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Ketene 1,3‐oxazoles and their derivatives present intriguing structures for the study of rotational barriers due to their pseudo–double‐bond character stemming from resonance in the ketene moiety. A diverse range of compounds featuring this motif underwent quantum‐chemical investigation to elucidate the nature of the stereochemical singularity observed in numerous cases. Because rotational barriers in most instances are too high to permit rapid interconversion, the findings are ascribed to thermodynamic rather than kinetic factors in the gas phase and within an implicit polar medium. The stabilities are attributed to internal hydrogen bonding where feasible. However, in cases where this is not possible, chalcogen bonding rather than steric effects governs the stereochemical preferences, particularly when S and Se comprise the heterocycle of these compounds. These findings hold promise for guiding the design of compounds whose properties hinge on stereochemistry and resonant structures, such as dyes. [ABSTRACT FROM AUTHOR]

Spin‐crossover (SCO) effect on octahedral Co(II) centers is much rarer and less known than in the case of Fe(II) complexes, although it is no less promising for the development of fundamental research, sophisticated memories, and sensors. The representative compound [Co(terpy)2]I2 ⋅ 2H2O (terpy=2,2′:6′,2′′‐terpyridine) was synthesized, and its physicochemical properties were studied both experimentally and theoretically. Magnetic experiments revealed a very gradual SCO between a low‐spin state (SCo(II)‐LS=1/2) and a high‐spin state (SCo(II)‐HS=3/2) for the pristine sample and an abrupt SCO with a narrow thermal hysteresis around 130 K for the desolvated sample. Moreover, temperature‐dependent vibrational and electronic spectroscopy were employed to track the evolution of spectroscopic features related to SCO and desolvation processes. Additionally, quantum chemical calculations were utilized to determine the electronic structure, molecular orbitals, and vibrations for different spin states at various temperatures, offering a more comprehensive understanding of the compound's spectroscopic and magnetic behaviors. These extensive investigations provide valuable insights into Co(II)‐based SCO materials and their theoretical underpinnings, paving the way for the application of their thermometric properties. [ABSTRACT FROM AUTHOR]

The transfer‐free character of graphene growth on Silicon Carbide (SiC) makes it compatible with state‐of‐the‐art Si semiconductor technologies for directly fabricating high‐end electronics. Although significant progress has been achieved in epitaxial growth of graphene on SiC recently, the underlying nucleation mechanism remains elusive. Here, we present a theoretical study to elucidate graphene near‐equilibrium nucleation on Si‐terminated hexagonal‐SiC(0001) surface. It is found that the ultra‐large lattice mismatch between SiC(0001) surface and graphene and the highly localized electron distribution on SiC(0001) surface lead to a distinctive nucleation process: (i) Most of the magic carbon clusters on SiC(0001) show only C1 symmetry and are mainly composed of pentagonal rings; (ii) Two possible nucleation pathways are revealed, i.e., longitudinal and circular modes; (iii) Carbon clusters are more stable on flat terraces than near atomic step edges. Based on above findings, a graphene nucleation diagram on SiC(0001) is established and experimentally observed contradictories for graphene growth on SiC(0001) are answered. Our in‐depth understanding on graphene nucleation on SiC(0001) extends nucleation mechanisms of 2D crystals and will benefit high‐quality graphene growth on SiC(0001). [ABSTRACT FROM AUTHOR]

Urea electrosynthesis from co‐electrolysis of NO3− and CO2 (UENC) under ambient conditions is recognized as an appealing approach for effective and sustainable urea production, while it requires high‐efficiency UENC electrocatalysts to promote the C─N coupling and hydrogenation processes. Herein, single‐atom Cu anchored on MoS2 (Cu1‐MoS2) is explored as a highly active and selective UENC catalyst. Theoretical calculations and operando spectroscopic characterizations unveil the synergistic tandem catalysis of Cu1‐MoS2 for the UENC, where Cu single atoms trigger the early C─N coupling, while MoS2‐edges promote the key hydrogenation step of *CO2NH2 to *COOHNH2 for urea generation. Strikingly, Cu1‐MoS2 equipped in a flow cell achieves the excellent UENC performance with a maximum urea‐Faradaic efficiency of 57.02% at −0.6 V and the corresponding urea yield rate of 23.3 mmol h−1 g−1, surpassing nearly all previously reported UENC catalysts. [ABSTRACT FROM AUTHOR]

Flexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics, and organic cathode materials have become contenders for flexible self‐supporting electrodes. However, issues such as easy electrolyte solubility and low intrinsic conductivity contribute to high polarization and rapid capacity decay. Herein, we have designed a flexible self‐supporting cathode based on perylene‐3,4,9,10‐tetracarboxylic dianhydride (PTCDA), interfacial engineering enhanced by polypyrrole (PPy), and carbon nanotubes (CNTs), forming the interconnected and flexible PTCDA/PPy/CNTs using polymerization reaction and vacuum filtration methods, effectively curbing those challenges. When used as the cathode of sodium‐ion batteries, PTCDA/PPy/CNTs exhibit excellent rate capability (105.7 mAh g−1 at 20 C), outstanding cycling stability (79.4% capacity retention at 5 C after 500 cycles), and remarkable wide temperature application capability (86.5 mAh g−1 at −30°C and 115.4 mAh g−1 at 60°C). The sodium storage mechanism was verified to be a reversible oxidation reaction between two Na+ ions and carbonyl groups by density functional theory calculations, in situ infrared Fourier transform infrared spectroscopy, and in situ Raman spectroscopy. Surprisingly, the pouch cells based on PTCDA/PPy/CNTs exhibit good mechanical flexibility in various mechanical states. This work inspires more rational designs of flexible and self‐supporting organic cathodes, promoting the development of high‐performance and wide‐temperature adaptable wearable electronic devices. [ABSTRACT FROM AUTHOR]

A ladder‐type rigid‐coplanar polymer with highly ordered molecular arrangement has been designed via a covalent cycloconjugation conformational strategy. Benefitting from the extended π‐electron delocalization in the highly aromatic ladder‐type polymeric backbone, the prepared polymer exhibits fast intra‐chain charge transport along the polymeric chain, realizing extraordinary proton‐storage capability in aqueous proton batteries.Affordable and safe aqueous proton batteries (APBs) with unique "Grotthuss mechanism," are very significant for advancing carbon neutrality initiatives. While organic polymers offer a robust and adaptable framework that is well‐suited for APB electrodes, the limited proton‐storage redox capacity has constrained their broader application. Herein, a ladder‐type polymer (PNMZ) has been designed via a covalent cycloconjugation conformational strategy that exhibits optimized electronic structure and fast intra‐chain charge transport within the high‐aromaticity polymeric skeleton. As a result, the polymer exhibits exceptional proton‐storage redox kinetics, which are evidenced by in‐operando monitoring techniques and theoretical calculations. It achieves a remarkable proton‐storage capacity of 189 mAh g−1 at 2 A g−1 and excellent long‐term cycling stability, with approximately 97.8 % capacity retention over 10,000 cycles. Finally, a high‐performance all‐polymer APB device has been successfully constructed with a desirable capacity retention of 99.7 % after 6,000 cycles and high energy density of 56.3 Wh kg−1. [ABSTRACT FROM AUTHOR]

ABSTRACT Metal–organic framework (MOF) nanozymes have garnered widespread attention in the field of biomimetic catalysis due to their highly controllable porous structure and surface functionalization, enabling them to mimic the catalytic activity and specificity of natural enzymes while offering greater stability and reusability. In recent years, significant progress has been made in the theoretical computation studies of MOF nanozymes' catalytic reactions, providing deep insights into their catalytic and analytical mechanisms. This review comprehensively gathers the latest research progress of theoretical calculation–driven MOF nanozymes on their catalytic mechanisms and applications. First, the methods that can be used for theoretical calculations of MOF nanozymes, especially density functional theory (DFT), are reviewed to help deeply analyze the active site distribution, electron transfer pathways, and adsorption and activation mechanisms of reactants of MOF nanozymes. Subsequently, this review deeply studies the contribution of these theoretical calculation methods to revealing the catalytic reaction mechanism of MOF nanozymes (such as active sites and enzyme‐like activity), especially the specific role of electron transfer and reaction energy changes in key reaction steps. Finally, this review looks forward to the challenges and opportunities in the theoretical computation for the future design and application of MOF nanozymes, especially in accurately predicting catalytic activities, understanding complex reaction mechanisms, and guiding the synthesis of new nanozyme materials. By integrating theoretical calculations with experimental research, the study of MOF nanozymes is expected to forge new avenues in biomimetic catalysis and provide effective strategies for addressing challenges in the fields of sensing, biomedicine, and environmental protection. [ABSTRACT FROM AUTHOR]

Due to its structural complexity and intrinsic sensitivity of bridged aminal junction, 2,6‐diazabicyclo[2.2.2]octane (2,6‐DABCO) has remained a highly desirable target in synthetic chemistry. However, the asymmetric access to this unit is still insufficient and hampered by the need for meticulously created functionalities for intricate double aza‐cyclizations. Herein, we have developed a novel enantio‐ and diastereoselective protocol to access polycyclic chiral 2,6‐DABCOs under metal‐free conditions. This domino process involves the amine‐catalyzed [4+2] annulation between glutaraldehyde and 2‐arylindol‐3‐ones, followed by an acid‐mediated Pictet–Spengler reaction/intramolecular aza‐cyclization cascade sequence with tryptamine by trapping of in situ generated 3‐oxindolium ion intermediate for the first time. Overall, 2,6‐DABCOs fused with medicinally relevant scaffolds were isolated with good yield and excellent stereoselectivity by constructing five new bonds and four stereocenters in a one‐pot operation. [ABSTRACT FROM AUTHOR]

Ammonia is an important raw material for agricultural production, playing a key role in global food production. However, conventional ammonia synthesis resulted in extensive greenhouse gas emissions and huge energy consumption. Recently, researchers have proposed electrocatalytic reverse artificial nitrogen cycle (eRANC) routes to circumvent these issues, which can be driven by electrocatalysis and sustainable electricity. Here, a theoretical and computational perspective on the challenges and opportunities with the comparison with experimental results: electrochemical reduction of nitrate (eNO3RR) and nitrite (eNO2RR), electrochemical reduction of nitric oxide (eNORR) combined with oxidative nitrogen fixation are presented. By comparison, the N2→NO→NH3 route is proposed as the most promising in case the NO solubility can be solved well in reactor design. Its high efficiency of ammonia production is demonstrated. Instead, the eNO3RR can be another choice because it is non‐toxic and the solid‐liquid interface is usually efficient for electrochemical reactions, while its low selectivity at low overpotentials is an issue. These fundamentals highlight the potential and key factors of eRANC as an efficient and sustainable route for ammonia production. [ABSTRACT FROM AUTHOR]

The current work looks at the inhibitory effects of a diolefinic dye, namely 1,4-bis((E)-2-(3-methyl-2,3-dihydrobenzo[d]thiazol-2-yl) vinyl) benzene iodide salt, in relation to CS corrosion mitigation in hydrochloric acid (HCl) environment. This study uses a variety of experimental methodologies, including weight loss (WL) analysis, electrochemical tests, and theoretical considerations. The synergistic effect of diolefinic dye and AgNPs on the corrosion inhibition of CS in 1 M HCl was investigated. The inhibition efficiency (IE) displays a notable enhancement as the concentration of the dye is elevated and as the temperature raises the IE increases. The diolefinic dye exhibited % IE of 83% even at low concentration (1 × 10–4 M) whereas 90% in the presence of (2.26 × 10–10) AgNPs. Tafel graphs demonstrate that the dye follows a mixed type inhibitor. The adsorption of the dye on CS surface follows Langmuir model. Moreover, the influence of temperature and the activation parameters disclose that diolefinic dye is chemisorbed on the CS surface. The synergistic coefficient of the diolefinic dye and AgNPs under various concentration conditions was greater than unity. The surface morphology of CS sheets was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). Density Functional Theory (DFT) calculations provide theoretical support for the inhibitory effects of the examined dye. Notably, there is a high agreement between the findings of practical studies and theoretical expectations. [ABSTRACT FROM AUTHOR]

Enantioselective separation of atenolol (ATL) enantiomers employing carboxymethyl-β-cyclodextrin as chiral selector has been reported in a limited number of studies. However, none of these experimental works achieved enantiomer assignment, precluding the elucidation of the enantiomeric migration order (EMO). In this sense, to elucidate for the first time the fundamental principles governing the enantioselective recognition of atenolol enantiomers, we conducted a comprehensive theoretical study of the formation mechanisms of their inclusion complexes. As main result, based on structural, electronic, and energetic properties, we were able to indicate that (-)-(S)-ATL is anticipated to exhibit a prolonged migration time compared to (+)-(R)-ATL. This differential migration behavior stems from the stronger interaction between (-)-(S)-ATL and the chiral selector, resulting in a more stable inclusion complex and consequently, enhanced retention. These findings highlight the remarkable potential of molecular modeling techniques in deepening our understanding of enantioseparation mechanisms. [ABSTRACT FROM AUTHOR]

Microcrystalline cellulose was subjected to acetylation by different agents in solvent mixtures, composed of the ionic liquids (ILs) 1-butyl-3-methylimidazolium X (X = acetate, BuMeImAcO; chloride, BuMeImCl), and the molecular solvents (MSs), N,N-dimethylacetamide (DMAc) and dimethyl sulfoxide (DMSO). The reactions were carried out under homogeneous conditions using the following acetylation agents: acetic anhydride ((Ac)2O), 1-acetyl-3-methylimidazolium acetate (AcMeImAcO), and vinyl acetate (VA). The efficiency of acetylation was judged by the degree of biopolymer substitution, DS. For all binary solvent mixtures, the order of DS was: AcMeImAcO > (Ac)2O > VA. For the same acetylating agent, the order of DS was: BuMeImAcO-DMSO > BuMeImAcO-DMAc > BuMeImCl-DMSO. We rationalize this dependence of DS on reaction conditions by considering our experimental data and the results of molecular dynamics simulations (MD). Thus, solvent-induced separation of cellulose chains leads to higher acetylation rates, hence larger DS values. The order of biopolymer dissolution/chain separation is attributed to a combination of hydrogen-bonding of the IL anion with cellulose hydroxyl groups, and biopolymer-solvent hydrophobic interactions. The results of MD simulations showed an additional important point: the compositions of the cellulose solvation layers are different from those of bulk solvent mixtures; they are richer in IL ions; this difference affects the values of DS. Thus, theoretical calculations help in choosing the best solvents for cellulose dissolution/derivatization. [ABSTRACT FROM AUTHOR]

[Display omitted] • The hybrid catalysts featuring Fe single atoms and Fe 2 O 3 clusters was fabricated. • Fe SACs/Fe 2 O 3 @NHPC exhibits a surprising ORR activity and high stability. • Fe 2 O 3 clusters can induce electron polarization, thus weakening the *OH desorption. Effectively controlling the electronic configuration of metal sites within single-atom catalysts (SACs) is essential for improving their oxygen reduction reaction (ORR) performance. Here, we construct hybrid catalysts featuring Fe single atoms and Fe 2 O 3 clusters (Fe SACs/Fe 2 O 3 @NHPC) to realize highly efficient ORR. Specifically, the Fe SACs/Fe 2 O 3 @NHPC delivers a remarkable half-wave potential (E 1/2) of 0.893 V and endures 30,000 cycles with only 12 mV E 1/2 loss in alkaline media. Liquid zinc–air batteries (ZABs) utilizing Fe SACs/Fe 2 O 3 @NHPC output a power density of 192.7 mW cm−2 and demonstrate rechargeability over 370 h without noticeable voltage degradation. Furthermore, theoretical calculations indicate that the axially coordinated Fe 2 O 3 clusters significantly promote electronic delocalization in the 3 d orbitals of the Fe sites. This electronic structure regulation strategy optimizes the hybridization between Fe-3 d orbitals and O-2 p orbitals, thereby facilitating the *OH dissociation process. This research not only provides intensive insight into the synergistic interactions and complementary effects between single-atom sites and clusters in hybrid catalysts but also lays the groundwork for designing SACs. [ABSTRACT FROM AUTHOR]

[Display omitted] Electroreduction of CO 2 and NO 2 − to urea (ECNU) provides a fascinating method for concurrently migrating polluted NO 2 − and producing value-added urea. In this study, atomically dispersed W on MoS 2 (W 1 /MoS 2) is designed as an efficient ECNU catalyst, which exhibits the highest Faraday efficiency of 60.11 % and urea yield rate of 35.80 mmol h−1 g−1 in flow cell. Atomic characterizations reveal that W single atoms exist as isolated W 1 -S 3 moieties on MoS 2. Combined theoretical calculations and operando spectroscopic measurements demonstrate that the enhanced ECNU performance of W 1 /MoS 2 arises from the construction of W 1 -S 3 moieties that can promote C N coupling and hydrogenation energetics, whilst suppressing the competing side reactions. [ABSTRACT FROM AUTHOR]

Synergistically improvement of the catalytic activity, durability and anti-CO poisoning via the metal–metal oxide strong interactions between PtFe NPs and CeO 2 and the oxygen vacancies in CeO 2. [Display omitted] • Pt 3 Fe@CeO 2 /MWCNTs exhibited high activity, stability, and CO tolerance during MOR. • Strong metal–metal oxide interaction between PtFe NPs and CeO 2 can stabilize PtFe NPs against migration/agglomeration. • The d-orbital electronic configuration of Pt is optimized by combining the PtFe intermetallic with metal–metal oxide interaction. • The PtFe intermetallic coupled with oxygen vacancies in CeO 2 facilitates the adsorption of *OH and oxidation of *CO, boosting the performance of MOR. Coordinating the interfacial interaction between Pt-based nanoparticles (NPs) and supports is a significant strategy for the modulation of d-orbital electronic configuration and the adsorption behaviors of intermediates, which is of critical importance for boosting electrocatalytic performance. Herein, we demonstrated a specific synergy effect between the ordered PtFe intermetallic and neighboring oxygen vacancies (Ov), which provides an "ensemble reaction pool" to balance the barriers of both the activity, stability, and CO poisoning issues for the methanol oxidation reaction (MOR). In our proposed "ensemble reaction pool", the deprotonation of methanol occurs on the Pt site to form the intermediate *CO, where the strain derived from the PtFe intermetallic could alter the d-orbital electronic configuration of Pt, intrinsically weakening the *CO adsorption energy, and Ov in CeO 2 promote hydroxyl species (*OH) adsorption, which will react with *CO, facilitating the dissociative adsorption of *CO, thus cooperatively enhancing the performance of MOR. The X-ray absorption fine structure (XAFS) analyses reveal the electron transfer in CeO 2 and then convert Ce4+ to Ce3+. The density functional theory (DFT) calculations revealed that introducing Fe induces strain could modify the d-band center of Pt, and thus lower the energy barrier of the potential-determining step. Meanwhile, the introduction of CeO 2 can favor the *OH adsorption, speeding up the oxidation and removal of *CO blocked at the Pt site. Furthermore, the determined atomic arrangement and surface composition of PtFe intermetallic further guarantee the stability of MOR by suppressing less-noble metal into the electrolyte. [ABSTRACT FROM AUTHOR]

Low‐cost organic photovoltaic (OPV) devices have shown enormous potential in large‐scale industrial applications. And it has attracted widespread attention in the past few decades. However, the photophysical characteristics of these budget‐friendly materials haven't been explored much. Here, low‐cost small materials, including small molecule 1 (asm1) with ortho‐fluorinated side chain and small molecule 2 (asm2) with meta‐fluorinated side chain were selected to probe the fluorination effect on the absorption spectra, electrochemical energy levels, electrostatic potential (ESP), etc. The results show that the molecules asm1 and asm2 have good planarity of the backbone. And the meta‐fluorinated side chain of asm2 contributes more to the highest occupied molecular orbital and less to the lowest unoccupied molecular orbital than asm1. Moreover, differences in ESP are found between donor and acceptor materials. Furthermore, strong and broad light absorption in the visible region of these low‐cost molecules is observed, resulting in a better short‐circuit current density for the devices constructed by the donors asm1, asm2, and acceptor Y6. In addition, more charge transfer mechanisms are characterized for the asm1/Y6 system. The introduction of ortho‐fluorination in the conjugated side chain of the molecule is a favorable approach, which will provide theoretical guidance for further molecular design experiments. [ABSTRACT FROM AUTHOR]

The aggregation of β‐amyloid peptide (Aβ) is associated with neurodegenerative diseases such as Alzheimer's disease (AD). Several therapies aimed at reducing the aggregation of this peptide have emerged as potential strategies for the treatment of AD. This paper describes the design and preparation of new hybrid molecules based on steroids, selenosugars, and [60]fullerene as potential inhibitors of Aβ oligomerization. These moieties were selected based on their antioxidant properties and possible areas of interaction with the Aβ. Cyclopropanations between C60 and malonates bearing different steroid and selenosugar moieties using the Bingel–Hirsch protocol have enabled the synthesis of functionalized molecular hybrids. The obtained derivatives were characterized by physical and spectroscopic techniques. Theoretical calculations for all the selenium compounds were performed using the density functional theory DFT/B3LYP‐D3(BJ)/6‐311G(2d,p) predicting the most stable conformations of the synthesized derivatives. Relevant geometrical parameters were investigated to relate the stereochemical behavior and the spectroscopic data obtained. The affinity of the compounds for Aβ‐peptide was estimated by molecular docking simulation, which predicted an increase in affinity and interactions for Aβ for the hybrids containing the C60 core. In addition, parameters such as lipophilicity, polar surface area, and dipole moment were calculated to predict their potential interaction with membrane cells. [ABSTRACT FROM AUTHOR]

Electrocatalytic reduction of NO2− to NH3 (NO2RR) presents a fascinating approach for simultaneously migrating NO2− pollutants and producing valuable NH3. In this study, single‐atom Rh‐alloyed copper (CuRh1) is explored as a highly active and selective catalyst toward the NO2RR. Combined theoretical calculations and in situ FTIR/EPR spectroscopic experiments uncover the synergistic effect of Rh1 and Cu to promote the NO2RR energetics of CuRh1 through a tandem catalysis pathway, in which Rh1 activates the preliminary adsorption and hydrogenation of NO2− (NO2− → *NO2 → *NOOH → *NO), while the generated *NO on Rh1 is then transferred on Cu substrate which promotes the rate‐determining step of *NO → *NHO toward the NH3 synthesis. As a result, CuRh1 equipped in a flow cell presents an unprecedented NH3 yield rate of 2191.6 µmol h−1 cm−2 and NH3‐Faradaic efficiency of 98.9% at a high current density of 322.5 mA cm−2, as well as long‐term stability for 100 h electrolysis. [ABSTRACT FROM AUTHOR]

This research examines vanadium‐deficient V2C MXene, a two‐dimensional (2D) vanadium carbide with exceptional electrochemical properties for rechargeable zinc‐ion batteries. Through a meticulous etching process, a V‐deficient, porous architecture with an expansive surface area is achieved, fostering three‐dimensional (3D) diffusion channels and boosting zinc ion storage. Analytical techniques like scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller, and X‐ray diffraction confirm the formation of V2C MXene and its defective porous structure. X‐ray photoelectron spectroscopy further verifies its transformation from the MAX phase to MXene, noting an increase in V3+ and V4+ states with etching. Cyclic voltammetry reveals superior de‐zincation kinetics, evidenced by consistent V3+/V4+ oxidation peaks at varied scanning rates. Overall, this V‐deficient MXene outperforms raw MXenes in capacity and rate, although its capacity diminishes over extended cycling due to structural flaws. Theoretical analyses suggest conductivity rises with vacancies, enhancing 3D ionic diffusion as vacancy size grows. This work sheds light on enhancing V‐based MXene structures for optimized zinc‐ion storage. [ABSTRACT FROM AUTHOR]

Copyright of Precious Metals / Guijinshu is the property of Precious Metals Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A series of homoleptic Ni bis‐1,1‐dithiolates, [Ni(S2C2RR′)2]2− (R=CN, R′=CN, CO2Et, CONH2, Ph, Ph‐4‐Cl, Ph‐4‐OMe, Ph‐4‐NO2, Ph‐3‐CF3, Ph‐4‐CF3, Ph‐4‐CN; R=NO2, R′=H; R=R′=CO2Et) have been synthesized from the reaction of the alkali metal salt of the ligand and nickel chloride, and isolated as tetraphenylphosphonium or tetrabutylammonium salts. The complexes were characterized by X‐ray crystallography, high‐resolution mass spectrometry, and infrared (IR), nuclear magnetic resonance (NMR) and electronic absorption spectroscopies. The molecular structures show a rigidly square planar Ni(II) center linking two four‐membered chelate rings whose dimensions are constant across the series. The electronic effect of the ligand substituent is revealed in the 13C NMR and electronic spectra, and corroborated by density functional calculations. Electron withdrawing groups deshield the low‐field CS2 resonance, and the signature charge transfer band in the visible region is red‐shifted. These observables have been accurately reproduced computationally, and revealed the Ni contribution to the ground state diminishes with decreasing electron withdrawing capacity of the ligand substituent. In contrast to 1,2‐dithiolates, the redox inactivity afforded by 1,1‐dithiolates stems from the smaller chelate ring and substantially reduced sulfur content that is key to stabilizing the radical form. [ABSTRACT FROM AUTHOR]

Compounds containing the thiophene moiety find several applications in physics and chemistry, such as electrical conduction, which depends on specific conformations to properly exhibiting the desired properties. In turn, chalcogen bonding has found to modulate the conformation of some N‐thiophen‐2‐ylfomamides. Since halogens participate in a kin interaction (halogen bonding) and are abundant in agrochemicals, pharmaceuticals, and materials, we have quantum‐chemically explored the interaction between organic halogen and thiophene as a conformational modulator in some model compounds. Although such interaction indeed appears, as demonstrated by atoms in molecules and natural bond orbital analysis, it is inefficient to control the conformational equilibrium. An energy decomposition analysis scheme demonstrated that halomethane and thiophene tend to move away from one another due to a core component (Pauli repulsion and exchange), which is mainly due to a deformation term. Therefore, chalcogen bonds with halogens appear weaker than with other chalcogens. [ABSTRACT FROM AUTHOR]

Developing potential hole transport materials (HTMs) is an effective approach to reduce carrier nonradiative recombination and improve the efficiency of perovskite solar cells (PSCs). To investigate the intermolecular and interfacial interactions of HTMs in PSC devices, two molecules (RQ7 and RQ8) with substituent group functionalization are designed by isomerizing ‐F and ‐SMe in the para‐ and ortho‐positions on the side chain of carbazole diphenylamine‐based HTMs. Theoretical simulations indicate that the functionalization of substituent groups in HTMs alters their dipole moments and electronic structures, as well as their intermolecular interactions, hole transport capabilities, and interfacial interactions at the HTMs/perovskite interface. Experimental results show that RQ8 exhibited higher hole mobility, better film‐forming ability, and reduced electron‐hole recombination, resulting in RQ8‐based PSC devices achieving a higher power conversion efficiency than those based on RQ7. Herein, it is demonstrated that isomerous functionalization of substituent groups in carbazole diphenylamine‐based HTMs is a feasible strategy for controlling and regulating the intermolecular and interfacial interactions of HTMs in PSC applications. [ABSTRACT FROM AUTHOR]

Developing highly active and stable electrocatalysts is essential for the large‐scale production of hydrogen from alkaline water. In this work, Ag single atoms and nanoparticles co‐decorated Co hydro(oxy)oxide (Ag SAs&NPs@CoO(O)H) is synthesized by a facile one‐step approach. Notably, the overpotential of Ag SAs&NPs@CoO(O)H is 200 mV at current density of 50 mA cm−2 during oxygen evolution reaction (OER). Meanwhile, it can display the mass activity of 637.47 A g−1Ag under 300 mV, which is 212.49 times higher than that of commercial IrO2. Moreover, the assembled Pt/C // Ag SAs&NPs@CoO(O)H system only requires 1.9 V to reach an industrial current density of 1000 mA cm−2 in alkaline water electrolyzer and exhibits excellent stability at large current density of 1000 mA cm−2. Furthermore, in situ Raman spectroscopy analysis coupled with theoretical calculations reveals an novel active site switching mechanism is found on Ag SAs&NPs@CoO(O)H. Specifically, the O* preferentially generates on the Ag NPs and then switches toward the Co3+ site in CoO(O)H to produce OOH* and O2. Meanwhile, the Ag SAs in the lattice of CoO(O)H can exert an inhibitory force on the reconstruction process of CoOOH to Co(OH)2, resulting in excellent anti‐dissolution stability. [ABSTRACT FROM AUTHOR]

Reactions of bis(benzene)chromium (Bz2Cr) and ozone (O3) were studied using low-temperature argon matrix-isolation infrared spectroscopy with supporting DFT calculations. When Bz2Cr and O3 were co-deposited, they reacted upon matrix deposition to produce two new prominent peaks in the infrared spectrum at 431   c m − 1 and 792   c m − 1 . These peaks increased upon annealing the matrix to 35 K and decreased upon UV irradiation at λ = 254 nm. The oxygen-18 and mixed oxygen-16,18 isotopic shift pattern of the peak at 792   c m − 1 is consistent with the antisymmetric stretch of a symmetric ozonide species. DFT calculations of many possible ozonide products of this reaction were made. The formation of a hydrogen ozonide (H2O3) best fits the original peaks and the oxygen-18 isotope shift pattern. Energy considerations lead to the conclusion that the chromium-containing product of this reaction is the coupled product benzene-chromium-biphenyl-chromium-benzene (BzCrBPCrBz). 2 B z 2 C r + O 3 → H 2 O 3 + B z C r B P C r B z ,   ∆ E c a l c = − 52.13 k c a l / m o l . [ABSTRACT FROM AUTHOR]

Controlling the optical activity of halide perovskite materials through modulation of the coordination configurations of the metal ions is important. Herein, a novel manganese‐based halide, specifically diaquatetrakis(methyldiphenylphosphine oxide)manganese(II) tetrachloridomanganate(II), [Mn(C13H13OP)4(H2O)2][MnCl4] or [Mn(MDPPO)4(H2O)2][MnCl4] (MDPPO is methyldiphenylphosphine oxide), was synthesized through the solvothermal reaction of MnCl2 with the neutral molecule MDPPO. In this compound, [Mn(MDPPO)4(H2O)2]2+ acts as the cation, while [MnCl4]2− serves as the anion, enabling the co‐existence of tetrahedral and octahedral structures within the same system. Remarkably, the compound exhibits efficient red‐light emission at 662 nm, distinct from the green‐light emission typically observed in MnX4‐based halides. Theoretical calculations show that the red emission comes from the charge transfer from the MDPPO to the Mn2+ of [MnCl4]2−. This work provides a new perspective for the design and synthesis of red‐light‐emitting manganese‐based halides with unique structures. [ABSTRACT FROM AUTHOR]

Nucleophilic fluorination of aromatic rings can be done via a cross-coupling reaction catalyzed by palladium and biaryl monophosphine ligands such as AlPhos. Nevertheless, aromatic fluorination via palladium catalysis can lead to regioisomers, a serious problem for this kind of reaction. An ortho-deprotonation mechanism was proposed for this reaction in previous studies. However, this mechanism does not explain why the ortho product is not formed from para and meta substrates, and the details of the mechanism are not fully understood yet. This theoretical work discloses the mechanism behind regioisomers formation, which takes place via unimolecular ortho-elimination of HF. The computed free energy profile of the reaction was followed by a detailed microkinetic analysis, which explain the experiments quantitatively. The present study shows that the rotation of the aryne coordinated to the palladium to form a complex leading to the ortho product is critical for regioselectivity. This rotation has a high free energy barrier due to steric repulsion with the adamantane group of the ligand. Such a feature impedes the formation of ortho product from para and meta substrates and allows the formation of the ortho product selectively from the ortho substrate. [ABSTRACT FROM AUTHOR]

Four new polyketides, namely furantides A–B (1–2), talamin E (3) and arugosinacid A (4), and two known polyketides were obtained from the mangrove-derived fungus Penicillium sp. HDN15-312 using the One Strain Many Compounds (OSMAC) strategy. Their chemical structures, including configurations, were elucidated by detailed analysis of extensive NMR spectra, HRESIMS and ECD. The DPPH radicals scavenging activity of 3, with an IC50 value of 6.79 µM, was better than vitamin C. [ABSTRACT FROM AUTHOR]

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This review article aims to provide an overview of the strategies employed to prepare noble gas anions under different environments and experimental conditions, and of the bonding motifs typically occurring in these species. Observed systems include anions fixed into synthesized salts, detected in the gas phase or in high‐pressure devices. The major role of the theoretical calculations is also highlighted, not only in support of the experiments, but also as effective in predicting still unreported species. The chemistry of noble gas anions overall appears as a varied and rich paint, offering fascinating opportunities for both experimentalists and theoreticians. [ABSTRACT FROM AUTHOR]

It is of great importance and worthy of efforts to give a clear structure–property relationship and microscopic mechanism of fluorescence emitters with high quantum yield. In this work, we perform a detailed computational investigation to give an explanation to the high efficiency of a fluorescence emitter XBTD‐NPh based TADF sensitized fluorescence (TSF) OLEDs, and construct a symmetry structure DSBNA‐BTD. Theoretical calculations show that XBTD‐NPh is a long‐time phosphorescent material at 77 K and TADF is attributed to the RISC of T1 to S1 state. For DSBNA‐BTD, excitons arrived at T1 state comes to a large rate of nonradiatively path to the ground state, meaning it is may not be an efficient TADF molecule. For both molecules, the fast IC between T2 and T1 state results in that the hot exciton channel T1‐Tn‐S1 makes no contribution to the TADF. [ABSTRACT FROM AUTHOR]

AbstractThe inhibition effect of N2, N6-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)pyridine-2,6-diamine (MH-PA) on the corrosion of C35E steel in 1 M HCl solution was investigated employing potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), Fourier-transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), contact angle, X-ray photoelectron spectroscopy (XPS) methods, UV-visible spectroscopy, and theoretical calculation methods. The inhibition efficiency increased with increasing MH-PA concentration and decreased with increasing temperature, attaining 98% inhibition efficiency at 10−3M under 303K. PDP studies indicated that MH-PA is a mixed-type corrosion inhibitor and its adsorption mode conforms to Langmuir isotherm. UV-visible and FTIR spectroscopy support MH-PA adsorption over the C35E steel surface. The surface analysis through SEM, EDS, AFM, and contact angle corroborates the formation of the protective layer of MH-PA molecules on the C35E steel surface. In addition, XPS analysis revealed the formation of an N-Fe bond. Thermodynamic properties revealed that MH-PA has both physical and chemical adsorption behavior. Molecular dynamics simulations manifest that MH-PA molecules adsorb parallel to the Fe (110) surface. [ABSTRACT FROM AUTHOR]

Context: The conversion of carbon dioxide (CO2) to formic acid (FA) through hydrogenation using 1-ethyl-2,3- dimethyl imidazolium nitrite (EDIN) ionic liquid was studied to understand the catalytic roles within EDIN. CO2 hydrogenation in various solvents has been explored, but achieving high efficiency and selectivity remains challenging due to the thermodynamic stability and kinetic inertness of CO2. This study explored two mechanistic pathways through theoretical calculations, revealing that the nitrite (NO2−) group is the most active site. The oxygen site on nitrite favorably activates H2, while the nitrogen site shows a minor activation barrier of 108.90 kJ/mol. The Gibbs energy variation indicates stable FA formation via EDIN, suggesting effective hydrogen (H2) activation and subsequent CO2 conversion. These insights are crucial for developing improved catalytic sites and processes in ionic liquid catalysts for CO2 hydrogenation. Methods: Quantum chemical calculations were conducted using the ORCA software package at the Restricted Hartree-Fock (RHF) and density functional theory (DFT) levels. The RHF method, known for its predictive abilities in simpler systems, provided a baseline description of electronic structures. In contrast, DFT was employed for its effectiveness in complex interactions involving significant electron correlation. A valence triple-zeta polarization (def2-TZVPP) basis set was employed for both RHF and DFT, ensuring accurate and correlated calculations. The B3LYP functional was utilized for its rapid convergence and cost-efficiency in larger molecules. Dispersion corrected functionals (DFT-D) addressed significant dispersion forces in ionic liquids, incorporating Grimme's D2, D3, and D4 corrections. Geometry optimizations, kinetics, and thermodynamic calculations were performed in the gas phase. The Nudged Elastic Band Transition State (NEB-TS) approach, combining Climbing Image-NEB (CINEB) and Eigenvector-Following (EF) methods, was used to find the minimum energy path (MEP) between reactants and products. Thermochemical analyses based on vibrational frequency calculations evaluated properties such as Enthalpy, Entropy, and Gibbs energy using ideal gas statistical mechanics. [ABSTRACT FROM AUTHOR]

The current study explores the film forming ability of a new additive Methyl p-toluene sulfonate (MPTS) on the LiMn2O4 (LMO) electrode and its effect on the electrochemical characteristics of lithium-ion battery. Based on the density functional theory analysis of the ionization energy (AIE) of MPTS and carbonate solvents, it was found that MPTS possesses the lowest AIE at 693.2 kJ/mol, suggesting a higher susceptibility to oxidation compared to the electrolyte solvents. Electrochemical and physicochemical analyses including linear sweep voltammetry, electrochemical impedance spectroscopy, field-emission scanning microscopy, indicated that the electrolyte with MPTS is prone to create a protective film with low impedance on the cathode electrode, which enhances the stability of the electrolyte and electrode upon battery cycling. The LMO/Li half-cell with 1.5% MPTS exhibits outstanding cyclic performance, retaining 90.53% of its capacity after 100 cycles, in comparison to 81.84% for the pristine electrolyte at high voltage. This improvement is because of the creation of a protective sulfur-containing layer on the cathode surface, which effectively prevents electrolyte degradation, reduces interfacial impedance, and enhances overall battery performance. [ABSTRACT FROM AUTHOR]

The growth of coherently engineered porous bimetal (PBM) nanostructures shows great progress in electrochemical carbon dioxide (CO2) utilization. This is due to their remarkable catalytic and physicochemical merits that present an encouraging approach for CO2 conversion into valuable products (i.e., fuels and chemicals). Hence, this review presents recent advances in experimental, in-situ analysis and theoretical studies of PBM electrocatalysts, including PBM Cu-based and PBM Cu-free electrocatalysts, toward CO2 reduction reaction (CO2RR) and comprehend its fundamental mechanisms. Various synthesis strategies were utilized to construct PBM nanostructures with distinct compositions, morphology, and synergism for excellent CO2RR activity, stability and product selectivity. As corroborated by theoretical calculations that revealed beneficial electronic features and reaction routes with facile adsorption energies for reactant (CO2) and intermediate species on the various active sites of PBM nanostructures in easing the CO2RR. Future research efforts should establish robust framework for experimental, in-situ analysis, theoretical simulations and automated machine learning in developing next-generation electrochemical CO2 utilization technologies with PBM nanostructures. Finally, this study emphasizes the potential of PBM nanostructures for efficient electrochemical CO2 utilization and provides a pathway to sustainable and inexpensively viable carbon-neutrality.

As part of the development of a new organic entity, we synthesized a new series of Schiff bases belonging to the imidazo[1,2-a]pyridine (IMP) family, named: (E)-2-methoxy-4-(((2-phenylimidazo[1,2-a]pyridin-3-yl)imino)methyl)phenol(IM1) and (E)-4-(((2-phenylimidazo[1,2-a]pyridine-3-yl)imino)methyl)phenol (IM2). Molecular structures were confirmed through chemical analyses, including nuclear magnetic resonance (NMR) and mass spectroscopy. In order to develop new organic ligands to inhibit mild steel corrosion in 1M HCl solution, various weight loss and electrochemical methods, such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP), along with surface visualization through scanning electron microscopy (SEM) and atomic force microscopy (AFM), were employed. EIS results revealed excellent inhibition by compounds IM1 and IM2 (98% and 92%, respectively) at a concentration of 1 mM. These findings were supported by the observation of a protective layer formation during prolonged immersion of mild steel in a corrosive solution, with or without inhibitors. Finally, theoretical studies such as density functional theory (DFT) and molecular dynamics simulations were conducted to explore the adsorption behaviour of inhibitors IM1 and IM2 on the iron surface, providing insight into the inhibitor-metal interaction during the adsorption process.

Abstract Flexible electrode design with robust structure and good performance is one of the priorities for flexible batteries to power emerging wearable electronics, and organic cathode materials have become contenders for flexible self‐supporting electrodes. However, issues such as easy electrolyte solubility and low intrinsic conductivity contribute to high polarization and rapid capacity decay. Herein, we have designed a flexible self‐supporting cathode based on perylene‐3,4,9,10‐tetracarboxylic dianhydride (PTCDA), interfacial engineering enhanced by polypyrrole (PPy), and carbon nanotubes (CNTs), forming the interconnected and flexible PTCDA/PPy/CNTs using polymerization reaction and vacuum filtration methods, effectively curbing those challenges. When used as the cathode of sodium‐ion batteries, PTCDA/PPy/CNTs exhibit excellent rate capability (105.7 mAh g−1 at 20 C), outstanding cycling stability (79.4% capacity retention at 5 C after 500 cycles), and remarkable wide temperature application capability (86.5 mAh g−1 at −30°C and 115.4 mAh g−1 at 60°C). The sodium storage mechanism was verified to be a reversible oxidation reaction between two Na+ ions and carbonyl groups by density functional theory calculations, in situ infrared Fourier transform infrared spectroscopy, and in situ Raman spectroscopy. Surprisingly, the pouch cells based on PTCDA/PPy/CNTs exhibit good mechanical flexibility in various mechanical states. This work inspires more rational designs of flexible and self‐supporting organic cathodes, promoting the development of high‐performance and wide‐temperature adaptable wearable electronic devices.

In the quest for materials that can withstand the rigors of modern engineering applications, high-entropy alloys (HEAs) have emerged as a frontier in material science owing to their unprecedented combination of properties. This review focuses on intricate thermodynamic and computational modeling to guide the design and optimization of HEAs. By dissecting the foundational ''four core effects'' intrinsic to HEAs—high entropy, sluggish diffusion, severe lattice distortion, and cocktail effect—we illuminate the path towards predictable and tailored material properties. Central to the present discourse is the application of valence electron concentration (VEC) and cutting-edge strategies, including the CALculation of PHAse Diagrams (CALPHAD) method, first-principles approach, and machine-learning algorithms, which collectively empower the prediction and understanding of HEA behavior. Through a novel case study of a septenary equiatomic Ni-Al-Co-Cr-Cu-Mn-Ti HEA, this analysis demonstrates the utility of these computational tools in unveiling the alloy's phase stability and microstructural evolution, reinforcing the synergy between theoretical predictions and experimental validation. Furthermore, the review explores the burgeoning applications of HEAs across diverse sectors, such as aerospace, automotive, energy, and biomedical engineering, highlighting their transformative potential. Despite these advancements, challenges such as empirical design limitations, processing complexities, and the need for comprehensive databases are acknowledged, setting the stage for future exploration. This review not only charts a course for the rational design of HEAs, but also envisages their role in advancing material science towards novel applications, urging a concerted effort to overcome existing hurdles and explore uncharted territories in HEA research.

Chalcogenide cathodes with multi‐electron transfer characteristics are indispensable to aluminum‐ion batteries (AIBs). Nevertheless, their grievous capacity degradation and sluggish reaction kinetics remain fundamental challenges for the practical application. Herein, a Cu2S/Ni3S2 multiphase structure within the metal‐organic frame (MOF) derived carbon decoration layer (CNS@MC) is constructed to elevate the intrinsic electronic properties of chalcogenide cathode and realize high‐performance AIBs. The existence of outer carbon layer and strong orbital interaction at inner heterointerfaces eliminates the bandgap and arises more electrons at Fermi level, efficiently reducing the energy barrier for electron transfer and achieving high reactivity within cathodes. The CNS@MC also presents a strong electronic interaction with active solvent groups, which is beneficial to capture Al3+ and facilitate the three‐electron charge‐storage reactions. Experimental results demonstrate that the tailored CNS@MC cathode possesses superior redox kinetics due to the sufficient surface area and rapid Al‐ion diffusion during cycling. Meanwhile, the robust CNS@MC delivers ultra‐high electrochemical stability (131.1 mAh g−1 over 3500 cycles) with high coulombic efficiency and outstanding rate performance. This work offers new opportunities for optimizing the intrinsic properties of the chalcogenide electrodes based on MOF derivatives and heterostructure, providing novel thoughts for designing high‐performance AIBs. [ABSTRACT FROM AUTHOR]

As a promising candidate ceramic for using in harsh environments, Cr 2 AlC ternary carbide possesses numerous unique properties at elevated temperatures. Herein, high-purity Cr 2 AlC powders had been synthesized by using a facile method with a mixture of Cr 7 C 3 , Cr 3 C 2 and Al powders at 1200 °C for 3 h. Subsequently, the oxidation behaviors of Cr 2 AlC powders were investigated in dry air and pure steam at temperatures ranging from 900 to 1100 °C, respectively. In addition, the oxidation products were characterized and the mass gain curves were analyzed via the real physical picture (RPP) kinetic model. As a result, thicker Al 2 O 3 -rich oxide scale and porous Cr 7 C 3 subscale were generated during dry air oxidation compared to pure steam oxidation. Notably, the oxidative active energy of Cr 2 AlC was 446.5 kJ/mol in pure steam, while in dry air it was decreased by 14.4%. Theoretical calculations further verified that Cr 2 AlC oxidizes more sluggishly in steam than in dry air. [ABSTRACT FROM AUTHOR]

Spectroscopic studies (FT-IR, Raman, 1H, and 13C NMR, UV-VIS) of caffeic acid (CFA) and its conjugates, i.e., caftaric acid (CTA), cichoric acid (CA), and cynarin (CY), were carried out. The antioxidant activity of these compounds was determined by a superoxide dismutase (SOD) activity assay and the hydroxyl radical (HO•) inhibition assay. The cytotoxicity of these compounds was performed on DLD-1 cell lines. The molecules were theoretically modeled using the B3LYP-6-311++G(d,p) method. Aromaticity indexes (HOMA, I6, BAC, Aj), HOMO and LUMO orbital energies and reactivity descriptors, NBO electron charge distribution, EPS electrostatic potential maps, and theoretical IR and NMR spectra were calculated for the optimized model systems. The structural features of these compounds were discussed in terms of their biological activities. [ABSTRACT FROM AUTHOR]

Mebendazole (MBZ) is a benzimidazole carbamate anthelmintic used worldwide for the treatment and prevention of parasitic disorders in animals and humans. A large number of in vivo and in vitro studies have demonstrated that MBZ also has anticancer activity in multiple types of cancers. After oral administration, the phenylketone moiety of MBZ is rapidly reduced to the hydroxyl group to form the chiral hydroxy metabolite (MBZ-OH). To the best of our knowledge, there is no information in the literature on the stereochemical course of transformation and the anthelmintic and antitumor activity of individual enantiomers of MBZ-OH. In the present study, we describe in detail the direct HPLC resolution of MBZ-OH on a 100 mm × 4.6 mm Chirapak IG-3 column packed with 3 μm silica particles containing amylose (3-chloro-5-methylphenylcarbamate) as a selector. At 25 °C and using pure methanol as the mobile phase, the enantioseparation and resolution factors were 2.38 and 6.13, respectively. These conditions were scaled up at a semi-preparative scale using a 250 mm × 10 mm Chiralpak IG column to isolate multi-milligram amounts of both enantiomeric forms of the chiral metabolite. The chiroptical properties of the collected enantiomers were determined and, through a theoretical study, were related to the more stable conformations of MBZ-OH. The first and second eluted enantiomers were dextrorotatory and levorotatory, respectively, in dimethylformamide solution. Finally, by recording the retention factors of the enantiomers as the water content in the water–acetonitrile mobile phases was progressively varied, U-shaped retention maps were generated, indicating a dual and competitive hydrophilic interaction liquid chromatography and reversed-phase liquid chromatography retention mechanism on the Chirapak IG-3 chiral stationary phase. [ABSTRACT FROM AUTHOR]

Although the crystals of coordination polymer {[CuCl(μ-O,O'-L-Br2Tyr)]}n (1) (L-Br2Tyr = 3,5-dibromo-L-tyrosine) were formed under basic conditions, crystallographic studies revealed that the OH group of the ligand remained protonated. Two adjacent [CuCl(L-Br2Tyr)] monomers, bridged by the carboxylate group of the ligand in the syn-anti bidentate bridging mode, are differently oriented to form a polymeric chain; this specific bridging was detected also by FT-IR and EPR spectroscopy. Each Cu(II) ion in polymeric compound 1 is coordinated in the xy plane by the amino nitrogen and carboxyl oxygen of the parent ligand and the oxygen of the carboxyl group from the symmetry related ligand of the adjacent [Cu(L-Br2Tyr)Cl] monomer, as well as an independent chlorine ion. In addition, the Cu(II) ion in the polymer chain participates in long-distance intermolecular contacts with the oxygen and bromine atoms of the ligands located in the adjacent chains; these intramolecular contacts were also supported by NCI and NBO quantum chemical calculations and Hirshfeld surface analysis. The resulting elongated octahedral geometry based on the [CuCl(L-Br2Tyr)] monomer has a lower than axial symmetry, which is also reflected in the symmetry of the calculated molecular EPR g tensor. Consequently, the components of the d-d band obtained by analysis of the NIR-VIS-UV spectrum were assigned to the corresponding electronic transitions. [ABSTRACT FROM AUTHOR]

The bottom-up fabrication of supramolecular and self-assembly on various substrates has become an extremely relevant goal to achieve prospects in the development of nanodevices for electronic circuitry or sensors. One of the branches of this field is the self-assembly of functional molecular components driven through non-covalent interactions on the surfaces, such as van der Waals (vdW) interactions, hydrogen bonding (HB), electrostatic interactions, etc., allowing the controlled design of nanostructures that can satisfy the requirements of nanoengineering concepts. In this context, non-covalent interactions present opportunities that have been previously explored in several molecular systems adsorbed on surfaces, primarily due to their highly directional nature which facilitates the formation of well-ordered structures. Herein, we review a series of research works by combining STM (scanning tunneling microscopy) with theoretical calculations, to reveal the processes used in the area of self-assembly driven by molecule Landers equipped with functional groups on the metallic surfaces. Combining these processes is necessary for researchers to advance the self-assembly of supramolecular architectures driven by multiple non-covalent interactions on solid surfaces. [ABSTRACT FROM AUTHOR]

This study describes the synthesis of novel chalconethiocarbohydrazones derived from 2′-hydroxychalcone and thiocarbohydrazide as potential drugs. The monothiocarbohydrazone (M1) and bisthiocarbohydrazone (M2) compounds were obtained by condensing thiocarbohydrazide with 2′-hydroxychalcone [1-(2-hydroxyphenyl)−3-phenyl-2-propen-1-one] at 1/1 and 1/2 mol ratios. The synthesized compounds were characterized by elemental analysis, 1H NMR, FT-IR and UV-Vis spectroscopic techniques. The crystal structures of M1 and M2 were solved using single crystal X-ray diffraction method. The total antioxidant capacities of synthesized thiocarbohydrazones were determined by Cupric Reducing Antioxidant Capacity (CUPRAC) method. It was investigated also the radical scavenging activities of these compounds with 2,2-Diphenyl-1-picrylhydrazyl (DPPH) method. When compared to standard compound Trolox, both of the compounds showed good antioxidant activity. For the new compounds, Conceptual Density Functional Theory (CDFT) computations were performed to compute important quantum chemical reactivity descriptors. The chemical reactivities of the studied chemical systems were compared via well-known electronic structure rules of CDFT. Experimentally determined antioxidant activities of the synthesized compounds were supported with Molecular Docking analyses. [ABSTRACT FROM AUTHOR]

The photocatalyst (PC) zinc tetraphenylporphyrin (ZnTPP) is highly efficient for photoinduced electron/energy transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerization. However, ZnTPP suffers from poor absorbance of orange light by the so-called Q-band of the absorption spectrum (maximum absorption wavelength λ max = 600 nm, at which molar extinction coefficient ε max = 1.0 × 10 4 L/(mol·cm)), hindering photo-curing applications that entail long light penetration paths. Over the past decade, there has not been any competing candidate in terms of efficiency, despite a myriad of efforts in PC design. By theoretical evaluation, here we rationally introduce a peripheral benzo moiety on each of the pyrrole rings of ZnTPP, giving zinc tetraphenyl tetrabenzoporphyrin (ZnTPTBP). This modification not only enlarges the conjugation length of the system, but also alters the a 1 u occupied π molecular orbital energy level and breaks the accidental degeneracy between the a 1 u and a 2 u orbitals, which is responsible for the low absorption intensity of the Q-band. As a consequence, not only is there a pronounced hyperchromic and bathochromic effect ( λ max = 655 nm and ε max = 5.2 × 10 4 L/(mol·cm)) of the Q-band, but the hyperchromic effect is achieved without increasing the intensity of the less useful, low wavelength absorption peaks of the PC. Remarkably, this strong 655 nm absorption takes advantage of deep-red (650–700 nm) light, a major component of solar light exhibiting good atmosphere penetration, exploited by the natural PC chlorophyll a as well. Compared with ZnTPP, ZnTPTBP displayed a 49% increase in PET-RAFT polymerization rate with good control, marking a significant leap in the area of photo-controlled polymerization. [ABSTRACT FROM AUTHOR]

The absolute configuration of three chiral eugenol derivatives was assigned by a multi‐step methodology based on enantioselective HPLC combined with spectroscopic and theoretical calculations. Milligram amounts of enantiopure forms used for stereochemical characterization were isolated by HPLC on the immobilized amylose‐based chiral stationary phase Chiralpak IG using normal phase elution conditions. The absolute configuration was indirectly determined for one of the three compounds by 1H NMR via methoxy‐α‐trifluoromethyl‐α‐phenylacetic acid derivatization (Mosher's acid). Comparison of the experimental and predicted electronic circular dichroism spectra confirmed the stereochemical assignment by Mosher's method and extended the absolute configuration assignment to two other chiral compounds. [ABSTRACT FROM AUTHOR]

In this study, we present the synthesis of benzimidazo[1,2-a] quinoline-based heterocycles bearing organosulfur and organoselenium moieties through transition-metal-free cascade reactions involving a sequential intermolecular aromatic nucleophilic substitution (SNAr). Both sulfur and selenium derivatives presented absorption maxima located around 355 nm related to spin and symmetry allowing electronic 1π-π* transitions, and fluorescence emission at the violet-blue region (~440 nm) with relatively large Stokes shift. The fluorescence quantum yields were slightly influenced by the chalcogen, with the sulfur derivatives presenting higher values than the selenium analogs. In this sense, the quantum yields for selenium derivatives can probably be affected by the intersystem crossing or even the photoinduced electron transfer process (PET). The compounds were successfully applied in all-solution-processed organic light-emitting diodes (OLEDs), where poly(9-vinylcarbazole) was employed as a dispersive matrix generating single-layer device cells. The obtained electroluminescence spectra are a sum of benzimidazo[1,2-a]quinolines and PVK singlet and/or triplet emissive states, according to their respective energy band gaps. The best diode rendered a luminance of 25.4 cd⋅m−2 with CIE (0.17, 0.14) and current efficiency of 20.2 mcd⋅A−1, a fivefold improvement in comparison to the PVK device that was explained by a 50-fold increase of charge-carriers electrical mobility. [ABSTRACT FROM AUTHOR]