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Abstract Objective Researches about the association between serum albumin-to-globulin ratio (AGR) and the prognosis of lung cancer are limited. We aimed to investigate the relationship between AGR and overall survival (OS) in patients with advanced non-small-cell lung cancer (NSCLC) treated with anlotinib. Methods A retrospective cohort study was conducted on 196 advanced NSCLC patients with anlotinib treatment between June 1, 2018 and June 1, 2021. The exposure was AGR, calculated by baseline serum albumin / (serum total protein - serum albumin). The outcome was OS, defined as the period from the date of initial treatment with anlotinib to death or the last follow-up. The univariate and multivariate linear regression models and generalized additive models (GAM) were used to analyze the relationship between AGR and OS. The Kaplan-Meier method was used to analyze the OS. Results After adjusting for potential confounders, a non-linear relationship was observed between AGR and OS, which had an inflection point of 1.24. The hazard ratio and the confidence intervals on the left and the right sides of the inflection point were 13.05 (0.52 to 327.64) and 0.20 (0.07 to 0.57), respectively. It suggested that AGR was positively associated with OS when AGR was larger than 1.24, for every 1 unit increase in AGR, the risk of death lowered approximately by 80%. Conclusions The relationship between AGR and the OS for advanced NSCLC patients with anlotinib is non-linear. AGR level is an independent protective factor for OS in advanced NSCLC patients who received anlotinib therapy.

AbstractObjective To predict the risk of postoperative reintervention for uterine fibroids using clinical-imaging features and T2WI radiomics before high-intensity focused ultrasound (HIFU) ablation.Methods Among patients with uterine fibroids treated with HIFU from 2019 to 2021, 180 were selected per the inclusion and exclusion criteria (42 reintervention and 138 non-reintervention). All patients were randomly assigned to either the training (n = 125) or validation (n = 55) cohorts. Multivariate analysis was used to determine independent clinical-imaging features of reintervention risk. The Relief and LASSO algorithm were used to select optimal radiomics features. Random forest was used to construct the clinical-imaging model based on independent clinical-imaging features, the radiomics model based on optimal radiomics features, and the combined model incorporating the above features. An independent test cohort of 45 patients with uterine fibroids tested these models. The integrated discrimination index (IDI) was used to compare the discrimination performance of these models.Results Age (p

Hydroamidation of unactivated alkenes is an efficient way to introduce nitrogen-based functional groups to alkenes, however the regioselectivity requires directing groups. Here, the authors report the ligand-controlled NiH-catalyzed anti-Markovnikov intermolecular hydroamidation of unactivated alkenes with dioxazolones for the direct synthesis of N-alkyl amides.

Perovskite light‐emitting diodes (PeLEDs) based on 3D mixed Br‐Cl compositions have shown good color stability and efficiency in the sky‐blue color range. However, when the Cl/Br ratio increases to reach deep‐blue emission, the performance of the PeLEDs decreases drastically, with the external quantum efficiency (EQE) typically below 1%. Such performance decay is due largely to the poor morphology of the emissive layer. Herein, theoretical and experimental approach is combined to investigate the evolution of solvated lead complexes in the precursor solution of mixed Br–Cl perovskites. It is found that the energetically favorable exchange of halide ions in the lead complexes drives the precipitation of CsCl, leading to extremely low precursor solubility at high Cl/Br ratios and consequently poor perovskite film coverage. Based on the findings, a metastable dissolution strategy for perovskite film preparation is proposed and deep‐blue PeLEDs with a record high EQE of 4% in 3D‐based PeLEDs and excellent spectral stability is achieved.

Machine learning has revolutionized information processing for large datasets across various fields. However, its limited interpretability poses a significant challenge when applied to chemistry. In this study, we developed a set of simple molecular representations to capture the structural information of ligands in palladium-catalyzed Sonogashira coupling reactions of aryl bromides. Drawing inspiration from human understanding of catalytic cycles, we used a graph neural network to extract structural details of the phosphine ligand, a major contributor to the overall activation energy. We combined these simple molecular representations with an electronic descriptor of aryl bromide as inputs for a fully connected neural network unit. The results allowed us to predict rate constants and gain mechanistic insights into the rate-limiting oxidative addition process using a relatively small dataset. This study highlights the importance of incorporating domain knowledge in machine learning and presents an alternative approach to data analysis.

Furanocembranoid-like natural products with the alkene-substituted furan scaffold display a range of biological activities, but are difficult to access. Here, the authors report a modular biomimetic strategy to synthesise diverse alkene-substituted furan-containing macrolactams via palladium-catalysed unactivated Csp3-H olefination.

The gem-difluoroalkene functionality is relevant to drug design as it is a bioisostere of a carbonyl group. Here, the authors report the synthesis of 2,2-difluorovinyl benzoates as versatile building blocks for modular synthesis of gem-difluoroenol ethers and gem-difluoroalkenes by nickel-catalyzed cross coupling.

Coordination complexes based on polydentate ligands that contain both nitrogen and carbon ligating atoms are ubiquitous, but design of those with planar cores remains challenging. Here the authors show that complexes with planar CCCN, CCCCN and NCCCN cores can be accessed by modification of the coordinating atoms in CCCC core complexes.

Axially chiral allenes that are normally present in natural products, bioactive molecules, organocatalysts, and functional materials are usually produced from propargylic derivatives. Here, the authors show direct use of propargylic alcohols for catalytic asymmetric allene synthesis.

The Xian gamma-ray light source (XGLS) is a proposed novel high brightness gamma-ray source based on inverse Compton scattering (ICS) between the high brightness electron and laser beams. The photoinjector of the accelerator is one of the main components that determines the electron beam quality and related gamma-ray parameters [Phys. Rev. Accel. Beams 21, 030701 (2018)PRABCJ2469-988810.1103/PhysRevAccelBeams.21.030701; 20, 080701 (2017)PRABCJ2469-988810.1103/PhysRevAccelBeams.20.080701; 8, 100702 (2005)PRABFM1098-440210.1103/PhysRevSTAB.8.100702]. In order to reduce the risk of this project, a photoinjector including a laser-driven photocathode rf gun, two S-band tubes, and a diagnostic section was constructed and installed from 2016, serving as a pilot plant for the development of the key technologies for the projects. The injector is designed to deliver high quality electron bunches of typically 500 pC charge and ∼120 MeV energy with low emittance and jitter at 10 Hz repetition. Initial system commissioning with an electron beam was finished in the end of 2017, with a goal of a stable 0.6–0.7 mm mrad emittance in a 500-pC bunch clearly demonstrated. In this paper, we report the experimental results and experience obtained in the commissioning, including rf gun, drive laser system, timing and synchronization system, and beam diagnostics.

The mechanisms of the hydrosilylation reactions of unsaturated compounds with the tungsten complexes are examined by using the density functional theory method. The results have shown that the hydrosilylation of acetone has proceeded through a metal hydride migration, while the hydrosilylation of nitrile has occurred through a silyl migration mechanism.

The synthesis and structural, photophysical, electrochemical and electroluminescent properties of a novel class of trifunctional Pt(II) cyclometalated complexes are described in which the hole-transporting triarylamine, electron-transporting oxadiazole and electroluminescent metal components are integrated into a single molecule. The management of the relative electroluminescent (EL) intensities of the singlet and triplet excitons is shown to be a good tool for making efficient single-dopant white organic light-emitting devices (WOLEDs).

The mechanism of allylative dearomatization catalyzed by palladium is investigated using density functional calculations at the B3LYP level. Results reveal that the intermediate -([eta.sup.3]-benzyl)([eta.sup.1]-allyl-Pd(PH3) is responsible for the formation of the kinetically favored dearomatic product.

A strong trans influence of boryl ligands together with other ligands are investigated by density functional theory (DFT) calculations on a series of square-planar platinum(II) complexes. It is observed that sigma-donor strength and pi-acceptors are the major factors, which enhance the Trans- influence properties of the boryl legands.

The synthesis of zirconium, hafnium, and tantalum amide silyl complexes are described. The novel reactions of silyl ligands, gamma-hydrogen abstraction to give metallaheterocyclic moiety were investigated.

Research has been conducted on the transition-metal chalcogenide clusters. The electronic structures of these electron-rich octahedrally condensed clusters have been investigated via the use of Huckel and density functional molecular orbital calculations and the results are reported.

A theoretical study of the TpIrH (sub 4) system is discussed. A comparison of the experimental infrared spectrum of TpIrH4 and harmonic frequency calculations support the assignment of C (sub s) and C (sub i) structures.

The stability of three structural isomers, Th, D3d and Td, of M8C12, where M = Mo, Nb, Y and Zr, are analyzed using ab initio analaysis. The great stability of Td form, the bonds of the complex and the 'magic number' are derived. The Td form is a butterfly-shaped, tetracapped tetrahedral with six C2 units.

Spectroscopic and crystallographic analysis of the reaction of benzeneseleninic anhydride and hexamethyldisilazane, which yields the reactive intermediate of oligomeric (RSeN)4 that oxidizes a phenol to the selenoiminoquinone 1, revealed that the oxygen atom of the carbonyl group in the (phenylselenoimino)quinone 2 participates in an interaction with the selenium atom. There are unexpected interactions between an oxygen atom and chalcogen that affects the structure of the molecules.

Ab initio quantum chemical calculations are applied in the study of associative mechanisms in the substitution reactions of 17- and 18-electron metal hexacarbonyls. It was found that the transition-metal complexes had a pseudo-C2v transition state. The substitution reaction of a 17-electron transition-metal complex has a three-center five-electron bond in the transition state. The most notable difference between the substitution reaction rates of the 17- and 18-electron complexes is the large difference in the valence-electron charge distributions of the corresponding transition states.

DFT calculations have been performed to study the relative preference of different unsaturated organic molecules (CO2, PhCHO and styrene) for insertion into different Cu--X (X = B, C, O) bonds, which are competing processes in copper-catalyzed three-component boracarboxylation reactions involving CO2 and B2pin2. In this work, the variations in the insertion barriers and in the relative stability of the insertion products have been systematically analyzed and discussed in-depth. Our DFT calculations also allow us to make a prediction that when both aldehyde and styrene are present with CO2 and B2pin2, styrene will undergo the three-component boracarboxylation reaction rather than the aldehyde. [ABSTRACT FROM AUTHOR]

Clusters of group 14 elements show plenty of similarities with borane clusters. As such, chemists often try to understand their structure and bonding on the basis of Wade’s rules to predict and classify various clusters. Such practice, albeit very common, often faces challenges and difficulties due to significant differences in the bonding abilities between group 13 and 14 atoms, as well as the changes in the ionization energies and radial characteristics of atomic orbitals as the groups are descended. In this chapter, we have extensively discussed the structure and bonding of a wide variety of group 14 clusters, including bare clusters, substituent-decorated clusters, endohedral clusters, transition metal doped clusters, and their combinations. By thoroughly analyzing their electronic structures within the framework of molecular orbital theory, we have summarized their bonding patterns and explored the factors that affect the applicability of Wade’s rules in various group 14 clusters. [ABSTRACT FROM AUTHOR]

Modular bonding picture is a central part of chemical understanding as exemplified by the wide usage of Lewis structure as a chemical language to describe molecular electronic structures. A chemically intuitive bonding picture requires the descriptors to be localized and transferable. Molecular orbitals directly derived from quantum calculations are too delocalized to interpret in this regard, hence many efforts have been devoted to the development of bonding analysis methods. After a brief overview of various bonding analysis methods, this review outlines the framework of principal interacting orbital (PIO) analysis and presents its role in recovering intuitive chemical concepts and producing modular bonding pictures. The PIO analysis identifies the most important fragment orbitals that are involved in fragment interactions and characterizes a one-to-one orbital interaction pattern that underlies a unique set of bonding and anti-bonding orbitals derived from pairwise orbital interactions between two fragments. By making use of the principal component analysis (PCA), PIO analysis can effectively combine complex delocalized interaction patterns involved in numerous molecular orbitals into a handful of localized PIOs to provide easily interpretable results with intimate connection to localized chemical concepts, while maintaining necessary delocalized features when dealing with systems that involve mutlicentered interactions such as cluster compounds and various reactions. Such adaptability guarantees the robustness of PIO analysis with respect to change of substituents and the transferability of obtained PIOs across different systems. [ABSTRACT FROM AUTHOR]

The catalytic activity of a series of ruthenium(II) complexes in azide-alkyne cycloaddition is examined. Density functional theory calculations have shown that the reductive elimination step is rate-determining and the ruthenium-catalyzed azide-alkyne cycloaddition has proceeded via oxidative coupling of the azide and alkyne reactants to give a six-membered ruthenacycle intermediate.

The detailed mechanism for the diboration of aldehydes catalyzed by (NHC)Cu(boryl) complexes (NHC = N-heterocyclic carbene) is analyzed with the help of density functional theory by calculating the relevant intermediated and transition states. The insertion intermediate has isomerized easily to a 1,2-dihydropyridine form, preventing its metathesis with a diboron reagent to give the expected diboration product as observed for other aldehyde substrates.

The article explains the formation of various aminoxy and unusual (aminomethyl)amide oxo complexes by the reacting Ta[(N[Me.sub.2]).sub.5] with [O.sub.2]. The peroxide ligand is found to play a very important role in the reaction.

DFT calculations were used to study the detailed mechanism for the reduction of CO2 to CO catalyzed by (NHC)Cu(boryl) complexes. It is seen that the electron richness of the Cu-boryl bond, due the low electronegativity of boron, gives rise to a small CO2 insertion barrier because the back-bonding interaction between the Cu-B (sigma)-bond and the CO2 carbon is important in the insertion process.

Density functional theory (DFT) calculations are performed to examine the reaction mechanism of hydrosilylation of carbonyl compounds catalyzed by high-valent rhenium(V)-di-oxo complexes ReO2I-(PR3)2 (R = Me, Ph). The results have indicated that the most favorable mechanisms involved the rate-determining dissociative [2+2] addition of the Si-H bond across a Re=O bond to form a Re(V) hydrido siloxy intermediate and the additional oxo ligand in the ReO2I(PR3)2 complexes has promoted the [2+2] addition across the rhenium-oxo bond both kinetically and thermodynamically.

New Ag(I) supramolecular complexes were synthesized by the reactions of Ag(I) salts with two well-designed rigid bulky acridine-based ligands using elemental analyses, IR spectroscopy, and single-crystal X-ray diffraction analysis, respectively. The new suprameolcular complexes exhibit rare C-H...Ag H-bonding and Ag-O weak interactions.

The kinetics and mechanistic study of the BF3-activated oxidation of alkanes and arylalkanes by KMnO4 are reported. The results have demonstrated that BF3 forms an adduct with MnO(sub 4)(super -) in CH3CN that oxidizes hydrocarbons at rates over 7 orders of magnitude faster than that by MnO(sub 4)(super -) alone.

Palladium-catalyzed terminal alkyne dimerization through oxidative homocoupling is a useful approach to the synthesis of symmetrical 1,4-diynes. Recent investigation suggested that this reaction might be accomplished in the absence of intentionally added stoichiometric oxidants to reoxidise Pd(0) to Pd(II).

Thermodynamic, kinetic and theoretical studies of the exchange between alkylidyne alkyl and bis(alkylidene) tungsten complexes are reported. This exchange involves phosphine coordination, which stabilizes the bis(alkylidene) tautomer so that it is observable at room temperature.

The synthesis and characterization of undecanuclear copper clusters and bromide centered Cu(super 1)(sub 8) cubic clusters are explained and the Cu-mu(sub 9)-Se interaction in this clusters are studied by using molecualr orbital calculations. It is found that the geometry for the nono coordinate selenium atom is tricaped trigonal prismatic and the formal bond order of Cu-mu(sub 9)-Se bond is highly smaller than half of that calculated for terminal Cu-mu(sub 2)-Se bonds.

The promotion of a catalytic reaction by the use of a M-H...H-X dihydrogen-bonding interaction in an indenylruthenium hydride system is discussed. The reaction barrier of (eta5-C9H7)Ru(dppm)H is lowered by the presence of a Ru-H...H-OH dihydrogen-bonding interaction in the transition state.

The fullerene-porphyrin interaction energies obtained for the four complexes are in the range from -16 to -18 kcal/mol. The change in the interaction energies ongoing from fullerene-porphyrin to fullerene-metalloporphyrin has not been significant because the increase of the electrostatic attractive forces has been offset by the increase of Pauli repulsive interactions.

An experiment is conducted for the first time wherein the metallabenzynes can go through electrophilic substitution reactions and this permits us to form novel forms of metallabenzynes. In fact, in the protonation and bromination processes just the C3 and C5 carbon atoms of the metallacyle are harassed by electrophiles.