Exploring chemical reactivity through a combined conceptual DFT and ELF topology approach.

CONTEXT: In a proof-of-concept study, we explore how a combined approach using the topology of the electron localization function (ELF) and the condensed dual descriptor (DD) function can guide the optimal orientation between reactants and mimic the potential energy surfaces of molecular systems at the beginning of the chemical pathway. The DD has been chosen for its ability to evaluate the regioselectivity of neutral and soft species and to potentially mimic the interaction energy obtained from the mutual interactions between nucleophilic and electrophilic regions of the building blocks under perturbative theory. METHOD: Our method has been illustrated with examples in which the optimal orientation of several systems can be successfully identified. The limitations of the presented model in predicting chemical reactivity are outlined in particular the influence of the selected condensation scheme.

Electrochemically Gated Frustrated Lewis Pair Chemistry in Electric Double Layer.

The recent discovery of frustrated Lewis pairs (FLPs) during the activation of small molecules has inspired extensive research across the full span of chemical science. Owing to the nature of weak interactions, it is experimentally challenging to directly observe and modulate FLP at the molecular scale. Here we design a boron cluster anion building block (B10H82-) and organic amine cations ([NR4]+, R= -CH3, -C2H5) as the FLP to prove the feasibility of controlling their interaction in the electric double layer (EDL) via an electrochemical strategy. In situ single-molecule electrical measurements and Raman monitoring of B10H82--[NR4]+ FLP formed at the positively charged Au(111) electrode surface, in contrast to the free-standing B10H82- near or below the potential of zero charge (PZC). Furthermore, this FLP chemistry leads to a shift in the local density of states of boron clusters towards the EF for enhancing electron transport, providing a new prototype of a reversible single-cluster switch that digitally switches upon controlling FLP chemistry in the electric double layer.

Preparation, structure, reactivity, Lewis acidic and fluorescence properties of arylpyridine based boron C,N-chelates featuring weakly coordinating anions.

Herein, we present the preparation of a series of electronically and/or sterically distinct borenium-type species based on a simple 2-arylpyridine scaffold. Corresponding arylpyridine was firstly subjected to electrophilic borylation (BBr3 / i-Pr2NEt) and formed BBr2 chelate was reduced with LiAlH4 to yield arylpyridine boron dihydride. Elimination of one hydride led to Lewis acidic borenium-like products. Four methods of hydride elimination were evaluated and influence of counterions on reactivity, Lewis acidic and luminescent properties was assessed both experimentally and computationally. Arylpyridine chelates featuring weakly coordinating counterions exhibit fluorescent properties upon UV irradiation. Several general trends were inferred to modulate emission wavelength and fluorescence quantum yield. Based on our observations, we have devised and prepared borenium-type fluorophores with yellow-green fluorescence and quantum yields up to 93%.

Frustrated Lewis Pair Mediated f-p-d Orbital Coupling: Achieving Selective Seawater Oxidation and Breaking *OH and *OOH Scaling Relationship.

The development of materials for hydrogen production via seawater electrolysis at high current densities plays a crucial role in producing renewable hydrogen energy. However, during the seawater electrolysis process, the anode inevitably undergoes chloride oxidation reaction (ClOR) due to Cl- adsorption, making the seawater electrolysis process difficult to sustain. Inspired by the selective permeability of cell membranes, we propose a biomimetic design of frustrated Lewis pairs (FLPs) layers. Combining experimental results and molecular dynamics simulations, it has been demonstrated that cerium dioxide layers with FLPs sites can decompose water molecules, capture hydroxyl anions, and repel chloride ions simultaneously. DFT theoretical analysis indicates that the FLP sites regulate the Ce 4f-O 2p-Ni 3d gradient orbital coupling, providing additional oxygen non-bonding (ONB) to stabilize the Ni-O bond and optimize the adsorption strength of intermediates, thereby breaking the *OH and *OOH scaling relationship. Assembled anion exchange membrane electrolyzers exhibit an efficiency of 95.7% at a current density of 0.1 A cm-2 and can stably operate for 250 hours at a current density of 0.2 A cm-2.

Friedel-Crafts Reactivity with Sulfondiimidoyl Fluorides for the Synthesis of Heteroaryl Sulfondiimines.

Sulfur functional groups are ubiquitous in molecules used in the pharmaceutical and agrochemical industries, and within these collections sulfones hold a prominent position. The double aza-analogues of sulfones, sulfondiimines, offer significant potential in discovery chemistry but to date their applications have been limited by the lack of convenient synthetic routes. The existing methods mainly rely on imination of low-valent-sulfur intermediates, or the combination of pre-formed organometallic reagents and electrophilic S(VI)-functionalities. Herein, we describe a Friedel-Crafts-type reaction of sulfondiimidoyl fluorides with (hetero)aryls. This new SuFEx reactivity benefits from broad functional group tolerance, mild reaction conditions, and does not require the use of pre-formed organometallic reagents. The efficient use of unprotected indoles and pyrroles, as well as furan, thiophene and carbocyclic aromatics, further demonstrates the advantages of these reactions. We show that the reactivity of the sulfondiimidoyl fluorides can be tuned by switching the N-substituents, allowing an expansion of the range of coupling partners. The utility of the transformation is exemplified by the synthesis of the sulfondiimine analogue of the HIV-I reverse transcriptase-inhibitor L-737,126.

Improved surface acidity of CeO2/TiO2 catalyst by Cu doping to enhance the SCR catalytic activity.

The catalyst is based on CeO2 cannot be widely used in SCR reaction because of its poor NH3 adsorption performance. In this study, Cu-doped CeTi catalyst was designed. The results show that the CeTiCu0.3 has a wide active temperature window of 200-450 °C in NH3-SCR reaction, and NO conversion is > 80%. This is mainly due to the fact that Cu doping provides more acidic sites on the surface of CeTi catalyst, especially the increase of Lewis acid sites is more obvious. NH3-TPD showed that CeTiCu0.3 had a large NH3 adsorption capacity and was mainly adsorbed at Lewis acid sites. In situ DRIFTs results show that NH3 first adsorbs on the Lewis acid site of catalyst in coordination state and reacts with gaseous NOx, while NOx adsorbed on catalyst surface has low reactivity. Therefore, the CeTiCu0.3 catalyst is mainly controlled by the Eley-Rideal mechanism. More Lewis acid sites, and abunda nt Cu2+/Cu+ and Ce4+/Ce3+ formed Cu2+, Ce3+ and surface reactive oxygen species are the main reasons for the excellent catalytic performance of CeTiCu.

Interface engineering enhances Lewis acidity and activates inert sites to jointly promote nitrate reduction to ammonia.

Electrocatalytic nitrate reduction to ammonia (NRA) has been considered a highly promising method for "waste to treasure". Herein, a heterogeneous catalyst FeP/Cu3P/CF enriched with Lewis acid sites was designed for efficient NRA. The faradaic efficiency and NH3 yield are up to 95.61 % and 0.2573 mmol h-1 cm-2, the NH3-N selectivity is 95.11 %, and the NO3--N conversion is close to 100 %. Experimental and theoretical studies verify that the formation of the interface activates the originally inert Fe site and makes it become the second active center in addition to Cu. The charge transfer greatly raises the positive charge density of Feδ+ and Cuδ+ sites, leading to a significant increase in their Lewis acidity, which enables them to interact strongly with the Lewis base NO3- and improves the NRA performance; meanwhile, the ability of P site with increased negative charge density to capture H enhances, which is beneficial for the subsequent hydrogenation of nitrate reduction. This work provides an approach for designing efficient NRA catalysts through interface engineering strategy.

Overexpression of sialyl lewisa carrying mucin-type glycoprotein in prostate cancer cell line contributes to aggressiveness and metastasis.

Metastasis-promoting Lewis and sialyl Lewis antigens expressed on glycoproteins such as mucins are frequently displayed on the surface of prostate cancer cells and could thus be ideal candidates as measures of prostate cancer aggressiveness. The current study describes the altered expression of sialyl Lewisa (sLea) antigen attached to glycoproteins and key glycosyltransferases between normal prostate (RWPE-1) and cancerous cell lines (LNCaP and DU145). Our results suggest that the expression of sLea on different glycoproteins correlates with the aggressiveness of prostate cancer cells, as determined by flow cytometry and fluorescence microscopy. Blotting studies revealed that sLea-bearing glycoproteins, similar to mucins, are predominantly expressed in the more aggressive DU145 cells, followed by LNCaP cells. Immunohistochemistry technique showed a gradient of sLea expression, with low levels in low-grade prostate cancer (stage II/III) and increasing levels in high-grade cancer (stage IV), indicating its potential as a prognostic marker. Additionally, in qRT-PCR analysis significant upregulation of the glycosyltransferases GALNT5 and ST3GAL6 was observed, correlating with the increased sLea expression in LNCaP (3.2- and 14.5-fold) and DU145 (3.3- and 23.75-fold) cells. Our data indicates a correlation between sLea selectin ligand expression and prostate cancer aggressiveness. Furthermore, GALNT5 and ST3GAL6 could serve as benchmarks in PCa malignancy.

Hydroxyl Defects-Mediated Hydrolytic Activation of Peroxydisulfate Under Nanoconfinement: Role of Lewis Basic Sites for Altering the Photosensitized Species and Pathways.

Herein, the pivotal mechanism of defect engineering-mediated triazine-based conjugated polymers (TCPs) is comprehensively elucidated for photosensitized activation of peroxydisulfate (PDS) under nanoconfinement by encapsulating the defective polymer framework into the nanochannel of SBA-15 (d-TCPs@SBA-15). The incorporated hydroxyl defects (-OH defects) substantially accelerate the accumulation of electrons at -OH defects, forming the Lewis basic sites. Due to the facilitated elongation of the S─O bond and reduced energy barrier of SO5* generation, the captured PDS undergo prehydrolysis process, oxidized into O2 - and 1O2 by surrounding h+, thereby setting apart from the conventional reductive activation of SO4 -/•OH generation occurred in pristine TCPs (p-TCPs). Crucially, this work represents a pioneering effort in exploring the PDS activation pathway upon the defective polymer under the nanoconfinement to leverage kinetic merits of slow photon effect and reactive oxygen species (ROSs) enrichment, and the novel prehydrolysis activation mechanism involved may catalyze the rational design of photocatalysts featuring Lewis-acid/base centers.

Strikingly Facile Cleavage of N-H/N-O Bonds Induced by Surface Frustrated Lewis Pair on CeO2(110) to Boost NO Reduction by NH3.

Ceria with surface solid frustrated Lewis pairs (FLPs), formed by regulating oxygen vacancies, demonstrate remarkable ability in activating small molecules. In this work, we extended the application of FLPs on CeO2(110) to the selective catalytic reduction of NO by NH3 (NH3-SCR), finding a notable enhancement in performance compared to ordinary CeO2(110). Additionally, an innovative approach involving H2 treatment was discovered to increase the number of FLPs, thereby further boosting the NH3-SCR efficiency. Typically, NH3-SCR on regular CeO2 follows the Eley-Rideal (E-R) mechanism. However, density functional theory (DFT) calculations revealed a significant reduction in the energy barriers for the activation of N-O and N-H bonds under the Langmuir-Hinshelwood (L-H) mechanism with FLPs present. This transition shifted the reaction mechanism from the E-R pathway on regular R-CeO2 to the L-H pathway on FLP-rich FR-CeO2, as corroborated by the experimental findings. The practical application of FLPs was realized by loading MoO3 onto FLP-rich FR-CeO2, leveraging the synergistic effects of acidic sites and FLPs. This study provides profound insights into how FLPs facilitate N-H/N-O bond activation in small molecules, such as NH3 and NO, offering a new paradigm for catalyst design based on catalytic mechanism research.

Syntheses of Novel Spirobenzazepinoindole Derivatives via Lewis-Acid Catalyzed Pictet-Spengler Cyclization.

The synthesis of novel spirobenzazepinoindole derivatives has been achieved through a highly efficient and synthetic route. The approach involves a two-step reaction, utilizing indole derivatives, 2-amino benzyl alcohol, and ninhydrin as key starting materials under mild reaction conditions. The reaction proceeds via a sequential cascade process involving cyclization, condensation and spiro-annulation, leading to the formation of the spirobenzazepinoindole core structure in good to excellent yields. The method offers broad substrate scope, high atom economy, and operational simplicity. The synthesized spirobenzazepinoindoles were fully characterized by spectroscopic techniques, including NMR (1H & 13C), IR and mass spectrometry. The methodology provides a valuable tool for the rapid generation of structurally complex spirobenzazepinoindoles, which could serve as scaffolds for the development of new therapeutic agents.

Facile heterolytic bond splitting of molecular chlorine upon reactions with Lewis bases: Comparison with ICl and I2.

Formation of molecular complexes and subsequent heterolytic halogen-halogen bond splitting upon reactions of molecular Cl2 with nitrogen-containing Lewis bases (LB) are computationally studied at M06-2X/def2-TZVPD and for selected compounds at CCSD(T)/aug-cc-pvtz//CCSD/aug-cc-pvtz levels of theory. Obtained results are compared with data for ICl and I2 molecules. Reaction pathways indicate, that in case of Cl2∙LB complexes the activation energies for the heterolytic Cl-Cl bond splitting are lower than the activation energies of the homolytic splitting of Cl2 molecule into chlorine radicals. The heterolytic halogen splitting of molecular complexes of X2∙Py with formation of [XPy2]+… X 3 - $$ {\mathrm{X}}_3^{-} $$ contact ion pairs in the gas phase is slightly endothermic in case of Cl2 and I2, but slightly exothermic in the case of ICl. Formation of {[ClPy2]+… Cl 3 - $$ {\mathrm{Cl}}_3^{-} $$ }2 dimers makes the overall process exothermic. Taking into account that polar solvents favor ionic species, generation of donor-stabilized Cl+ in the presence of the Lewis bases is expected to be favorable. Thus, in polar solvents the oxidation pathway via donor-stabilized Cl+ species is viable alternative to the homolytic Cl-Cl bond breaking.

Evaluating the effectiveness of citation count as a measure of methodological quality in esophagogastric surgery research: a comparative analysis with the MINORS score and levels of evidence.

Aim: The primary objective was to assess the relationship between the citation number and the quality of the articles, as compared with the level of evidence and the MINORS score. This study's secondary objective was to characterize the 50 most cited articles in the field of oesophagectomy research. Background: There has been an increased need for an evaluation tool to indicate research quality. Available quality assessment tools include the Level of Evidence, the MINORS score, the Cochrane Risk of Bias 2.0 Tool, the Newcastle Ottawa Scale, CASP Appraisal Checklists, and Legend Evidence Evaluation tools. Methods: The Web of Science allowed evaluating and comparing articles on oesophagectomy research. The quality of the 50 most cited articles was assessed using the Oxford Centre level of evidence classification and the methodological index for non-randomized studies (MINORS). Results: Level of evidence II studies were cited more than level IV (P=0.008). There was a significant positive correlation between citation number and MINORS score (P=0.002). The median MINORS score was highest amongst level II studies, followed by levels III, IV, and I. The median MINORS score for level II evidence was significantly higher than for level IV (P=0.001). The study sample size is associated with higher levels of evidence but does not correlate with the citation number. Female authors contributed to 4 out of 50 articles. Recently published articles tended to be cited more frequently. More authors equated to more citations. Prospective studies are more likely to be cited. Conclusion: Citation analysis can be used as an indicator of quality when assessing articles. It should, however, be used with caution as highly cited work, famous authors, and journals are all more likely to be cited. Citation analysis should be used alongside other well-established tools.

A Rare Example of a Gallium-based Lewis Superacid: Synthesis and Reactivity of Ga(OTeF5)3.

The Lewis superacid Ga(OTeF5)3 has been synthesized and characterized, revealing a monomeric structure in solution and a dimeric structure in the solid state. Isolated adducts of Ga(OTeF5)3 with strong and weak Lewis bases have been characterized spectroscopically as well as single-crystal X-ray diffractometry. The Lewis acidity of this new species has been evaluated by means of different experimental and theoretical methods, which has allowed to classify it as one of only a few examples of a gallium-based Lewis superacid. The high Lewis acidity of Ga(OTeF5)3 was used to amplify the strength of the Brønsted acid HOTeF5, leading to the protonation of diethyl ether. Furthermore, Ga(OTeF5)3 was utilized to access the strong oxidizing system Ga(OTeF5)3/Xe(OTeF5)2 in SO2ClF, which was successfully employed in the synthesis of the dimethyl chloronium salt [Cl(CH3)2][Ga(OTeF5)4], a strong electrophilic methylation reagent.

The role of linkers and frustrated lewis pairs catalysts in the formation of zwitterionic 1,2-anti-addition product with non-conjugated terminal diacetylenes: A computational study.

This study presents a computational investigation into the mechanistic pathway and the linker units involved in forming the zwitterionic 1,2-anti-addition product of non-conjugated diacetylenes, di(propargyl)ether (DPE), di(prop-2yn-1yl)sulfane (DPS) and 1,6-Heptadiyne (HD) catalyzed by the inter-molecular phosphine/borane frustrated Lewis pairs (FLPs), i.e., PPh2[C6H3(CF3)2](P-CF)/[B(C6F5)3]([B]) and P(o-tolyl)3(P-tol)/[B(C6F5)3]([B]). The potential energy surface (PES) calculations reveal that the anti-addition of P-CF to the internal C-atoms of acetylene units is energetically more favored than that of the addition of P-tol in DPE, DPS, and HD by ∼10.0, ∼9.2, and ∼6.0 kcal/mol, respectively. The calculations performed with DPE contain "-O-," linker unit exhibits superior reactivity than DPS and HD, which suggests the electronegativity of linkers plays a significant role and facilitates the addition of Lewis bases. The higher electronegativity of linker units enables the 1,2-addition reaction by lowering the free energy activation barriers, as observed in the DFT calculations. The Molecular Electrostatic Potential (MESP) study shows that the electrostatic interactions favor the addition of P-CF to the active acetylene positions (C5/C4/C4) of [B]-DPE/DPS/HD-π complexes than the P-tol. The Distortion/Interaction (D/I) analysis reveals that transition states involving P-CF (TS1, TS3, and TS5) exhibit more interaction energy (ΔEInt) and less distortion energies (ΔEd) than that of the P-tol (TS2, TS4, and TS6). Further, the Energy Decomposition Analysis (EDA) also rationalizes the preferential approach of the electron-deficient Lewis base over the electron-rich one on the basis of the significant contribution of orbital interaction energies (ΔEorbital) in the cases of P-CF; TS1, TS3, and TS5. This study suggests that the electronic effects of substrates and the FLPs are crucial to facilitate the desired products formed with non-conjugated terminal alkynes.

Chlorodefluorination Induced by Gallium-Based Lewis Acids.

The reaction of [Ga(C2F5)3(FSiMe3)] with chlorotrimethylsilane leads to the selective substitution of the α-fluorine atoms by chlorine atoms and thus to the formation of [Ga(CCl2CF3)3(FSiMe3)]. The corresponding chlorogallate ion, [Ga(CCl2CF3)3Cl]-, could be isolated and structurally characterized as its tetraphenylphosphonium salt. The catalytic potential of [Ga(CCl2CF3)3(FSiMe3)] was demonstrated via the chlorodefluorination of Me3SiCF3, 2,2-difluoropropane and [PPh4][Ga(C2F5)4].

The Reactivity of Ptn + Clusters With N2O Facilitated by Dual Lewis-Acid Sites.

The size dependence of metal cluster reactions frequently reveals valuable information on the mechanism of nanometal catalysis. Here, the reactivity of the Ptn + (n = 1-40) clusters with N2O is studied and a significant dependence on the size of these clusters is noticed. Interestingly, the small Ptn + clusters like Pt3 + and Pt4 + are inclined to form N2O complexes; some larger clusters, such as Pt19 +, Pt21 +, and Pt23 +, appear to be unreactive; however, the others such as Pt3 , 9,15 + and Pt18 + are capable of decomposing N2O. While Pt9 + rapidly reacts with N2O to form a stable quasitetrahedron Pt9O+ product, Pt18 + experiences a series of N2O decompositions to produce Pt18O1-7 +. Utilizing high-precision theoretical calculations, it is shown how the atomic structures and active sites of Ptn + clusters play a vital role in determining their reactivity. Cooperative dual Lewis-acid sites (CDLAS) can be achieved on specific metal clusters like Pt18 +, rendering accelerated N2O decomposition via both N- and O-bonding on the neighboring Pt atoms. The influence of CDLAS on the size-dependent reaction of Pt clusters with N2O is illustrated, offering insights into cluster catalysis in reactions that include the donation of electron pairs.

Thoracoscopic three-port single versus multiple intercostal for radical resection of esophageal cancer: a retrospective analysis.

BACKGROUND: The purpose of this retrospective study was to compare the safety and feasibility of single-intercostal totally minimally invasive Ivor Lewis esophagectomy (MIIE) with those of multiple-intercostal MIIE. METHODS: Between January 2016 and December 2022, clinical data were collected for 528 patients who successfully underwent totally minimally invasive esophagectomy. Among these patients, 294 underwent MIIE, with 200 undergoing the single-intercostal approach and 94 undergoing the multiple-intercostal approach. Propensity score matching (PSM) was applied to the cohort of 294 patients. Subsequently, perioperative outcomes and other pertinent clinical data were analyzed retrospectively. RESULTS: A total of 294 patients were subjected to PSM, and 89 groups of patient data (178 persons in total) were well balanced and included in the follow-up statistics. Compared to the multiple intercostal group, the single intercostal group had a shorter operative time (280 min vs. 310 min; p < 0.05). Moreover, there was no significant difference in the incidence of major perioperative complications (p > 0.05). The total number of lymph nodes sampled (25.30 vs. 27.55, p > 0.05) and recurrent laryngeal nerve lymph nodes sampled on the both sides (p > 0.05) did not significantly differ. The single intercostal group had lower postoperative long-term usage of morphine (0,0-60 vs. 20,20-130; p < 0.01), total temporary addition (10,0-30 vs. 20,20-40; p < 0.01) and temporary usage in the first 3 days after surgery (0,0-15 vs. 10,10-20; p < 0.01) than did the multicostal group.There were no significant differences in age, sex, tumor location or extent of lymphadenectomy or in the clinical factors between the single-intercostal group (p > 0.05). CONCLUSIONS: Both techniques can be used for the treatment of esophageal cancer. Compared to multiple intercostal MIIE, the feasibility of which has been proven internationally, the single intercostal technique can also be applied to patients of different age groups and sexes and with different tumor locations. It can provide surgeons with an additional surgical option. TRIAL REGISTRATION: This study was retrospectively registered by the Ethics Committee of the Second Affiliated Hospital of Zhejiang University School of Medicine, and written informed consent was exempted from ethical review. The registration number was 20,230,326. The date of registration was 2023.03.26.

Illuminating the Performance of Electron Withdrawing Groups in Halogen Bonding.

Throughout the halogen bonding literature, electron withdrawing groups are relied upon heavily for tuning the in- teraction strength between the halogen bond donor and acceptor; however, the interplay of electronic effects associated with various substituents is less of a focus. This work utilizes computational techniques to study the degree of σ- and π- electron donating/accepting character of electron withdrawing groups in a prescribed set of halo-alkyne, halo-benzene, and halo-ethynyl benzene halogen bond donors. We examine how these factors affect the σ-hole magnitude of the donors as well as the binding strength of the corresponding complexes with an ammonia acceptor. Statistical analyses aid the interpretation of how these substituents influence the properties of the halogen bond donors and complexes, and show that the electron withdrawing groups that are both σ- and π-electron accepting form the strongest halogen bond complexes.

Secondary Sphere Lewis Acid Activated Heme Superoxo Adducts Mimic Crucial Non-Covalent Interactions in IDO/TDO Heme Dioxygenases.

Heme enzymes play a central role in a medley of reactivities within a wide variety of crucial biological systems. Their active sites are highly decorated with pivotal evolutionarily optimized non-covalent interactions that precisely choreograph their biological functionalities with specific regio-, stereo-, and chemo-selectivities. Gaining a clear comprehension of how such weak interactions within the active sites control reactivity offers powerful information to be implemented into the design of future therapeutic agents that target these heme enzymes. To shed light on such critical details pertaining to tryptophan dioxygenating heme enzymes, this study investigates the indole dioxygenation reactivities of Lewis acid-activated heme superoxo model systems, wherein an unprecedented kinetic behavior is revealed. In that, the activated heme superoxo adduct is observed to undergo indole dioxygenation with the intermediacy of a non-covalently organized precursor complex, which forms prior to the rate-limiting step of the overall reaction landscape. Spectroscopic and theoretical characterization of this precursor complex draws close parallels to the ternary complex of heme dioxygenases, which has been postulated to be of crucial importance for successful 2,3-dioxygenative cleavage of indole moieties.