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Novel graphene-like nanomaterials with a non-zero bandgap are important for the design of gas sensors. The selectivity toward specific targets can be tuned by introducing appropriate functional groups on their surfaces. In this study, we use first-principles simulations, in the form of density functional theory (DFT), to investigate the covalent functionalization of a single-layer graphitized BC6N with azides to yield aziridine-functionalized adducts and explore their possible use to realize ammonia sensors. First, we determine the most favorable sites for physical adsorption and chemical reaction of methylnitrene, arising from the decomposition of methylazide, onto a BC6N monolayer. Then, we examine the thermodynamics of the [1 + 2]–cycloaddition reaction of various phenylnitrenes and perfluorinated phenylnitrenes para-substituted with (R = CO2H, SO3H) groups, demonstrating favorable energetics. We also monitor the effect of the functionalization on the electronic properties of the nanosheets via density of states and band structure analyses. Finally, we test four dBC6N to gBC6N substrates in the sensing of ammonia. We show that, thanks to their hydrogen bonding capabilities, the functionalized BC6N can selectively detect ammonia, with interaction energies varying from −0.54 eV to −1.37 eV, even in presence of competing gas such as CO2 and H2O, as also confirmed by analyzing the change in the electronic properties and the values of recovery times near ambient temperature. Importantly, we model the conductance of a selected substrate alone and in presence of NH3 to determine its effect on the integrated current, showing that humidity and coverage conditions should be properly tuned to use HO2C-functionalized BC6N-based nanomaterials to develop selective gas sensors for ammonia. [ABSTRACT FROM AUTHOR]

Iron‐catalyzed C−H amination is emerging as an attractive and sustainable method to install amine functionalities into organic compounds. Amination of C(sp3)−H bonds is usually mediated by an iron‐nitrene intermediate via a Hydrogen Atom Abstraction/Radical Recombination mechanism reminiscent of biomimetic C−H oxidation. Accordingly, this transformation can be catalyzed by engineered iron enzymes, heme and nonheme iron complexes as well as iron salts, although it is often limited to intramolecular reactions and/or activated positions. Aromatic C(sp2)−H amination is mediated by addition of electrophilic iron nitrenes or protonated N‐radical intermediates (produced with Fe catalysts) to aromatic systems. Again, high selectivity is obtained via (pseudo) intramolecular reactions. From a mechanistic perspective, several iron nitrene intermediates have been isolated and characterized over the years in different ligand scaffolds and iron oxidation states. Structure‐activity correlations have been drawn only in few cases and point to a key role of the spin density on the nitrene ligand and of the iron oxidation state. This review describes the state of the art for homogeneous iron catalyzed C(sp3)−H and C(sp2)−H amination focusing on the last 5 years (2019–2023) from a mechanism‐driven catalyst design perspective. [ABSTRACT FROM AUTHOR]

N‐phenyl dibenzothiophene sulfoximine has been demonstrated to produce phenyl nitrene and dibenzothiophene S‐oxide upon irradiation with UV‐A light, and dibenzothiophene S‐oxide upon further irradiation releases triplet atomic oxygen. Thus, N‐phenyl dibenzothiophene sulfoximine exhibits a rare dual‐release capability in its photochemistry. In this work, N‐substituted dibenzothiophene sulfoximine derivatives are irradiated with UV‐A light to compare their photochemistry and quantum yield of dibenzothiophene S‐oxide production with that of N‐phenyl dibenzothiophene sulfoximine. Both N‐aryl and N‐alkyl derivatives of dibenzothiophene sulfoximine are examined to observe their effects on the quantum yield of the photolysis reaction. Adding electron withdrawing N‐aryl substituents is shown to increase the quantum yield of dibenzothiophene S‐oxide production, while adding electron donating N‐aryl substituents is shown to decrease the quantum yield. The quantum yield was slightly lowered or not increased by most N‐alkyl substituents. Furthermore, the quantum yield was not augmented by branching and steric hindrance effects associated with the N‐alkyl substituents. These results suggest that electronic modulation of the sulfoximine bonds affects the observed photolysis reaction. [ABSTRACT FROM AUTHOR]

This document provides technical information about the synthesis and characterization of a pink solid compound. The compound is synthesized using a literature procedure and has a melting point of 189-190 °C. The document includes data from various analytical techniques, such as IR, NMR, and HRMS, which provide information about the compound's structure and composition. The authors acknowledge the assistance of several individuals and provide a link to additional supporting information. [Extracted from the article]

Pyridines are valuable pharmacophores, and their access via direct and selective transmutation of carbon atom with desired nitrogen could become crucial in drug discovery processes. However, only scarce examples can be found when it comes C‐to‐N‐transmutation reactions of aromatics that could lead to the facile synthesis of pyridines or other azaarenes. In this context, Levin and co‐workers recently disclosed a process leading to pyridines from the corresponding aryl azides via the regioselective nitrene internalization process. Notably, the transformation did not lead to any further modification of the rest of the aromatic skeleton. This innovative work enabled selectively accessing various pyridine derivatives through direct nitrogen scan operations on benzene derivatives, which were otherwise not feasible. [ABSTRACT FROM AUTHOR]

N‐Trifluoromethylated organics may be applied in drug design, agrochemical synthesis, and materials science, among other areas. Yet, despite recent advances in the synthesis of aliphatic, cyclic and heterocyclic N‐trifluoromethyl compounds, no strategy based on trifluoromethyl nitrene has hitherto been explored. Here we describe the formation of triplet trifluoromethyl nitrene from azidotrifluoromethane, a stable and safe‐to‐use precursor, by visible light photocatalysis. The addition of CF3N to alkenes via biradical intermediates afforded previously unknown aziridines substituted with trifluoromethyl group on the nitrogen atom. The obtained aziridines were converted into either N‐trifluoromethylimidazolines, via formal [3+2] cycloaddition with nitriles, mediated by a Lewis acid, or into N‐trifluoromethylaldimines, via ring opening and aryl group migration mediated by a strong Brønsted acid. Our findings open new opportunities for the development of novel classes of N‐CF3 compounds with possible applications in the life sciences. [ABSTRACT FROM AUTHOR]

Herein, we report an operationally simple and efficient protocol to prepare sulfonyl carbamimidic azide and N‐sulfonyl aminotetrazole via Co‐catalyzed three component coupling of sulfonyl azide (acts as nitrene source), isocyanide, and TMS‐azide at room temperature under visible light. Initially, the carbamimidic azide is formed, which cyclizes only in the presence of base to deliver N‐sulfonyl aminotetrazole in very good yields. The sulfonyl aminotetrazole can also be synthesized directly without isolating the carbamimidic azide in the presence of base. The sulfonyl azide is anticipated to generate nitrene and reacts with isocyanide to produce carbodiimide. Subsequent addition of azide (TMS‐N3) to carbodiimide results in the formation of carbamimidic azide. [ABSTRACT FROM AUTHOR]

A modular platform for facile access to 1,2,3,9‐tetrahydro‐4H‐carbazol‐4‐ones (H4‐carbazolones) and 3,4‐dihydrocyclopenta[b]indol‐1(2H)‐ones (H2‐indolones) is described. The requisite 6‐ and 5‐membered 2‐arylcycloalkane‐1,3‐dione precursors were readily obtained through a Cu‐catalyzed arylation of 1,3‐cyclohexanediones or by a ring expansion of aryl succinoin derivatives. Enolization of one carbonyl group in the diones, conversion to a leaving group, and subsequent azidation gave 2‐aryl‐3‐azidocycloalk‐2‐en‐1‐ones. This two‐step, one‐pot azidation is highly regioselective with unsymmetrically substituted 2‐arylcyclohexane‐1,3‐diones. The regioselectivity, which is important for access to single isomers of 3,3‐disubstituted carbazolones, was analyzed mechanistically and computationally. Finally, a Rh‐catalyzed nitrene/nitrenoid insertion into the ortho C−H bond of the aryl moiety gave the H4‐carbazolones and H2‐indolones. One carbazolone was elaborated to an intermediate reported in the total synthesis of N‐decarbomethoxychanofruticosinate, (−)‐aspidospermidine, (+)‐kopsihainanine A. With 2‐phenylcycloheptane‐1,3‐dione, prepared from cyclohexanone and benzaldehyde, the azidation reaction was readily accomplished. However, the Rh‐catalyzed reaction unexpectedly led to a labile but characterizable azirine rather than the indole derivative. Computations were performed to understand the differences in reactivities of the 5‐ and 6‐membered 2‐aryl‐3‐azidocycloalk‐2‐en‐1‐ones in comparison to the 7‐membered analogue, and to support the structural assignment of the azirine. [ABSTRACT FROM AUTHOR]

Here we report the use of a base metal complex [(tBupyrpyrr2)Fe(OEt2)] (1‐OEt2) (tBupyrpyrr22−=3,5‐tBu2‐bis(pyrrolyl)pyridine) as a catalyst for intermolecular amination of Csp3−H bonds of 9,10‐dihydroanthracene (2 a) using 2,4,6‐trimethyl phenyl azide (3 a) as the nitrene source. The reaction is complete within one hour at 80 °C using as low as 2 mol % 1‐OEt2 with control in selectivity for single C−H amination versus double C−H amination. Catalytic C−H amination reactions can be extended to other substrates such as cyclohexadiene and xanthene derivatives and can tolerate a variety of aryl azides having methyl groups in both ortho positions. Under stoichiometric conditions the imido radical species [(tBupyrpyrr2)Fe{=N(2,6‐Me2‐4‐tBu‐C6H2)] (1‐imido) can be isolated in 56 % yield, and spectroscopic, magnetometric, and computational studies confirmed it to be an S = 1 FeIV complex. Complex 1‐imido reacts with 2 a to produce the ferrous aniline adduct [(tBupyrpyrr2)Fe{NH(2,6‐Me2‐4‐tBu‐C6H2)(C14H11)}] (1‐aniline) in 45 % yield. Lastly, it was found that complexes 1‐imido and 1‐aniline are both competent intermediates in catalytic intermolecular C−H amination. [ABSTRACT FROM AUTHOR]

The exponential proliferation of conformers makes it impossible to examine the entire population in most systems. Controlling conformational ensembles is thus pivotal in many areas of chemistry. Rh2(esp)2, a dicarboxylate‐derived paddlewheel rhodium complex, is one of the most effective catalysts for nitrene chemistry. Its enormous success has led to preparing many analogous complexes. However, there has been little consideration for the conformational dynamics of the parent catalyst. Herein, we report a new ligand modification principle that prevents conformer interconversion. The resulting complex comprises two isolable conformers, whose structures have been determined by X‐ray diffraction. Combined experimental and computational data has revealed similarities and dissimilarities between the conformationally confined and parent complexes. Three model cases have demonstrated the utility of conformational fixation in the development of stereoselective catalysts for nitrene transfer reactions. The design principle described in this study can be combined with other established modification strategies, serving as a springboard for further advancement of the chemistry of paddlewheel metal complexes. [ABSTRACT FROM AUTHOR]

Treatment of 1‐azido‐2‐(2,2‐dihalovinyl)arenes with a catalytic amount of Rh2(esp)2 afforded various 2,3‐dihaloindoles in 51–74% yields. This reaction progressed via the intramolecular cyclization of rhodium nitrene generated in situ and the rearrangement of one halogen group. For the 2‐chloro‐2‐iodovinyl group, the iodo group selectively rearranged to yield 2‐chloro‐3‐iodoindoles as single isomers. Moreover, 1‐azido‐2‐[(2,2‐dihalomovinyl)(Boc)amino]arenes were reacted with a catalytic amount of Rh2(oct)4, which produced 2‐haloquinoxaline in 55–92% yields. [ABSTRACT FROM AUTHOR]

We report an unusual transformation where the transient formation of a nitrene moiety initiates a sequence of steps leading to remote oxidative C–H functionalization (R–CH3 to R–CH2OC(O)R') and the concomitant reduction of the nitrene into an amino group. No external oxidants or reductants are needed for this formal molecular comproportionation. Detected and isolated intermediates and computational analysis suggest that the process occurs with pyrazole ring opening and recyclization. [ABSTRACT FROM AUTHOR]

Übergangsmetallnitride/nitrene sind vielversprechende Reagenzien für katalytischen Stickstoffatomtransfer, die in situ durch optisch induzierte N2‐Eliminierung aus Azidkomplexen zugänglich sind. Um ihr synthetisches Potenzial für die Katalyse voll ausschöpfen zu können, ist ein grundlegendes Verständnis der primären photoinduzierten Prozesse und der stereoelektronischen Faktoren, welche die N2‐Dissoziation kontrollieren, unerlässlich. Mit Hilfe von Femtosekunden‐Infrarotspektroskopie klären wir hier die primären molekularen Mechanismen auf, die für die Bildung eines einzigartigen Platin(II)nitrens mit Triplett‐Grundzustand aus einem geschlossenschaligen Platin(II)azidkomplex verantwortlich sind. Die spektroskopischen Daten in Kombination mit quantenchemischen Rechnungen ergeben einen konsistenten Mechanismus: Produktbildung erfordert die anfängliche Besetzung eines angeregten Singulett‐Zustands mit anionischen Azid‐Diradikal‐Liganden, der an ein low‐spin d8‐konfiguriertes PtII‐Ion gebunden ist. Anschließende Interkombination erzeugt das an Platin gebundene Triplett‐Aziddiradikal, welches sich durch N2‐Verlust in einer nahezu barrierelosen, adiabatischen Dissoziation nahtlos in das Triplett‐Nitren umwandelt. Unsere Daten unterstreichen die Bedeutung des produktiven, N2‐freisetzenden Zustands mit Azid ππ* Charakter als Konstruktionsprinzip für den Zugang zu effizienten Stickstoffatomtransfer‐Katalysatoren. [ABSTRACT FROM AUTHOR]

The dinitrene 2,3,5,6‐tetrafluoro‐1,4‐phenylenedinitrene was synthesized by photolysis of matrix‐isolated 1,4‐diazido‐2,3,5,6‐tetrafluorobenzene at 365 or 405 nm in high yields at cryogenic temperatures and characterized by FT‐IR, UV‐Vis, and EPR spectroscopy. The electronic structure of the dinitrene is described best as a quinoidal diradical with an open‐shell singlet ground state and a triplet state laying only 650 ± 5 cal/mol higher in energy. Irradiation with λ = 254 nm results in fragmentation of the dinitrene into FCCF and several olefins which on prolonged photolysis fragment into FCCCN, FCCNC, and FCN. [ABSTRACT FROM AUTHOR]

In this study, the reactivity of the alkyl nitrenes, generated from the substituted hydroxylamine precursors, was determined using the same rhodium catalyst. The results revealed that in competitive C–H insertion experiments, the regioselectivity between benzylic and tertiary C–H bonds could be modulated by adding Brønsted acids or changing the substituents on oxygen. This study enhances our understanding of the metallonitrene structures and provides valuable insights for further development of selective N-heterocycle syntheses.

The development of an efficient catalytic system enabling the conversion of alkanes to valuable nitrogen‐containing building blocks is reported. Light alkanes can be selectively functionalized by an intermolecular C(sp3)−H amination reaction that proceeds at room temperature in the presence of only 1 mol % of a dirhodium(II) complex. Selective amination of tertiary C(sp3)−H within acyclic or cyclic alkanes used as limiting components leads to the corresponding amides isolated with yields in the 51–96 % range. The reaction, that can be performed on a gram‐scale, applies with equal levels of efficiency and selectivity to more complex hydrocarbons. [ABSTRACT FROM AUTHOR]

Sulfondiimines are marginalized entities among nitrogen‐containing organosulfur compounds, despite offering promising properties for applications in various fields including medicinal and agrochemical. Herein, we present a metal‐free and rapid synthetic procedure for the synthesis of N‐monosubstituted sulfondiimines that overcomes current limitations in their synthetic accessibility. Particularly, S,S‐dialkyl substrates, which are commonly difficult to convert by existing methods, react well with a combination of iodine, 1,8‐diazabicyclo[5.4.0]undec‐7‐en (DBU), and iminoiodinanes (PhINR) in acetonitrile (MeCN) to furnish the corresponding sulfondiimines in yields up to 85 % (25 examples). Valuable "free" NH‐N′H‐sulfondiimines can then be accessed by N‐deprotection under mild reaction conditions. Several experimental observations suggest a mechanistic pathway diverging from the common radical‐based iodine/iminoiodinane mechanism. Based on the experimental results in combination with data obtained by 1H NMR spectroscopy, ESI mass spectrometry, and crystallographic analysis we propose a direct amination from PhINNs and a reaction path via a cationic iodonitrene. [ABSTRACT FROM AUTHOR]

To impart high stretchability to semiconducting polymers, researchers have used a photocrosslinking approach based on the nitrene chemistry of an azide‐incorporated molecular additive. However, understanding of the molecular design of azide crosslinkers with respect to their effects on the electrical and mechanical properties of semiconducting polymer thin films is lacking. In this study, the effects of an azide photocrosslinker's molecular length and structure on the microstructural, electrical features, and stretchability of photocrosslinked conjugated polymer films is investigated. For a systematic comparison, a series of nitrene‐induced photocrosslinkers (n‐NIPSs) with different numbers of ethylene glycol repeating units (n = 1, 4, 8, 13) that bridge two tetrafluoro‐aryl azide end groups is synthesized. Two semicrystalline conjugated polymers and two nearly amorphous conjugated polymers are co‐processed with n‐NIPSs and crosslinked by brief exposure to UV light. It is found that, among the synthesized n‐NIPSs, the shortest one (1‐NIPS) is the most efficient in improving the stretchability of crosslinked indacenodithiophene‐benzothiadiazole films and that the improvement is achieved only with nearly amorphous polymers, not with semicrystalline conjugated polymers. On the basis of systematic studies, it is suggested that crosslinking density in amorphous regions is important in improving thin film stretchability. [ABSTRACT FROM AUTHOR]

Since gold is located well beyond the oxo wall, chemical species with terminal Au−N and Au−O units are extremely rare and limited to low coordination numbers. We report here that these unusual units can be trapped within a suitable organometallic frame. Thus, the terminal auronitrene and auroxyl derivatives [(CF3)3AuN]− and [(CF3)3AuO]− were identified as local minima by calculation. These open‐shell, high‐energy ions were experimentally detected by tandem mass spectrometry (MS2): They respectively arise by N2 or NO2 dissociation from the corresponding precursor species [(CF3)3Au(N3)]− and [(CF3)3Au(ONO2)]− in the gas phase. Together with the known fluoride derivative [(CF3)3AuF]−, they form an interesting series of isoleptic and alloelectronic complexes of the highly acidic organogold(iii) moiety (CF3)3Au with singly charged anions X− of the most electronegative elements (X=F, O, N). Ligand‐field inversion in all these [(CF3)3AuX]− species results in the localization of unpaired electrons at the N and O atoms. [ABSTRACT FROM AUTHOR]

Crosslinking polymers to form networks is a universal and routinely applied strategy to improve their stability and endow them with solvent resistance, adhesion properties, etc. However, the chemical crosslinking of common commercial polymers, especially for those without functional groups, cannot be achieved readily. In this study, we utilized low-molecular weight poly(glycidyl azide) (GAP) as polymeric crosslinkers to crosslink various commercial polymers via simple ultraviolet light irradiation. The azide groups were shown to decompose upon photo-irradiation and be converted to highly reactive nitrene species, which are able to insert into carbon-hydrogen bonds and thus crosslink the polymeric matrices. This strategy was demonstrated successfully in several commercial polymers. In particular, it was found that the crosslinking is highly localized, which could endow the polymeric matrices with a decent degree of crosslinking without significantly influencing other properties, suggesting a novel and robust method to crosslink polymeric materials. [ABSTRACT FROM AUTHOR]

An account of our development of reactions to construct N -heterocycles by triggering cyclization–migration tandem reactions from aryl azides, nitroarenes, and aryl amines is described. The reactivity patterns of metal N -aryl nitrenes, nitrosoarenes, N -aryl nitrogen radical anions, and N -aryl nitrenoids are compared. 1 Introduction 2 Unlocking the Reactivity Embedded in Aryl Azides 3 Exploiting the Reactivity of Nitrosoarenes Generated from Nitroarenes 4 Radical Anion N -Aryl Nitrogen Reactive Intermediates from Nitroarenes 5 Oxidation of Aryl Amines to Access Electrophilic N -Aryl Nitrenoids 6 Conclusion [ABSTRACT FROM AUTHOR]

Nitrenoid-mediated C–H insertion and cycloaddition reactions are gaining increasing importance in modern organic synthesis. However, the nitrene-mediated benzene ring expansion, which constitutes a potent tool for breaking the benzene ring, has sparely been explored for synthetic purposes. Herein we report that nitrene cycloaddition to the benzene ring can be enabled intramolecularly by iron catalysis. By using FeCl2 and N -heterocyclic carbene SIPr·HCl as the catalyst, α-azido- N -phenylamides can be converted into 1,3-dihydro-2 H -azepin-2-ones in good yields through a novel skeleton rearrangement. The rearrangement features a cascade of nitrene cycloaddition, C–N cleavage, water addition, and electrocyclic ring-opening. In the case that the N -phenyl ring is substituted with a methoxy group at the meta or para position, azepin-2-one-fused imidazolinones can also be obtained. The present reactions provide an effective method for benzene ring expansion as well as for the preparation of azepin-2-one compounds. [ABSTRACT FROM AUTHOR]

We report an unusual transformation where the transient formation of a nitrene moiety initiates a sequence of steps leading to remote oxidative C–H functionalization (R–CH3 to R–CH2OC(O)R’) and the concomitant reduction of the nitrene into an amino group. No external oxidants or reductants are needed for this formal molecular comproportionation. Detected and isolated intermediates and computational analysis suggest that the process occurs with pyrazole ring opening and recyclization.

The synthesis of non‐racemic 5‐membered cyclic carbonates from abundant alcohols is reported. Conversion of the alcohol into an azanyl carbonate is followed by a chiral‐at‐ruthenium catalyzed cyclization to provide chiral cyclic carbonates in yields of up to 95 % and with up to 99 % ee. This new synthetic method is proposed to proceed through a nitrene‐mediated intramolecular C(sp3)−H oxygenation which includes an unusual 1,7‐hydrogen atom transfer within a ruthenium nitrene intermediate. The method is applicable to the synthesis of non‐racemic chiral mono‐, di‐ and trisubstituted cyclic alkylene carbonates. [ABSTRACT FROM AUTHOR]

Pyrrolidines are significant N‐heterocycles in medicinal chemistry and are among the top ten ring systems found in drug molecules. While simple derivatives are commercially available, densely decorated derivatives with precise stereochemical arrangements remain difficult to obtain. Methods for synthesizing multisubstituted pyrrolidines with nonadjacent stereocenters are particularly scarce. To bridge this gap, we report the stereoselective synthesis of remotely decorated, trisubstituted β‐prolines via Rh‐catalyzed C−H amination. The transformation proceeds well in the presence of various functionalities with exclusive anti‐selectivity. Carboxylic acids in the products serve as gateways for diverse downstream transformations. Furthermore, the combined experimental and computational study sheds lights on the origin of high diastereoselectivity. [ABSTRACT FROM AUTHOR]

Organic azides are a common functional group in polymer chemistry. Upon irradiation, they form nitrenes which are usually exploited for crosslinking based on their "universal" reactivity allowing insertion into nearby C–H bonds. Herein, it is demonstrated that polymer‐bound perfluorophenyl azide groups selectively form sulfoximines when irradiated in the presence of an excess of sulfoxide, without observable crosslinking. Poly(4‐azido‐2,3,5,6‐tetrafluorobenzyl methacrylate) (carrying an azide group in every repeat unit) is prepared through azide–para‐fluoro postpolymerization modification of a 2,3,4,5,6‐pentafluorobenzyl‐functional precursor. Samples of the azide‐functional polymer are irradiated (λmax = 254 nm) in dichloromethane in the presence of varying amounts of five different sulfoxides. Products are characterized by 1H and 19F NMR spectroscopy, Fourier transform infrared spectroscopy, size exclusion chromatography, and differential scanning calorimetry. Irradiations for 7 h with a 40–70‐fold molar excess of sulfoxides gave soluble products with azide‐to‐sulfoximine conversions of 89–96%. This first example of a selective nitrene‐based reaction in the polymer arena shows that sulfoxide solvents must be avoided if crosslinking is desired and provides access to novel sulfoximine‐functional materials. [ABSTRACT FROM AUTHOR]

The solvated iron(II) salt [Fe(NCMe) 6 ](BF 4) 2 (Me = methyl) is shown to be a bifunctional catalyst with respect to aziridination of styrene. The salt serves as an active catalyst for nitrene transfer from PhI NTs to styrene to form 2-phenyl- N -tosylaziridine (Ph = phenyl; Ts = tosyl, –S{O} 2 – p -C 6 H 4 Me). The iron(II) salt also acts as a Lewis acid in non-coordinating CH 2 Cl 2 solution, to catalyze heterolytic C N bond cleavage of the aziridine and insertion of dipolarophiles. The 1,3-zwitterionic intermediate is presumably supported by interaction of the metal dication with the anion, and by resonance stabilization of the carbocation. Nucleophilic dipolarophiles then insert to give a five-membered heterocyclic ring. The result is a two-step cycloaddition, formally [2 + 1 + 2], that is typically regiospecific, but not stereospecific. This reaction mechanism was confirmed by conducting a series of one-step, [3 + 2] additions of unsaturated molecules into pre-formed 2-phenyl- N -tosylaziridine, also catalyzed by [Fe(NCMe) 6 ](BF 4) 2. Relevant substrates include styrenes, carbonyl compounds and alkynes. These yield five-membered heterocylic rings, including pyrrolidines, oxazolidines and dihydropyrroles, respectively. The reaction scope appears limited only by the barrier to formation of the dipolar intermediate, and by the nucleophilicity of the captured dipolarophile. The bifunctionality of an inexpensive, earth-abundant and non-toxic catalyst suggests a general strategy for one-pot construction of heterocyclic rings, as demonstrated specifically for pyrrolidine ring formation. The solvated iron(II) salt [Fe(NCCH 3) 6 ](BF 4) 2 acts as a bifunctional catalyst for nitrene transfer from PhI NTs (Ph = C 6 H 5 and Ts = S{O} 2 C 6 H 4 - p -CH 3 to styrene in CH 3 CN and CH 2 Cl 2 solutions, and as a Lewis acid toward the product aziridine in the latter medium, which promotes heterolytic ring opening and insertion of dipolarophiles, including styrene, carbonyls and alkynes. [Display omitted] • The simple iron(II) salt [Fe(NCCH 3) 6 ](BF 4) 2 is a catalyst for aziridination of styrene. • The salt also acts as a Lewis acid in CH 2 Cl 2 to catalyze ring opening of aziridine to a 1,3-dipole. • Heterocycles are obtained from subsequent insertion of styrenes, carbonyl compounds, and alkynes. • [Fe(NCCH 3) 6 ](BF 4) 2 is a bifunctional catalyst for synthesis of five-membered heterocycles. [ABSTRACT FROM AUTHOR]

Photocatalytic generation of nitrenes and radicals can be used to tune or even control their reactivity. Photocatalytic activation of sulfonyl azides leads to the elimination of N2 and the resulting reactive species initiate C−H activations and amide formation reactions. Here, we present reactive radicals that are generated from sulfonyl azides: sulfonyl nitrene radical anion, sulfonyl nitrene and sulfonyl amidyl radical, and test their gas phase reactivity in C−H activation reactions. The sulfonyl nitrene radical anion is the least reactive and its reactivity is governed by the proton coupled electron transfer mechanism. In contrast, sulfonyl nitrene and sulfonyl amidyl radicals react via hydrogen atom transfer pathways. These reactivities and detailed characterization of the radicals with vibrational spectroscopy and with DFT calculations provide information necessary for taking control over the reactivity of these intermediates. [ABSTRACT FROM AUTHOR]

This study reports the development of Rh(II)-catalyzed N–N bond-forming reaction of amino acid derivatives or aliphatic amines to provide hydrazine derivatives through the combined use of Rh2 (esp)2 and [(3,4-dimethoxyphenyl)sulfonylimino]-2,4,6-trimethylphenyliodinane (3,4-(MeO)2 C6 H3 SO2 N=IMes). This is the first report of N–H amination of aliphatic amines with metal–nitrene species. [ABSTRACT FROM AUTHOR]

Herein, we report the stabilization of nitrene reagents as the source of a nitrogen atom to synthesize nitrogen‐incorporated R1LSi‐N←SiLR2 (1) [L=PhC(NtBu)2; R1=NTMS2, R2=NTMS]. Compound 1 is synthesized by reacting LSi(I)‐SiIL with 3.1 equivalents of Me3SiN3 at low temperature to afford a triene‐like structural framework. Whereas the reaction of the LSi(I)‐SiIL with 2.1 equivalents of Me3SiN3 at room temperature produced silaimine 2 with a central four‐membered Si2N2 ring which is accompanied by a silylene LSi and a cleaved silylene fragment. 1 further reacts with AgOTf at room temperature to yield compound 3 which shows coordination of nitrene to silver with the triflate salt. The compounds 1 and 2 were fully characterized by NMR, mass spectrometry, and X‐ray crystallographic analysis. The quantum mechanical calculations reveal that compounds 1 and 2 have dicoordinated monovalent N atoms having two active lone pairs of electrons. These lone pairs are stabilized by hyperconjugative interactions. [ABSTRACT FROM AUTHOR]

Creating a sustainable economy for plastics demands the exploration of new strategies for efficient management of mixed plastic waste. The inherent incompatibility of different plastics poses a major challenge in plastic mechanical recycling, resulting in phase-separated materials with inferior mechanical properties. Here, this study presents a robust and efficient dynamic crosslinking chemistry that effectively compatibilizes mixed plastics. Composed of aromatic sulfonyl azides, the dynamic crosslinker shows high thermal stability and generates singlet nitrene species in situ during solvent-free melt-extrusion, effectively promoting C─H insertion across diverse plastics. This new method demonstrates successful compatibilization of binary polymer blends and model mixed plastics, enhancing mechanical performance and improving phase morphology. It holds promise for managing mixed plastic waste, supporting a more sustainable lifecycle for plastics., (© 2024 Wiley‐VCH GmbH.)

Novel graphene-like nanomaterials with a non-zero bandgap are important for the design of gas sensors. The selectivity toward specific targets can be tuned by introducing appropriate functional groups on their surfaces. In this study, we use first-principles simulations, in the form of density functional theory (DFT), to investigate the covalent functionalization of a single-layer graphitized BC 6 N with azides to yield aziridine-functionalized adducts and explore their possible use to realize ammonia sensors. First, we determine the most favorable sites for physical adsorption and chemical reaction of methylnitrene, arising from the decomposition of methylazide, onto a BC 6 N monolayer. Then, we examine the thermodynamics of the [1 + 2]-cycloaddition reaction of various phenylnitrenes and perfluorinated phenylnitrenes para-substituted with (R = CO 2 H, SO 3 H) groups, demonstrating favorable energetics. We also monitor the effect of the functionalization on the electronic properties of the nanosheets via density of states and band structure analyses. Finally, we test four dBC 6 N to gBC 6 N substrates in the sensing of ammonia. We show that, thanks to their hydrogen bonding capabilities, the functionalized BC 6 N can selectively detect ammonia, with interaction energies varying from -0.54 eV to -1.37 eV, even in presence of competing gas such as CO 2 and H 2 O, as also confirmed by analyzing the change in the electronic properties and the values of recovery times near ambient temperature. Importantly, we model the conductance of a selected substrate alone and in presence of NH 3 to determine its effect on the integrated current, showing that humidity and coverage conditions should be properly tuned to use HO 2 C-functionalized BC 6 N-based nanomaterials to develop selective gas sensors for ammonia., (© 2024 IOP Publishing Ltd.)

Crosslinking polymers to form networks is a universal and routinely applied strategy to improve their stability and endow them with solvent resistance, adhesion properties, etc. However, the chemical crosslinking of common commercial polymers, especially for those without functional groups, cannot be achieved readily. In this study, we utilized low-molecular weight poly(glycidyl azide) (GAP) as polymeric crosslinkers to crosslink various commercial polymers via simple ultraviolet light irradiation. The azide groups were shown to decompose upon photo-irradiation and be converted to highly reactive nitrene species, which are able to insert into carbon-hydrogen bonds and thus crosslink the polymeric matrices. This strategy was demonstrated successfully in several commercial polymers. In particular, it was found that the crosslinking is highly localized, which could endow the polymeric matrices with a decent degree of crosslinking without significantly influencing other properties, suggesting a novel and robust method to crosslink polymeric materials.

Transition metal catalyzed nitrene transfers provide nitrogen containing compounds through C−H bond insertion, aziridination of olefins, and other types of reactions. Given the importance of these compounds in natural products and pharmaceuticals, tremendous efforts have been devoted to the development of efficient and reliable catalytic methods. In particular, the last decade has seen a remarkable progress in catalyst‐controlled chemoselective nitrene transfers, wherein different products can be obtained from a single substrate by the choice of catalyst. This Minireview covers this important and emerging area. We explain the principle of catalyst‐controlled synthesis, followed by highlighting literature examples for intra‐ and intermolecular reactions with an emphasis on the understanding of the nature of reactive intermediates and the strategy needed to realize selectivity. Finally, future directions are discussed based on the literature precedents. [ABSTRACT FROM AUTHOR]

The asymmetric synthesis of enantiopure pyrrolidines is reported via a streamlined strategy relying on two sequential C−H functionalizations of simple hydrocarbons. The first step is a regio‐ and stereoselective catalytic nitrene C−H insertion. Then, a subsequent diastereoselective cyclization involving a 1,5‐hydrogen atom transfer (HAT) from a N‐centered radical leads to the formation of pyrrolidines that can then be converted to their free NH‐derivatives. [ABSTRACT FROM AUTHOR]

Here, we report a metal‐free synthesis of anthranils from ortho‐carbonyl anilines using PhIO as a sole additive under ambient conditions. This methodology did not require any external additives and delivered anthranils in excellent yields with broad substrate scope. The mechanistic studies suggest that the reaction proceeds via in‐situ generation of iminoiodane leading to nitrene and a subsequent nucleophilic attack from oxygen of ortho‐carbonyl aniline on nitrene results in heterocyclization. [ABSTRACT FROM AUTHOR]

[Display omitted] Molecules containing C–N bonds are of paramount importance in a diverse array of organic-based materials, natural products, pharmaceutical compounds, and agricultural chemicals. Biocatalytic C–N bond-forming reactions represent powerful strategies for producing these valuable targets, and their significance in the field of synthetic chemistry has steadily increased over the past decade. In this review, we provide a concise overview of recent advancements in the development of C–N bond-forming enzymes, with a particular emphasis on the inherent chemistry involved in these enzymatic processes. Overall, these enzymatic systems have proven their potential in addressing long-standing challenges in traditional small-molecule catalysis. [ABSTRACT FROM AUTHOR]

The structure of [IrCl2(C58H51N3P4)]Cl·5.5CH3CN or [IrCl2(NHCHPh)(((dppm)C(N2dppm))-κ3P,C,P)]Cl·5.5CH3CN [3, dppm = bis(diphenylphosphino)methane; systematic name: dichlorido(1,1,3,3,7,7,9,9-octaphenyl-4,5-diaza-1,3λ5,7λ4,9-tetraphosphanona-3,5-dien-6-yl-κ2P1,P9)(phenylmethanimine-κN)iridium(III) chloride acetonitrile hemihendecasolvate], resulting from an oxygen-mediated cleavage of a triazeneylidenephosphorane ligand producing a diazomethylenephosphorane and a nitrene moiety, which in turn rearrange via a Staudinger reaction and a 1,2-hydride shift to the first title complex, involves a six-coordinate IrIII complex cation coordinated by a facial PCP pincer ligand, a benzaldimine and two chlorido ligands. The pincer system features a five- and a seven-membered ring, with the central divalent carbon of the PCP pincer ligand being connected to a phosphine and a diazophosphorane. The chlorido ligands are positioned trans to the central carbon atom and to the phosphorus donor of the seven-membered ring of the pincer system, respectively. A chloride ion serves as counter-ion for the monocationic complex. The structure of [IrI(C26H22N2P2)(C26H22P2)(C6H7N)]I(I3)·0.5I2·CH3OH·0.5CH2Cl2 or [IrI(NHCHPh)((dppm)C(N2)-κ2P,C)(dppm-κ2P,P′)]I(I3)·0.5I2·CH3OH·0.5CH2Cl2 {4, systematic name: (4-diazo-1,1,3,3,-tetraphenyl-1,3λ4-diphosphabutan-4-yl-κP1)iodido[methylenebis(diphenylphosphine)-κ2P,P′](phenylmethanimine-κN)iridium(III) iodide–triiodide–dichloromethane–iodine–methanol (2/2/1/1/2)}, accessed via treatment of the triazeneylidenephosphorane complex [Ir((BnN3)C(dppm)-κ3P,C,N)(dppm-κ2P,P′)]Cl with hydroiodic acid, consists of a dicationic six-coordinate IrIII complex, coordinated by a bidentate diazomethylenephosphorane, a benzaldimine, a chelating dppm moiety and an iodido ligand. The phosphorus atoms of the chelating dppm are trans to the central carbon atom of the diazomethylenephosphorane and the iodide ligand, respectively. Both an iodide and a triiodide moiety function as counter-ions. The acetonitrile solvent molecules in 3 are severely disordered in position and occupation. In 4, the I3− anion is positionally disordered (ratio roughly 1:1), as is the I− anion with a ratio of 9:1. The dichloromethane solvent molecule lies near a twofold rotation axis (disorder) and was refined with an occupancy of 0.5. Another disorder occurs for the solvent methanol with a 1:1 ratio.

A method for dirhodium-catalyzed C(sp3)–H amidation of N , N -dimethylanilines was developed. Chemoselective C(sp3)–H amidation of N -methyl group proceeded exclusively in the presence of C(sp2)–H bonds of the electron-rich aromatic ring. Site-selective C(sp3)–H amidation proceeded exclusively at the N -methyl group of N -methyl- N -alkylaniline derivatives with secondary, tertiary, and benzylic C(sp3)–H bonds α to a nitrogen atom. [ABSTRACT FROM AUTHOR]

Ruthenium-nitrene π bonds on Ru nanoparticles exhibit vibrational frequency around 1409 cm–1 as confirmed by isotopic labeling of 15N. In this manuscript, ruthenium (Ru) nanoparticles functionalized with nitrene ligands through the ruthenium-nitrene (Ru N) π bonds are explored. By synthesizing the nitrene ligands with and without 15N-labelling, Ru N π bonds on Ru nanoparticles are evidenced by experimental and theoretically calculated FTIR spectra. The coordination of nitrene ligands on Ru nanoparticles surface, the interfacial charge delocalization and the impact of nitrene ligands on the catalytic performance of Ru nanoparticles are further characterized by magic-angle spinning solid-state carbon nuclear magnetic resonance spectroscopy (13C NMR) of 13CO-adsorbed Ru nanoparticles, photoluminescence and the hydrogenation of styrene. [ABSTRACT FROM AUTHOR]

A readily available catalyst consisting of iron dichloride in combination with 1,10‐phenanthroline catalyzes the ring‐closing C−H amination of N‐benzoyloxyurea to form imidazolidin‐2‐ones in high yields. The C−H amination reaction is very general and applicable to benzylic, allylic, propargylic, and completely non‐activated aliphatic C(sp3)−H bonds, and it also works for C(sp2)−H bonds. The surprisingly simple method can be performed under open flask conditions. [ABSTRACT FROM AUTHOR]

Chiral β-amino alcohols are important building blocks for the synthesis of drugs, natural products, chiral auxiliaries, chiral ligands and chiral organocatalysts. The catalytic asymmetric β-amination of alcohols offers a direct strategy to access this class of molecules. Herein, we report a general intramolecular C(sp3)-H nitrene insertion method for the synthesis of chiral oxazolidin-2-ones as precursors of chiral β-amino alcohols. Specifically, the ring-closing C(sp3)-H amination of N-benzoyloxycarbamates with 2 mol% of a chiral ruthenium catalyst provides cyclic carbamates in up to 99% yield and with up to 99% ee. The method is applicable to benzylic, allylic, and propargylic C-H bonds and can even be applied to completely non-activated C (sp3)-H bonds, although with somewhat reduced yields and stereoselectivities. The obtained cyclic carbamates can subsequently be hydrolyzed to obtain chiral β-amino alcohols. The method is very practical as the catalyst can be easily synthesized on a gram scale and can be recycled after the reaction for further use. The synthetic value of the new method is demonstrated with the asymmetric synthesis of a chiral oxazolidin-2-one as intermediate for the synthesis of the natural product aurantioclavine and chiral β-amino alcohols that are intermediates for the synthesis of chiral amino acids, indane-derived chiral Box-ligands, and the natural products dihydrohamacanthin A and dragmacidin A. [ABSTRACT FROM AUTHOR]

The cobalt species PPh4[CoIII(TAMLred)] is a competent and stable catalyst for the sulfimidation of (aryl)(alkyl)‐substituted sulfides with iminoiodinanes, reaching turnover numbers up to 900 and turnover frequencies of 640 min−1 under mild and aerobic conditions. The sulfimidation proceeds in a highly chemoselective manner, even in the presence of alkenes or weak C−H bonds, as supported by inter‐ and intramolecular competition experiments. Functionalization of the sulfide substituent with various electron‐donating and electron‐withdrawing arenes and several alkyl, benzyl and vinyl fragments is tolerated, with up to quantitative product yields. Sulfimidation of phenyl allyl sulfide led to [2,3]‐sigmatropic rearrangement of the initially formed sulfimide species to afford the corresponding N‐allyl‐S‐phenyl‐thiohydroxylamines as attractive products. Mechanistic studies suggest that the actual nitrene transfer to the sulfide proceeds via (previously characterized) electrophilic nitrene radical intermediates that afford the sulfimide products via electronically asynchronous transition states, in which SET from the sulfide to the nitrene radical complex precedes N−S bond formation in a single concerted process. [ABSTRACT FROM AUTHOR]

The formation of hydrazinium salts by N−N bond formation has typically involved the use of hazardous and difficult to handle reagents. Here, mild and operationally simple conditions for the synthesis of hydrazinium salts are reported. Electrophilic nitrogen transfer to the nitrogen atom of tertiary amines is achieved using iodosylbenzene as oxidant and ammonium carbamate as the N‐source. The resulting process is highly chemoselective and tolerant to other functional groups. A wide scope is reported, including examples with bioactive molecules. Insights on the structure of hydrazinium salts were provided by X‐ray analysis. [ABSTRACT FROM AUTHOR]

Wir berichten über die ersten isolierbaren, elektronen‐präzisen Diborane(4) mit Azidresten: das acyclische 1,2‐Diazido‐1,2‐bis(dimethylamino)diboran(4) und eine Reihe cyclischer 1,4‐Diaryl‐2,3‐diazido‐1,4‐diaza‐2,3‐diborine (Aryl=Mesityl, 2,6‐Xylyl, 4‐Tolyl). Im Gegensatz zu den kürzlich von uns beschriebenen kurzlebigen Diboran(4)aziden, welche sich bereits bei Raumtemperatur spontan zersetzen, erweisen sich die hier dargestellten Moleküle als thermisch äußerst robust. So können diese kontrollierte Pyrolysereaktionen bei Temperaturen weit über 100 °C eingehen, ohne dass es zu deren explosionsartiger Zersetzung kommt. Überraschenderweise konnten in zwei Fällen nach der Pyrolyse komplexe Diazadiboretidine isoliert werden, welche formal die Dimerisierungsprodukte von endo‐cyclischen Boryliminoboranen darstellen. [ABSTRACT FROM AUTHOR]

Während sich direkte Nitren‐Insertionen in C‐H‐Bindungen zu einem wichtigen Werkzeug für die C‐N‐Bindungsknüpfung in der modernen organischen Chemie entwickelt haben, erfordert die Generierung von Nitren‐Zwischenstufen meist Übergangsmetall‐Katalysatoren, hohe Temperaturen, UV‐ oder Laserlicht. Wir berichten über eine milde Synthese von Carbazolen und verwandte Bausteine durch eine von sichtbarem Licht induzierte intramolekulare C‐H‐Aminierungs‐Reaktion. Ein wichtiger Vorteil dieser neuen Methode ist die Nutzung der reaktiveren Arylsulfilimine anstelle der korrespondierenden gefährlichen Azide. Verschiedene Katalysatoren und verschiedenste Lichtquellen wurden getestet. Die Reaktion kann breit angewendet werden und die Produktausbeuten sind generell hoch. Eine effiziente Synthese von Clausin C im Gramm‐Maßstab demonstriert die Anwendbarkeit und Skalierbarkeit dieser neuen Methode. [ABSTRACT FROM AUTHOR]

We report a three-component diamination of simple unactivated alkenes using an electrophilic nitrene source and amine nucleo-philes. The reaction provides rapid access to 1,2-vicinal diamines from terminal alkenes through a one-pot protocol. The transformation proceeds smoothly with excellent tolerance for a broad array of primary and secondary amines, affording the desired products in good yield and regioselectivity. The mechanism is proposed to proceed through a Rh(III)-catalyzed aziridination of alkenes with subsequent ring opening by primary or secondary amines. [ABSTRACT FROM AUTHOR]

Flash vacuum pyrolysis (FVP) of 2-acetyl-3-azido[1]benzothiophene at 300 °C provides 3-methyl [1]benzothieno[3,2-c]isoxazole (72%). At higher temperatures, the heteroindoxyl 1,2-dihydro[1]benzothieno[ 3,2-b]pyrrol-3-one was obtained in low yield (ca. 10%). The heteroindoxyl exists as a mixture of keto and enol forms in DMSO solution. Because of the easy oxidative dimerisation of these products to indigotin (and its heteroanalogues), such reactions are excellent examples of the synthetic advantages of FVP with the monomeric products conveniently generated under vacuum in a solvent -free, air-free environment. [ABSTRACT FROM AUTHOR]

Keywords: Catalysis; Conformation; Nitrene; RhodiumTwo structures of paddlewheel rhodium complexes displaying either syn or anti conformations are shown in the cover picture. Each of them stands on a separated podium, indicating that two conformations are not in an equilibrium and thus do not undergo interconversion. The conformational fixation has proven to be useful for the development of selective nitrene transfer catalysts, as demonstrated by Xinxin Tang, Hidetoshi Noda, and Masakatsu Shibasaki in their Research Article (e202311027)...By Xinxin Tang; Hidetoshi Noda and Masakatsu ShibasakiReported by Author; Author; Author [Extracted from the article]

Keywords: Catalysis; Conformation; Nitrene; RhodiumTwo structures of paddlewheel rhodium complexes displaying either syn or anti conformations are shown in the cover picture. Each of them stands on a separated podium, indicating that two conformations are not in an equilibrium and thus do not undergo interconversion. The conformational fixation has proven to be useful for the development of selective nitrene transfer catalysts, as demonstrated by Xinxin Tang, Hidetoshi Noda, and Masakatsu Shibasaki in their Research Article (e202311027)...By Xinxin Tang; Hidetoshi Noda and Masakatsu ShibasakiReported by Author; Author; Author [Extracted from the article]