Geometrically Compelled Silicon(II)/Silicon(IV) Donor-Acceptor Interaction Enables the Enamination of Nitriles.

Discovering new bonding scenarios and subsequently exploring the reactivity contribute substantially to advance the main group element chemistry. Herein, we report on the isolation and characterization of an intriguing class of the hydrido-benzosiloles 2-4. These compounds exhibit a side arm of the amidinatosilylenyl group, featuring unidirectional silicon(II)/silicon(IV) donor-acceptor interaction on account of the geometric constraint. Furthermore, the reactions involving 2-4 with nitriles yield the tricyclic compounds that edge-fused of the Si-heteroimidazolidine-CN2 Si2 , silole-C4 Si, and phenyl-C6 -rings (5-13). These compounds are manifesting a unique reaction that the silicon(II)/silicon(IV) interaction enables the enamination of the α-H-bearing nitriles. The reaction mechanism involved in H-shift under oxidative addition at silylene followed by hydrosilylation of a ketenimine intermediate was revealed by density function theory (DFT) calculations.

Albumin/fibrinogen ratio, an independent risk factor for postoperative delirium after total joint arthroplasty.

AIM: Postoperative delirium (POD) is a very common and serious complication after total joint arthroplasty (TJA), which is closely associated with many adverse consequences and a poor prognosis. This study aimed to establish the potential risk factors for POD. METHODS: In total, 336 patients who underwent elective TJA under general anesthesia between 2018 and 2021 were included and deemed eligible for inclusion. POD was diagnosed based on the criteria by the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM V). The receiver operating characteristic curve was drawn to evaluate the predictive and cut-off values of continuous variables for POD. Potential risk factors for POD were evaluated by binary univariate and multivariate analysis with the "Enter" method. RESULTS: According to the criteria by DSM V, 43 patients were categorized into the POD group, with an incidence of 12.8% (43 of 336). The receiver operating characteristic curve showed that albumin/fibrinogen ratio (AFR) was a good predictor for POD with an area under the curve of 0.754, cut-off value of 9.65, sensitivity of 57.00% and specificity of 83.72% (P <0.001). A low preoperative AFR level (<9.65) was determined as the only independent risk factor for POD by the univariate and multivariate logistic regression analyses (OR: 2.45, 95% CI: 2.01-2.94, P = 0.008). CONCLUSIONS: Our results indicate that a low AFR is an independent risk factor for POD in elderly subjects after TJA. Geriatr Gerontol Int 2022; 22: 412-417.

Platinum69-cobalt31 alloyed nanosheet nanoassemblies as advanced bifunctional electrocatalysts for boosting ethylene glycol oxidation and oxygen reduction.

Pt-based bimetallic nanocrystals are feasible to dramatically improve the catalytic performances in fuel cells via morphology- and composition-engineering. Herein, bimetallic platinum69-cobalt31 nanosheet nanoassemblies (Pt69Co31 NSNSs) were facilely synthesized through a one-pot co-reduction solvothermal strategy in oleylamine (OAm), using cetyltrimethylammonium chloride (CTAC) and allantoin as the directing agents. The current synthesis highly depended on the critical concentrations of Pt and Co precursors, the combined use of allantoin to OAm as the co-reductant, and the use of proper allantoin concentration. The obtained nanocatalyst exhibited largely enhanced electrocatalytic activity and durable ability towards ethylene glycol oxidation reaction (EGOR) and oxygen reduction reaction (ORR) relative to home-made Pt85Co15 nanoparticles (NPs), Pt19Co81 NPs and Pt black catalysts due to its much larger electrochemically active surface area than the contrasts.

A novel label-free electrochemical immunosensor based on the enhanced catalytic currents of oxygen reduction by AuAg hollow nanocrystals for detecting carbohydrate antigen 199.

Herein, bimetallic alloyed AuAg hollow nanocrystals (AuAg HNCs) were prepared by a simple one-pot aqueous method using polycytidysic acid (PCA) as the green growth-directing agent. The novel immunosensor for carbohydrate antigen 199 (CA199) was further constructed based on the enhanced catalytic currents of oxygen reduction reaction (ORR) by AuAg HNCs. By virtue of the good biocompatibility and catalytic activity of AuAg HNCs, the immunosensor exhibited superior analytical performance for the assay of CA199 under the optimal experimental conditions, the ORR signals linearly decreased with the increased CA199 concentrations in the range of 1 ~ 30UmL-1, with the low detection limit of 0.228UmL-1, improved stability, reproducibility and selectivity.

l-Arginine-assisted one-pot synthesis of hierarchical Ag1Pt2 nanocorallines for surface-enhanced Raman spectroscopy.

The hierarchical multi-branched Ag1Pt2 nanocorallines (NCs) were prepared in a large scale by a rapid aqueous method, using l-arginine as the eco-friendly shape-directing agent. The product was mainly characterized by microscopy measurements, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The architectures exhibited superior surface-enhanced Raman scattering (SERS) with 4-nitrothiophenol (4-NTP), the enhancement factor (EF) of 1.3×105, a wide linear range of 10-100µM and a low detection limit of 0.01µM. Meanwhile, the SERS-active substrate was explored for the assay of 4-mercaptobenzoic acid (4-MBA) with significantly enhanced SERS performance. It means Ag1Pt2 NCs as a good Raman-active platform for sensing in food and environment analysis, owing to their rough surfaces and unique multi-branched structures.