Smart fire alarm sensor (FAS) materials with mechanically robust, excellent flame retardancy as well as ultra-sensitive temperature-responsive capability are highly attractive platforms for fire safety application. However, most reported FAS materials can hardly provide sensitive, continuous and reliable alarm signal output due to their undesirable temperature-responsive, flame-resistant and mechanical performances. To overcome these hurdles, herein, we utilize the multi-amino molecule, named HCPA, that can serve as triple-roles including cross-linker, fire retardant and reducing agent for decorating graphene oxide (GO) sheets and obtaining the GO/HCPA hybrid networks. Benefiting from the formation of multi-interactions in hybrid network, the optimized GO/HCPA network exhibits significant increment in mechanical strength, e.g., tensile strength and toughness increase of ~ 2.3 and ~ 5.7 times, respectively, compared to the control one. More importantly, based on P and N doping and promoting thermal reduction effect on GO network, the excellent flame retardancy (withstanding ~ 1200 °C flame attack), ultra-fast fire alarm response time (~ 0.6 s) and ultra-long alarming period (> 600 s) are obtained, representing the best comprehensive performance of GO-based FAS counterparts. Furthermore, based on GO/HCPA network, the fireproof coating is constructed and applied in polymer foam and exhibited exceptional fire shielding performance. This work provides a new idea for designing and fabricating desirable FAS materials and fireproof coatings.

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A highly enantioselective Pd/Cu-catalyzed tandem C–C bond activation/Sonogashira reaction was developed with the aid of new TFSi-Phos, which provided chiral alkynyl indanones in good yields and enantioselectivities.

A palladium‐catalyzed enantioselective intramolecular σ‐bond cross‐exchange between C−I and C−C bonds is realized, providing chiral indanones bearing an alkyl iodide group and an all‐carbon quaternary stereocenter. Pd/TADDOL‐derived phosphoramidite is found to be an efficient catalytic system for both C−C bond cleavage and alkyl iodide reductive elimination. In addition to aryl iodides, aryl bromides can also be used for this transformation in the presence of KI. Density‐functional theory (DFT) calculation studies support the ring‐opening of cyclobutanones occuring through an oxidative addition/reductive elimination process involving PdIV species.

A graphene oxide (GO)-based smart fire alarm sensor (FAS) has gained rapidly increasing research interest in fire safety fields recently. However, it still remains a huge challenge to obtain desirable GO-based FAS materials with integrated performances of mechanical flexibility/robustness, harsh environment-tolerance, high-temperature resistance, and reliable fire warning and protection. In this work, based on bionic design, the supermolecule melamine diborate (M·2B) was combined with GO nanosheets to form supramolecular cross-linking nanosystems, and the corresponding GO-M·2B (GO/MB) hybrid papers with a nacre-like micro/nano structure were successfully fabricated via a gel-dry method. The optimized GO/MB paper exhibits enhanced mechanical properties, e.g., tensile strength and toughness up to ∼122 MPa and ∼1.72 MJ/m3, respectively, which is ∼3.5 and ∼6.6 times higher than those of the GO paper. Besides, it also shows excellent structural stability even under acid/alkaline solution immersion and water bath ultrasonication conditions. Furthermore, due to the presence of promoting reduction effect and atom doping reactions in GO network, the resulting GO/MB network displays exceptional high-temperature resistance, sensitive fire alarm response (∼0.72 s), and ultralong alarming time (>1200 s), showing promising fire safety and protection application prospects as desirable FAS and fire shielding material with excellent comprehensive performances. Therefore, this work provides inspiration for the design and fabrication of high-performance GO-based smart materials that combine fire shielding and alarm functions.

A palladium‐catalyzed enantioselective intramolecular σ‐bond cross‐exchange between C−I and C−C bonds is realized, providing chiral indanones bearing an alkyl iodide group and an all‐carbon quaternary stereocenter. Pd/TADDOL‐derived phosphoramidite is found to be an efficient catalytic system for both C−C bond cleavage and alkyl iodide reductive elimination. In addition to aryl iodides, aryl bromides can also be used for this transformation in the presence of KI. Density‐functional theory (DFT) calculation studies support the ring‐opening of cyclobutanones occuring through an oxidative addition/reductive elimination process involving PdIV species.

An atom‐economical strategy for the synthesis of functionalized alkylidenecyclobutanes (ACBs) via Lewis acid‐catalyzed yne‐carbonyl metathesis of ynamides and cyclobutanones is described. This strategy features mild reaction conditions, ready availability of starting materials, and broad functional group tolerability. Furthermore, the imide group is easily converted to acid, ester, and amide, thus providing an efficient access to various functionalized ACBs.

A facile synthesis of g,d-unsaturated ketones via palladium-catalyzed ring-opening of 2alkylidenecyclobutanols with organic halides is described. The key step involves C sp 3ÀC sp 2 bond cleavage via palladium-catalyzed b-carbon elimination. The desired g,d-unsaturated ketones are obtained in good to excellent yields and broad functional group tolerability. Aryl, heteroaryl, benzyl, and alkynyl halides all readily participate to forge tri-substituted carbon-carbon double bond in a stereoselective manner.