Fluorescence detection and adsorption of Zr4+ using pyrene incorporated mesoporous silica material.

The heterobimetallic M14 cluster [Co3Ga2]H(μ2-GaTMP)9 (1, TMP = 2,2,6,6-tetramethylpiperidinyl) was obtained by treating CoCl2 with GaTMP in the presence of Mg and H2 as reduction additives. 1 features a trigonal bipyramidal Co3Ga2 kernel with one substituent-free Ga atom and one exposed GaH moiety inside a metallo-environment of nine edge-bridging GaTMP ligands. The resulting Co3Ga11 cluster core mimics a packing motif of the structurally related intermetallic phase Co2Al5. The GaTMP ligands not only donate their lone pairs to the Co, but also to the exposed, bare Ga of the Co3Ga2 kernel, thus contributing to the increase in delocalization over the M14 core, according to bonding analysis. The synthesis of 1 represents proof-of-concept to steer the coordination of GaTMP to transition metal centers toward a kernel-alloyed Co/Ga cluster formation. This is rationalized by Mg/H2-induced Ga deprotection and TMP-trapping in the Hauser-base complex [Mg(TMP)(THF)μ2Cl]2. The method bears potential for generalization, and first results were obtained for related Fe/Ga clusters.

Propylene oxide is the first chiral molecule identified in the interstellar medium, which has resulted in growing interest in it as a prototypical molecule to study the origin of life on Earth. Numerous spectroscopic studies have investigated the excitation, ionization and dissociation of propylene oxide by photons, electrons and/or ions. However, for vacuum ultraviolet (VUV) photoabsorption spectroscopy, data are available only for energies between 6 and 9 eV with low energy resolution. Here, we present the high-resolution VUV photoabsorption cross-sections in the 6.0-10.8 eV range through an experimental and theoretical approach. The measurements were carried out using a VUV synchrotron radiation light source and are supported by quantum chemical calculations performed using time-dependent density functional theory. There is good agreement between experiment and theory, allowing us to characterize the main absorption bands assigned to electronic transitions involving mainly oxygen lone pairs and lower-lying Rydberg states. At higher energy, there are several Rydberg states observable, characterized by superimposed features with different vibrational progressions. Some features observed in the spectrum are assigned to vibrational modes involving the methyl group, namely CH3 bending (υ22 and υ23) and CH3 torsion (υ24). Additionally, we report a vibrational progression which may be related to the cation ring CC stretching with an average frequency of about 565 cm-1. Calculated potential energy curves for the low-lying excited states along the C-CH3 stretching coordinate reveal that the initial Rydberg states evolve into dissociative states at larger bond distances, as the σ* valence character increases.

This study aims to clarify the linear response excitation mechanisms and characteristics of the explosive 1-methyl-3,5-dinitro-1,2,4-triazole (MDNT) in the implicit solvent dimethyl sulfoxide (DMSO) when transitioning from the ground state to the 20 lowest-energy excited states. In the ground state MDNT molecule, there exists a steric hindrance effect within the triazole ring and between the nitro oxygen (O) and the azole ring nitrogen (N). Ahydrogen bond dominated by dispersion interaction is formed between the nitro O and the methyl hydrogen (H). Among the 20 low-energy excited states, S5, S7, S9, S10, S11, and S12 are significant bright states (with an oscillator strength of 0.01), and the remaining 14 are dark states (weakly allowed transitions, not observable in conventional UV-vis spectra). Note that this differs from the d-d transitions in transition metal complexes, where an f of 0.001 may still be weakly observable. The lifetimes of the six bright states are all in the nanosecond ranges (S10 is the longest, reaching 4.93 ns; S11 is the shortest, only 0.7 ns). S11 requires an excitation energy of 6.47 eV and corresponds to the maximum absorption peak. In terms of the excitation mechanism, S0 → S5/S7/S12 is a C-N π → N-O π charge transfer excitation (CT), S0 → S11 is a C-N π → N-O π local excitation (LE), and S0 → S9/S10 is a local excitation (LE) of the lonepair electrons n → N-O π* of the nitro O. This study provides a theoretical reference for the research on the electronic excitation mechanism and decomposition behavior of energetic materials. The Gaussian16 software is used for optimization and calculation, and the Multiwfn and VMD programs are applied for further processing and visualization. Using the time-dependent density functional theory (TDDFT) at the M06-2X/6-311G(d) level, the linear response electron excitation of MDNT in implicit solvent DMSO was investigated.

ABSTRACT The intrinsically low lattice thermal conductivity ( κ L ) caused by lone pair electrons makes I‐V‐VI 2 compounds promising candidates for thermoelectric applications. Elucidating the underlying mechanism of the correlation between lone pair electrons and defects plays an important role in providing critical insights for further designing low κ L materials. This work employs X‐ray pair distribution function analysis to probe the nanoscale local atomic structures of I‐V‐VI 2 compounds, using AgSbSe 2 as the model material to understand the structure‐property relationship. The stereochemically active lone pair electrons on Sb 3+ induce significant off‐centering displacements, introducing local symmetry breaking that can be systematically tuned through controlled vacancies, atomic disordering, or substitution. Theoretical calculations validate the connection between structural distortions and chemical bonding strength, resulting in the change of κ L . This work not only unveils the local structure evolution of AgSbSe 2 during alloying, but also provides a roadmap for performance optimization of I‐V‐VI 2 compounds with lone pair electron effects.

Can cation-π and cation-lone pair interaction stabilize alkali/alkaline earth metal ion-furan adducts? Acumen from DFT.

Intrinsic structural instability and nonradiative recombination limit the long-term performance of formamidinium lead iodide (FAPbI3). Using ab initio nonadiabatic molecular dynamics, we identify a novel FA dimerization mechanism and its impact on structural stability and carrier dynamics. FA dimerization proceeds via a self-interstitial mechanism and formation of noncovalent parallel dimers within a single A-site cavity. This configuration strengthens hydrogen bonding with surrounding [PbI6]4- octahedra, promotes octahedral tilting, suppresses low-frequency Pb-I vibrations, and reduces nonadiabatic coupling, resulting in ∼50% longer carrier lifetimes relative to that of the nondimerized system. In contrast, FA deprotonation generates deep trap states that dramatically accelerate nonradiative recombination. Importantly, FA dimerization in defective lattices activates nitrogen lone pairs, inducing C-C covalent and N-Pb coordination bonding. These interactions eliminate midgap states, restore hydrogen bonding, suppress dynamic disorder, and reestablish long carrier lifetimes. Together, these results establish FA dimerization as an intrinsic stabilization and defect-passivation mechanism in perovskite optoelectronic materials.

Exploring the potential of calcium-chelating peptides from aquatic sources: Structure-activity relationship, computational simulation, and stability mechanism analysis.

Synthesis, characterization, and anticancer activity of acylthiourea-ruthenium(II) p-cymene complexes.

We report the synthesis and characterization of a T-shaped, 8-electron stannyliumylidene ion bearing a rigid acridane-based pincer ligand. This cationic Sn(II) complex exhibits pronounced ambiphilic reactivity, participating in electrophilic, nucleophilic, and σ-bond activation reactions. All derived compounds were characterized by nuclear magnetic resonance spectroscopy, single crystal x-ray diffraction analysis, and high-resolution mass spectrometry. Density functional theory calculations reveal the coexistence of a lone pair of electrons and a vacant 5p-orbital at the tin center, which rationalizes the experimentally observed dual reactivity. Remarkably, the transition metal-like electronic structure enables this organotin(II) species to act as an efficient catalyst for transfer hydrogenation of azoarenes and imines using NH3BH3 as hydrogen source. Combined experimental and computational mechanistic studies reveal a distinct catalytic platform based on Sn(II)/Sn(IV) redox cycle at a single tin(II) center. This work demonstrates the first Sn(II)/Sn(IV) catalyzed reduction of unsaturated bonds, offering a paradigm for mimicking transition metal reactivity through rationally designed main group systems in mediating diverse chemical transformations.

Molybdenum tellurite compounds have attracted increasing interest as promising nonlinear optical (NLO) materials, yet their microscopic second-harmonic generation (SHG) mechanisms remain unclear. In this work, the electronic structures and SHG responses of ATeMoO6 (ATM, A = Mg, Cd, Zn) are systematically investigated using first-principles calculations combined with atom response theory. The results show that the SHG responses are mainly governed by the occupied nonbonding O 2p states and the unoccupied Mo 4d and Te 5p states. Our atom response theory analysis reveals that a strong synergistic effect between stereochemically active lone pairs (SCALPs) on Te atoms and nonbonding O 2p states critically enhances the SHG response in ZnTM and MgTM. In contrast, the relative weaker Te SCALPs in CdTM fail to provide a comparable contribution, leading to its lower SHG performance. The structure group analysis reveals that MoO4 units dominate the SHG response, while TeO4 units provide secondary contributions. Moreover, group dipole moments are found to be insufficient to explain the SHG behavior. These findings provide microscopic insights into SHG origins and offer guidance for NLO material design.

Electrochemical advanced oxidation processes are promising for perfluorooctanoic acid (PFOA) degradation; however, strategies for enhancing degradation performance through rational regulation of the reaction medium remain insufficiently understood. In this study, systematic screening of nitrogen-containing compounds showed that discrete inorganic nitrogen species (e.g., ammonium and nitrate) failed to induce any measurable degradation or defluorination of PFOA. In contrast, nitrogen-containing compounds with lone-pair electrons (e.g., glycine and nitrilotriacetic acid) acted as effective promoters, enabling a maximum PFOA removal efficiency of 88.4% within 300 min. Using glycine as a representative additive, mechanistic investigations demonstrated that cooperative coordination among glycine, PFOA, and the Pt electrode surface promotes anodic direct electron transfer. In parallel, glycine-assisted electrochemical processes generate reactive oxidizing species, particularly reactive nitrogen species (e.g., •NO3) and hydroxyl radicals (•OH), which contribute to indirect oxidation pathways. These two processes act synergistically to govern the PFOA degradation. Fluorine mass balance analysis further revealed that stepwise defluorination via CnF2n+1• and COF2 formation dominated mineralization, accounting for 85.4-97.9% of fluorine release, whereas short-chain intermediates constituted only a minor route. Overall, this study elucidates the coupled roles of interfacial coordination regulation and reactive nitrogen chemistry in electrochemical PFAS degradation, providing mechanistic guidance for effective electrochemical treatment systems.

Rashba-Dresselhaus (RD) spin splitting arising from spin-orbit coupling in spatial inversion asymmetric semiconductors is critical for realizing numerous advanced spintronic applications. However, modulating the RD spin splitting coefficient (αRD) is challenging due to the unclear structural-property relationship. Herein, inspired by highly distorted inorganic selenites containing stereochemically active lone pair (SCALP) electrons, we selected 4-aminomorpholine cation (4AM) containing SCALP electrons to synthesize a new two-dimensional (2D) ferroelectric semiconductor (4AM)2PbBr4, exhibiting a giant αRD of 2.377eVÅ with ΔERD = 126 meV and Δk0 = 0.106Å-1 that differentiates circularly polarized light-excited carriers in the momentum space via spin-dependent optical transition selection rules with an asymmetric factor of 0.65. A geometric structure-property relationship study reveals that incorporating SCALP into the organic cations enhances their net polarity and induces substantial distortions within the inorganic sublattices that enhance the αRD. This work reveals the regulatory mechanism of organic cations on distortion of inorganic octahedron and provides a new approach for efficient synthesis and rapid screening of 2D ferroelectric semiconductors with large αRD.

Polar Hybrid Perovskite Obtained by Induction of Lone Pair Electrons toward Efficient and Stable Self-Powered X-ray Detection

Abstract Two-dimensional (2D) materials have been widely studied across materials science, physics, and chemistry. Investigating the thermal transport properties of 2D materials is of great significance for applications in thermal management. In this paper, based on first-principles calculations, we conducted a systematic study on the impact of strain on the thermal conductivities of penta -AlN 2 and h -AlN. Under tensile strain, the thermal conductivities of h -AlN and penta -AlN 2 show clear contrasts. The h -AlN exhibits non-monotonic behavior with a peak at 3% strain, while penta -AlN 2 shows non-monotonic variation first decreasing then increasing and forms a valley at 1% strain. Additionally, the thermal conductivity of penta -AlN 2 is one order of magnitude lower than that of h -AlN. The underlying mechanisms is distinctly different. The h -AlN’s non-monotonicity comes from non-monotonic phonon relaxation time under strain. For penta -AlN 2 , increasing strain first strengthens the coupling between lone-pair electrons and bonding electrons, which reduces phonon relaxation time and lowers thermal conductivity. When strain ranges from 2% to 4%, this coupling weakens, and the reduced relaxation time is no longer sufficient to offset increased phonon group velocity, leading to higher thermal conductivity. Moreover, the lower thermal conductivity of penta -AlN 2 is mainly due to its low lattice symmetry, which induces strong phonon scattering and shortens phonon relaxation time. The findings highlight the crucial roles of lone-pair electrons and lattice structures in strain-engineered thermal conductivity. Meanwhile, investigating the response of thermal conductivity to strain holds significant value for engineering applications in thermal management and electronic devices.

The environmental persistence of per- and polyfluoroalkyl substances (PFASs), driven by the exceptional stability of their C-F bonds, presents a formidable challenge for remediation. Herein, we report the 5,10,15,20-tetraphenyl (4-aminophenyl) porphyrin (TAPP) aggregates as visible-light-driven photocatalysts capable of achieving almost-100% defluorination of PFASs without chemical additives. Central to this process is the ultra-stable TAPP radical species (TAPP•), which exhibits a lifetime exceeding 7 days under ambient conditions. Under visible-light irradiation, TAPP• generates reductive electrons with a potential of -2.68 VNHE, enabling injection into the C-F antibonding orbitals to initiate defluorination. The exceptional stability of TAPP• arises from intramolecular charge delocalization mediated by the synergistic overlap between the lone-pair electrons distribution of the amino groups and the highest occupied molecular orbital. This work develops a steady radical strategy that leverages charge-delocalization to engineer photocatalysts with highly reductive electron, offering an approach to address persistent environmental contaminants.

Planar hexacoordinate atoms are challenging to achieve. The first planar hexacoordinate sulfur and selenium (phS/Se) X©Li6H62- (X = S, Se) clusters were predicted. High-level quantitative calculations reveal that the global minima of X©Li6H62- (X = S, Se) adopt singlet D6h-symmetric structures, each consisting of a central S/Se atom coordinated by a Li6 hexagon, with every Li-Li edge further capped by an H atom. Born-Oppenheimer molecular dynamics simulations confirm that the phX structures of X©Li6H62- (X = S, Se) are robust. Furthermore, bonding analyses reveal that there is one lone pair for the central S2-/Se2-, three delocalized σ bonds within the S©Li6/Se©Li6 core, and six delocalized 3c-2e σ bonds along the periphery. Energy decomposition analysis-natural orbitals for chemical valence analysis-indicates that electrostatic interactions dominate between phS/Se and the Li6H6 ring, with a contribution rate of 75.8% and 75.6%. The stability of the phS/Se center is dominated by multicenter ionic bonds. The current results not only break the conventional coordination limit for chalcogen elements but also motivate further theoretical and experimental studies on novel phS/phSe complexes.

Low-dimensional hybrid metal halides (LDMHs) exhibit markedly distinctive optoelectronic properties due to their unique quantum effects and strong exciton binding energies. Given the pressing need to accelerate research on the design of optoelectronic materials and their device integration, it is imperative to investigate the correlation between the structural properties of LDMHs and the underlying photophysical mechanisms responsible for their unique luminescent characteristics. In this work, we realize a 40-fold pressure-induced photoluminescence (PL) emission increase in the zero-dimensional (0D) compound [TPPen]2SbBr5 (TPPen = triphenylpentylphosphonium) and more notably the PL intensity is further enhanced upon pressure release. In situ characterizations and theoretical calculations indicate that pressure promotes lone pair-π (LP-π) interactions between Sb3+ lone-pair electrons and the π-electrons of the phenyl rings, thereby enabling more efficient charge transfer (CT) across the organic–inorganic interface, leading to significantly enhanced PL intensity. The irreversible structural distortion and lattice disruption caused reservation of pressure-induced emission enhancement. This study offers an effective strategy for facilitating CT between organic ligands and inorganic polyhedra and provides insights into pressure-induced emission phenomena in 0D hybrid metal halides.

Lithium–sulfur (Li–S) batteries suffer from the infamous lithium polysulfides (LPSs) shuttle effect, which generates reduced utilization of active materials and polysulfide‐corrosion‐accelerated lithium dendrite, ultimately resulting in poor capacity and cycling stability. While various natural clays have demonstrated effective adsorption for LPSs, there is no consensus on the adsorption mechanisms and active sites. Inspired by the distinct acid–base chemistry of clay basal and edge surfaces, we designed a capsule‐shaped silicate clay (H‐ATP‐N 2 ) that is rich in protonated edge hydroxyl groups (‐OH 2+ ). The synthesis involved a two‐step process: first, microwave‐assisted acid treatment was used to efficiently activate the surface of fibrous attapulgite. Next, N 2 plasma etching was applied to further enrich the material with the ‐OH 2 + . These specific methods were chosen to optimize the activation and functionalization of attapulgite, enhancing its ability to serve as a highly effective polysulfide‐trapping interface for improved electrochemical energy storage. Compared with the surface hydroxyl sites, the ‐OH 2 + act as Lewis acid sites to accept lone electron pairs from LPSs, thereby exhibiting a stronger interaction to successfully inhibit the shuttle effect. With the protonated edge hydroxyl groups in attapulgite dominating LPSs adsorption via a Lewis acid–base adsorption mechanism, the H‐ATP‐N 2 cathodes deliver a 1139.9 mAh g −1 capacity at 0.1 C, and a reversible capacity of 808.6 mAh g −1 after 500 cycles at 0.5 C with an ultralow capacity decay rate of 0.04% per cycle, which have surpassed the vast majority of reported clay‐based cathodes.

The design and synthesis of outstanding nonlinear optical (NLO) crystals continue to represent a pivotal challenge in advanced laser technologies. Herein, two new zero-dimensional (0D) organic-inorganic hybrid antimony halides, C4H9N5SbX5·H2O (X = Cl, Br) featuring [SbX5] square pyramids, were successfully synthesized by three-in-one integrating a Sb3+ ion with a stereochemically active lone pair (SCALP), π-conjugated organic (C4H9N5)2+ cation, and halide anion. They adopt trigonal noncentrosymmetric (NCS) space groups P32 and P31, respectively. Both exhibit outstanding comprehensive NLO properties, featuring phase-matchable second-harmonic generation (SHG) intensities around 3.8 and 3.9 times that of KDP, respectively, broad optical bandgaps of 3.17 and 2.68 eV, and adequate birefringence of 0.12 and 0.10 at 546 nm, demonstrating their significant potential as nonlinear optical materials. Theoretical studies and structural analyses reveal that their excellent optical properties originate from the synergistic effect of organic cations and inorganic [SbX5] square pyramids. This work establishes a rational design framework for guiding the development of advanced NLO crystals.