo diazotization using tert-butyl nitrite and p-toluenesulfonic acid in an organic solvent at room temperature. The products obtained are bench-stable for several months and have been utilized as intermediates for azo dye formation by coupling with 2-naphthol at room temperature. A complete spectroscopic technique using 1D and 2D NMR with the mass spectrometric characterization of the dyes reveals that they exist as azo-hydrazone tautomers. The percentage hydrazone tautomer was calculated using the ¹⁵N chemical shift, ¹J_NH coupling constant, as well as the predicted ¹³C chemical shift. The result obtained shows that the synthesized dyes are predominantly present in hydrazone form (71%, 90%, and 94% for compounds 1c, 2c, and 3c, respectively). The electrospray ionization mass spectrometry analysis confirmed the mass of the dyes at m/z 298, 343, and 388, respectively. The environment-friendly and thermostable diazonium salts have been synthesized and also successfully employed as intermediates in synthesizing azo dyes with precise structural elucidation.

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An eco-friendly synthesis of naphthalene diazonium salts and azo dyes was developed using tert-butyl nitrite and p-toluenesulfonic acid. 1D and 2D NMR spectroscopy revealed dominant azo-hydrazone tautomerism, with hydrazone content reaching up to 94%. This method offers sustainable alternatives for stable dye synthesis with precise structural elucidation.

This study presents a novel approach for synthesizing various regio-selective 3,5-disubstituted isoxazoles using inexpensive CuI catalysis. Moderate to good yields of the target compounds were achieved through this method. Based on the experimental results and literature insights, a plausible mechanism involving two consecutive Cu-catalytic cycles, Sonogashira coupling, and intramolecular cyclization was proposed. Notably, opposite regio-selectivity was observed between products obtained from uncatalyzed and CuI-catalyzed reactions. The outcomes of this CuI-catalyzed one-pot protocol represent an improvement over previous methods, offering a promising avenue for diverse isoxazole derivative synthesis. The proposed process involves homogeneous CuI-promoted one-pot three-component regio-selective synthesis of 3,5-disubstituted isoxazoles, with key in situ α,β-unsaturated ynone intermediates crucial for subsequent reactions. This approach streamlines synthesis, allowing simultaneous assembly of multiple chemical components in a single reaction vessel, while minimizing the need for complex steps and costly reagents. Overall, this strategy holds promise for rapid and economical production of diverse 3,5-disubstituted isoxazoles, with potential applications in medicinal chemistry and materials science.

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Apart from tri-iso-amyl phosphate (TiAP), which has been used in fast reactor fuel reprocessing, several studies have focused on various derivatives of amyl phosphates for their potential application in the extraction of U and Pu. For effective decontamination of heavy metals, it is crucial that the uptake of fission products be minimized by target ligands. In this study, we explore the primary interaction, i.e., the molecular level interaction of Zr [in the form of Zr(NO₃)₄], a troublesome fission product, with four amyl phosphates using computational chemistry techniques. The four ligands studied are tri-sec-amyl-phosphate (TsAP), tris (2-methylbutyl) phosphate (T2MBP), tri-iso-amyl-phosphate (TiAP), and tri-n-amyl-phosphate (TAP). Calculations indicate that, for the single-step 1:2 complex formation, all four ligands exhibit almost the same binding affinity towards zirconium nitrate, with a marginally higher propensity for TsAP and TAP. The stepwise formation of 1:2 complex was also studied starting from Zr(NO₃)₄.2H₂O, in which the formation of the 1:2 complex was attributed via the respective 1:1 complexes, i.e., Zr(NO₃)₄·H₂O·L. Here the 1:1 complexes of TsAP, TiAP and TAP ligands were found to be more stable compared to the T2MBP complex and the higher stability is attributed to the presence of intra-molecular hydrogen bond present between the H atom of water and the O atom of the nitrate. Interestingly, it was observed that the zirconium nitrate moiety is highly sensitive to the external ligand environment, as evident from the very high strain or deformation energy of the metal nitrate upon complexation.

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Zirconium Amyl Phosphate Complexes: The interaction of zirconium nitrate [Zr(NO₃)₄] with four amyl phosphates (TsAP, T2MBP, TiAP, and TAP) indicates a higher affinity for the TsAP and TAP ligands. The study also highlights the sensitivity of zirconium nitrate to external ligand environments, as evidenced by significant deformation energy upon complexation.

The ever-increasing global energy demand has necessitated alternate sources of energy. Photoelectrochemical water splitting proved to be a viable method of green hydrogen production. In the present study, four different one-dimensional titanium dioxide nanotube arrays (TNAs) were fabricated by varying the time duration of the second anodization. The highly ordered TNAs proved to be potential photoanodes for photoelectrochemical water splitting, for production of hydrogen. The fabricated TNAs were confirmed as stable anatase crystal structures using X-ray diffraction and Raman spectroscopy analysis. The TNAs showed an increase in length with an increase in anodization time. The morphological studies revealed the formation of the one-dimensional tube-like morphology of TNAs with lengths varying from 1.41 μm to 6.35 μm. The increased length and one-dimensional nanotube formation implied an increased number of active sites and an increased surface-to-volume ratio. The observed increase in photocurrent may be attributed to increased electrode–electrolyte interfacial area, where charge and mass transport occured. The band-gap of the TNAs showed a minimal progressive decrease with an increase in anodization time. The oxidation states of the constituent elements were confirmed using X-ray photoelectron spectroscopy. Contact angle measurement indicated a transition from slight hydrophobicity to slight hydrophilicity with an increase in the anodization time of the TNAs. Electrochemical studies of TNAs exhibited increased photo-response with an increase in anodization time. The influence of anodization time on the characteristics of TNAs is explored in this study.

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TiO₂ Nanotube Arrays (TNAs) were synthesized by two – step anodization method, by varying second anodization time. The TNAs were tested for their efficacy as photo-anode, following exhaustive characterization techniques. The activity of the potential photoanodes for PEC water splitting was analyzed using LSV, CA, EIS and Tafel plots

Microhydration of neutral and anionic nitromethane molecules was investigated up to (n =10) water molecules using dispersion-corrected density functional B2PLYPD with aug-cc-pVDZ basis sets. The calculated interaction energies of both anion and neutral nitromethane–water clusters were extrapolated to the complete basis set (CBS) limit. It was observed that the water molecules interact with the methyl group of the nitromethane in the case of a neutral molecule, whereas in anionic nitromethane hydration, water molecules build a hydrogen bond network strongly around the nitro group of the nitromethane. The SAPT analysis and MED critical point calculations have revealed that the anionic nitromethane–water cluster is more stable as compared to the neutral one. Further, the SAPT analysis showed that an increase in stability in case of the interaction in an anionic nitromethane–water complex is because of a higher attractive contribution from the electrostatic and dispersion components. The vertical detachment energy (VDE) and electron affinity (EA) values of nitromethane were also calculated, and the VDE values were found to be in good agreement with the experimental values.

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Anionic Nitromethane-(H₂O)_n clusters investigated using Dispersion Corrected Density Functional Theory and compared with neutral counterparts. The calculated VDE values show good agreement with Experimental values.

The proposed research aims to investigate the structure and lowest excitation properties of GG-CC and GC-CG (G, guanine; C, cytosine) peptide nucleic acid (PNA) dimers, incorporating different amino acids such as serine, aspartic acid, and histidine using the density functional theory (DFT) and time-dependent density functional theory (TDDFT) methods. The structures under consideration have been optimized at the Becke’s three-parameter hybrid density functional (B3) with correlation function of Lee, Yang and Parr (LYP)/6-31G* level of theory. The study involves calculating the backbone torsions and backbone-base linker torsions, correlating them with experimental data. The computed excitation energy for the GG-CC PNA system is compared with the natural GG-CC DNA system. The lowest excitation properties, such as excitation energy, wavelength, and oscillator strength, reveal their dependency on both the stacking arrangement and the molecular environment, irrespective of whether the PNA is modified or unmodified. Additionally, a highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) analyses were conducted. This study is intended to serve as a foundational tool for understanding the molecular behaviour of PNAs under light absorption, potentially leading to further exploitation in photo-related applications.

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This article explores the application of conceptual density functional theory (CDFT) and information-theoretic approach (ITA) to various chemical phenomena, demonstrating their predictive power in diverse molecular systems. IT descriptors have been employed to investigate conformational stability, molecular acidity, aromaticity, and electrophilicity/nucleophilicity, revealing strong correlations between information-theoretic measures and experimental observations. Moreover, CDFT-based QSAR and QSPR models have shown significant predictive capabilities in pharmacological toxicity and physicochemical properties, such as partition coefficient and enthalpy of vaporization. The integration of CDFT and IT descriptors has provided deeper insights into reactivity trends in pericyclic reactions, allowing for the classification of mechanisms based on electrophilicity indices. Additionally, periodic trends in CDFT and IT descriptors have been examined, reaffirming the fundamental chemical principles. The review article underscores the robustness of IT and CDFT methodologies in capturing electronic structure variations and predicting the chemical behavior of molecules. The integration of these descriptors offers a comprehensive approach to understanding chemical reactivity, stability, and molecular interactions, paving the way for future advancements in theoretical and computational chemistry.

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The applications of Conceptual Density Functional Theory (CDFT) and the Information-Theoretic Approach (ITA) have been widely used in predicting the toxicity, activity, and reactivity of chemical systems. Moreover, Quantitative Structure–Activity Relationship (QSAR) studies are conducted using CDFT and ITA descriptors through regression equations.

A recent study by Liam Longo and co-workers at the Earth-Life Science Institute, published in Angewandte Chemie, reports the discovery of an ancient helix-hairpin-helix protein motif capable of functioning in both left- and right-handed forms, thus challenging the concept that biomolecular interactions are strictly dependent on homochirality. This rather rare “ambidextrous” property suggests that such motifs may be molecular relics from a pre-LUCA era when mirror-image life forms coexisted, and offers new insights into the origins and evolution of molecular asymmetry seen in living matter.

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The ‘helix-hairpin-helix’ motif allows the binding of a simple peptide to both DNA and its mirror image. Credit: Liam M S Longo.