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Trifluoromethylation‐based difunctionalization of alkenes provides a step‐economical route to CF3‐containing polyfunctionalized organics. New and scalable processes are highly desired in this field. Here, we report a simple and environmentally benign method for olefinic thiocyanotrifluoromethylation. Using PhICF3Cl as unique CF3 agent and NaSCN as the SCN source, the difunctionalization of alkenes selectively occurs on water at ambient condition. Mechanism studies suggest a radical process in which SCN anion is proposed to act as not only reductive initiator but also S‐nucleophile. All tested reactions are compatible with mono‐, di‐, tri‐, and tetra‐substituted alkenes and with high functional group tolerance. This method is also suitable for the selenocyanotrifluoromethylation of alkenes. Therefore, a sustainable platform has been established to synthesize valuable β‐trifluoromethylated thio(seleno)cyanates in a green way. [ABSTRACT FROM AUTHOR]

A simple chain‐extension reaction using diisocyanate as a chain extender was adopted to increase the molecular weight of low‐molecular‐weight (LMW) poly(lactic acid) (PLA) synthesized via direct polycondensation and to recover the molecular weight of commercial PLA after service life. The slow reaction between diisocyanate and the carboxylic acid terminus of PLA was successfully accelerated using a Mg(II) catalyst, affording a linear chain‐extended PLA (cePLA) connected through amide bonds. To increase the number of amide bonds, which exhibit higher thermal stability than the urethane bonds that are formed in the more common chain‐extension reactions between isocyanates and the hydroxy terminus of PLA, a telechelic LMW‐PLA having carboxylic acid groups at both termini was prepared. Subsequent reaction of this LMW‐PLA with diisocyanate in the presence of a Mg(II) catalyst afforded a cePLA with high molecular weight (Mw > 180 × 103 g/mol) and enhanced stability against thermal degradation, while showing identical mechanical properties and biodegradability as commercial PLA. [ABSTRACT FROM AUTHOR]

The kinetics of thermal electron attachment to methyl thiocyanate (CH3SCN), methyl isothiocyanate (CH3NCS), and ethyl thiocyanate (C2H5SCN) were measured using flowing afterglow-Langmuir probe apparatuses at temperatures between 300 and 1000 K. CH3SCN and C2H5SCN undergo inefficient dissociative attachment to yield primarily SCN− at 300 K (k = 2 × 10−10 cm3 s−1), with increasing efficiency as temperature increases. The increase is well described by activation energies of 0.17 eV (CH3SCN) and 0.14 eV (C2H5SCN). CN− product is formed at <1% branching at 300 K, increasing to ∼30% branching at 1000 K. Attachment to CH3NCS yields exclusively SCN− ionic product but at a rate at 300 K that is below our detection threshold (k < 10−12 cm3 s−1). The rate coefficient increases rapidly with increasing temperature (k = 6 × 10−11 cm3 s−1 at 600 K), in a manner well described by an activation energy of 0.51 eV. Calculations at the B3LYP/def2-TZVPPD level suggest that attachment to CH3SCN proceeds through a dissociative state of CH3SCN−, while attachment to CH3NCS initially forms a weakly bound transient anion CH3NCS−* that isomerizes over an energetic barrier to yield SCN−. Kinetic modeling of the two systems is performed in an attempt to identify a kinetic signature differentiating the two mechanisms. The kinetic modeling reproduces the CH3NCS data only if dissociation through the transient anion is considered. [ABSTRACT FROM AUTHOR]

Some sulfur-oxidizing bacteria playing an important role in global geochemical cycles utilize thiocyanate as the sole source of energy and nitrogen. In these bacteria the process of thiocyanate into cyanate conversion is mediated by thiocyanate dehydrogenases - a recently discovered family of copper-containing enzymes with the three‑copper active site unique among the other copper proteins. To get a deeper insight into the structure and molecular mechanism of action of thiocyanate dehydrogenases we isolated, purified, and comprehensively characterized an enzyme from the bacterium Pelomicrobium methylotrophicum. High-resolution crystal structures of the thiocyanate dehydrogenase in the free state and in the complexes with the transition state analog, thiourea, and the closest substrate analog, selenocyanate, unveiled the fine details of molecular events occurring at the enzyme active site. During the reaction thiocyanate dehydrogenase undergoes profound conformational change that affects the position of the constituent copper ions and results in the activation of the attacking water molecule. The structure of the enzyme complex with the selenium atom bridged in-between two copper ions was obtained representing an important transient intermediate. Structures of the complexes with inhibitors supplemented with quantum chemical calculations clarify the role of copper ions and refine molecular mechanism of catalysis by thiocyanate dehydrogenase., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Organophosphorus compounds are attractive and fruitful branch of chemistry that includes many tools and methods for easy research and targeted drugs formation. The reactions iso(thio)cyanates with organophosphorus reagents are studied. When N-phenyliminiovinylidenetriphenylphosphorane reacts with isocyanate produces azetiidinone, dihydropyrimidinedione and oxazinone derivatives. Moreover, isothiocyante can also react with the same reagent to give theitane, thiazinanethione and dithiane derivatives. On the other side, when iso(thio)cyanate reacts with the stabilized phosphonium ylides, the new phosphorane derivatives are obtained. In addition, the reaction of hexamethyltriaminophosphine with isocyanate and isothiocyanate in dry THF give carbamimidic acid and phosphonium betaine derivatives respectively. Moreover, thirteen of the newly synthesized products were screened in vitro for their activity against HepG-2, HCT116, and MCF-7 human cancer cell lines. [ABSTRACT FROM AUTHOR]

Unsubstituted and 1‐methyl‐substituted 1,3,4,8b‐tetrahydrodiazirino[3,1‐a]isoquinolines (diaziridines 1 and 2) demonstrate different reactivities toward aryl isocyanates and aryl isothiocyanates. Diaziridine 1 reacts with aryl isocyanates as a nucleophile to afford novel 1,5,6,10b‐tetrahydro[1,2,4]triazolo[5,1‐a]isoquinolines. The addition of a Lewis or Brønsted acid switches the reaction pathway, producing seven‐membered 2,3‐benzodiazepines. In reactions of diaziridine 1 with aryl isothiocyanates, unusual zwitterionic compounds – 2‐thioxo‐5,6‐dihydro‐2H‐[1,2,4]triazolo[5,1‐a]isoquinolin‐1‐ium‐3‐ides – and products of the addition of two molecules of diaziridine 1 to one molecule of aryl isothiocyanate are obtained. However, in reactions with aryl iso(thio)cyanates under heating or acid catalysis, diaziridine 2 is first converted into an azomethine imine, the 1,3‐dipolar cycloaddition of which to the dipolarophile produces substituted triazolo[5,1‐a]isoquinolin‐2(3H)‐(thi)ones. Proposed is a new method for azomethine imine generation from diaziridine 2 enabled by Brønsted acid catalysis. Antitumour activity of select compounds obtained was assayed to help guide future drug discovery efforts. [ABSTRACT FROM AUTHOR]

The synthesis and properties of silanes bearing a bulky carbazolyl substituent are described. Metathesis routes with different reagents under different conditions are required to obtain the compounds of the general formula RSi(X)2H and RSi(X)2All (X=Cl, N3, NCO, NCS, NH2, All=CH2CHCH2). The silanes were studied by XRD, NMR and IR spectroscopy and all findings were corroborated by DFT methods. [ABSTRACT FROM AUTHOR]

The employment of cyanato (OCN-) group in high oxidation state manganese cluster chemistry, in conjunction with carboxylate ions and the organic chelating/bridging ligand 2-(hydroxymethyl)pyridine (hmpH), is reported. The syntheses, crystal structures, and magnetochemical characterization are described for [Mn16O8(OR)4(OCN)4(O2CMe)12(hmp)6(ROH)2] (R = Me (1), Et (2)) and [Mn18O14(O2CR)18(hmp)4(hmpH)2(H2O)2] (R = Me (3), Et (4)). The 2:1:1:1 reactions of Mn(O2CMe)2·4H2O, hmpH, NaOCN and NEt3 in solvent MeOH or EtOH afford the isostructural complexes [Mn16O8(OR)4(OCN)4(O2CMe)12(hmp)6(ROH)2] (R = Me (1), Et (2)). The [Mn16(μ4-O)4(μ3-O)4(μ-OMe)4(μ3-OR)6(μ-OR)6]10+ core of representative complex 1 comprises a MnII4MnIII4 double-cubane subunit attached on either side to two symmetry-related MnIIMnIII3 defective dicubanes. A similar reaction of Mn(O2CR)2·4H2O, hmpH, NaOCN and NEt3, but in solvent MeCN, led instead to the formation of [Mn18O14(O2CR)18(hmp)4(hmpH)2(H2O)2] (R = Me (3), Et (4)). Compounds 3 and 4 are very similar to each other and can be described as a central [MnIII4(μ-O)6] rodlike subunit attached on either side to two symmetry-related [Mn7O9] subunits. Variable-temperature, solid-state dc and ac magnetic susceptibility studies revealed the presence of predominant antiferromagnetic exchange interactions in all compounds, and possible S = 2 or 1 (for 1 and 2) and S = 0 (for 3 and 4) ground state spin values. The combined results demonstrate the ability of cyanato groups to facilitate the formation of new polynuclear MnII/III complexes with structures different than these obtained from the use of the related azides.

The employment of cyanato (OCN-) group in high oxidation state manganese cluster chemistry, in conjunction with carboxylate ions and the organic chelating/bridging ligand 2-(hydroxymethyl)pyridine (hmpH), is reported. The syntheses, crystal structures, and magnetochemical characterization are described for [Mn16O8(OR)4(OCN)4(O2CMe)12(hmp)6(ROH)2] (R = Me (1), Et (2)) and [Mn18O14(O2CR)18(hmp)4(hmpH)2(H2O)2] (R = Me (3), Et (4)). The 2:1:1:1 reactions of Mn(O2CMe)2·4H2O, hmpH, NaOCN and NEt3 in solvent MeOH or EtOH afford the isostructural complexes [Mn16O8(OR)4(OCN)4(O2CMe)12(hmp)6(ROH)2] (R = Me (1), Et (2)). The [Mn16(μ4-O)4(μ3-O)4(μ-OMe)4(μ3-OR)6(μ-OR)6]10+ core of representative complex 1 comprises a MnII4MnIII4 double-cubane subunit attached on either side to two symmetry-related MnIIMnIII3 defective dicubanes. A similar reaction of Mn(O2CR)2·4H2O, hmpH, NaOCN and NEt3, but in solvent MeCN, led instead to the formation of [Mn18O14(O2CR)18(hmp)4(hmpH)2(H2O)2] (R = Me (3), Et (4)). Compounds 3 and 4 are very similar to each other and can be described as a central [MnIII4(μ-O)6] rodlike subunit attached on either side to two symmetry-related [Mn7O9] subunits. Variable-temperature, solid-state dc and ac magnetic susceptibility studies revealed the presence of predominant antiferromagnetic exchange interactions in all compounds, and possible S = 2 or 1 (for 1 and 2) and S = 0 (for 3 and 4) ground state spin values. The combined results demonstrate the ability of cyanato groups to facilitate the formation of new polynuclear MnII/III complexes with structures different than these obtained from the use of the related azides.

The marine natural product (-)-8,15-diisocyano-11(20)-amphilectene (1), isolated from the Caribbean sponge Svenzea flava, was used as scaffold to synthetize five new products, all of which were tested against laboratory strains of Plasmodium falciparum and Mycobacterium tuberculosis H37Rv. The scaffold contains two isocyanide units that are amenable to chemical manipulation, enabling them to be elaborated into a small library of sulfur and selenium compounds. Although most of the analogs prepared were less potent than the parent compound, 5 was nearly equipotent showing IC50 values of 0.0066 μM and 0.0025 μM, respectively, against two strains (Dd2 and 3D7) of the malaria parasite. On the other hand, when assayed against the tuberculosis bacterium, analogs 5 and 6 were found to be more potent than 1.

A three‐component domino approach for the synthesis of chroman‐spiroquinazolin(thi)ones is described. It involves a condensation of 2‐aminoacetophenones and iso(thio)cyanates followed by a hetero‐Diels‐Alder annulation with 2‐hydroxybenzyl alcohol derivatives. The reaction exhibits a broad substrate scope under a metal‐free catalytic condition. [ABSTRACT FROM AUTHOR]

Metal-catalyzed [2+2+2] cycloaddition is a powerful tool that allows rapid construction of functionalized 6-membered carbo- and heterocycles in a single step through an atom-economical process with high functional group tolerance. The reaction is usually regio- and chemoselective although selectivity issues can still be challenging for intermolecular reactions involving the cross-[2+2+2] cycloaddition of two or three different alkynes and various strategies have been developed to attain high selectivities. Furthermore, enantioselective [2+2+2] cycloaddition is an efficient means to create central, axial, and planar chirality and a variety of chiral organometallic complexes can be used for asymmetric transition-metal-catalyzed inter- and intramolecular reactions. This review summarizes the recent advances in the field of [2+2+2] cycloaddition. 1 Introduction 2 Formation of Carbocycles 2.1 Intermolecular Reactions 2.1.1 Cyclotrimerization of Alkynes 2.1.2 [2+2+2] Cycloaddition of Two Different Alkynes 2.1.3 [2+2+2] Cycloaddition of Alkynes/Alkenes with Alkenes/Enamides 2.2 Partially Intramolecular [2+2+2] Cycloaddition Reactions 2.2.1 Rhodium-Catalyzed [2+2+2] Cycloaddition 2.2.2 Molybdenum-Catalyzed [2+2+2] Cycloaddition 2.2.3 Cobalt-Catalyzed [2+2+2] Cycloaddition 2.2.4 Ruthenium-Catalyzed [2+2+2] Cycloaddition 2.2.5 Other Metal-Catalyzed [2+2+2] Cycloaddition 2.3 Totally Intramolecular [2+2+2] Cycloaddition Reactions 3 Formation of Heterocycles 3.1 Cycloaddition of Alkynes with Nitriles 3.2 Cycloaddition of 1,6-Diynes with Cyanamides 3.3 Cycloaddition of 1,6-Diynes with Selenocyanates 3.4 Cycloaddition of Imines with Allenes or Alkenes 3.5 Cycloaddition of (Thio)Cyanates and Isocyanates 3.6 Cycloaddition of 1,3,5-Triazines with Allenes 3.7 Cycloaddition of Aldehydes with Enynes or Allenes/Alkenes 3.8 Totally Intramolecular [2+2+2] Cycloaddition Reactions 4 Conclusion [ABSTRACT FROM AUTHOR]

Reaction of bis(pinacolato)diboron with (6-Dipp)CuOtBu generates a ring-expanded N-heterocyclic carbene supported copper(I) boryl, (6-Dipp)CuBpin. This compound showed remarkable stability and was characterised by NMR spectroscopy and X-ray crystallography. (6-Dipp)CuBpin readily dechalcogenated a range of heterocumulenes such as CO2, isocyanates and isothiocyanates to yield (6-Dipp)CuXBpin (X = O, S). In the case of CO2 catalytic reduction to CO is viable in the presence of excess bis(pinacolato)diboron. In contrast, in the case of iso(thio)cyanates, the isocyanide byproduct of dechalcogenation reacted with (6-Dipp)CuBpin to generate a copper(I) borylimidinate, (6-Dipp)CuC(＝NR)Bpin, which went on to react with heterocumulenes. This off-cycle reactivity gives selective access to a range of novel boron-containing heterocycles bonded to copper, but precludes catalytic reactivity. [ABSTRACT FROM AUTHOR]

The reaction of phenyl isocyanate with pyridoxal is carried out with the participation of hydroxymethyl and phenolic groups with the formation of dicarbamate derivatives. The reactions of pyridoxal azomethines with phenyl isocyanate, depending on the structure and the ratio of the starting reagents, lead to the formation of mono-, di- or tricarbamate derivatives. The product of addition of azomethine pyridoxal to phenyl isocyanate with the participation of a hydroxymethyl group was obtained. [ABSTRACT FROM AUTHOR]

This article sets forth the removal efficiency for cyanide compounds in a full-scale reverse osmosis system supplied with water coming from a co-precipitation chemical process. This test was carried out for a month and a half, with a 72% recovery rate using Dow Filmtec thin-film composite membranes, the MDS-41 8040 model in the first and second stages, and the MDS-42 8040 model in the third stage. The results showed removal efficiencies for ammonia at 92.71%, and thiocyanates at 91.76%. For WAD cyanide, the system did not achieve good removal efficiency (47.93%), probably due to its low molecular weight and low inlet concentration level (0.054 ppm); however, this value is lower than the Peruvian Environmental Quality Standard (<0.10 ppm). According to the results, the highest removal efficiency has been determined for cyanate compounds at an average value of 95.33%. The results have shown the best average removal efficiency for monovalent cyanide compounds of higher molecular weight (cyanates and thiocyanates) and by-products of the oxidation and hydrolysis process of cyanide compounds (ammonium ion), representing an overall average efficiency of 93.26%. This finally confirms that the rejection of components in reverse osmosis is related to molecular weight and ionic charge. [ABSTRACT FROM AUTHOR]

A copper-based catalytic technique for the regioselective ortho C-H cyanation of vinylarenes has been developed. This method provides an effective means for the selective functionalization of vinylarene derivatives. A copper-catalyzed cyanative dearomatization mechanism is proposed to account for the regiochemical course of this reaction.

Me3Si−X (X=CN, N3, OCN, and SCN) was treated with the Lewis acids GaCl3 and B(C6F5)3 in toluene yielding the desired adducts Me3Si−X→GaCl3 and Me3Si−X→B(C6F5)3. All synthesized adducts were isolated and completely characterized including single crystal structure elucidations. The different structures, thermodynamics of formation and charge transfer effects are discussed on the basis of experimental and theoretical data. [ABSTRACT FROM AUTHOR]

Me3Si−X (X=CN, N3, OCN, and SCN) was treated with the Lewis acids GaCl3 and B(C6F5)3 in toluene yielding the desired adducts Me3Si−X→GaCl3 and Me3Si−X→B(C6F5)3. All synthesized adducts were isolated and completely characterized including single crystal structure elucidations. The different structures, thermodynamics of formation and charge transfer effects are discussed on the basis of experimental and theoretical data. [ABSTRACT FROM AUTHOR]

We present the η3‐coordination of the 2‐phosphaethynthiolate anion in the complex (PN)2La(SCP) (2) [PN=N‐(2‐(diisopropylphosphanyl)‐4‐methylphenyl)‐2,4,6‐trimethylanilide)]. Structural comparison with dinuclear thiocyanate‐bridged (PN)2La(μ‐1,3‐SCN)2La(PN)2 (3) and azide‐bridged (PN)2La(μ‐1,3‐N3)2La(PN)2 (4) complexes indicates that the [SCP]− coordination mode is mainly governed by electronic, rather than steric factors. Quantum mechanical investigations reveal large contributions of the antibonding π*‐orbital of the [SCP]− ligand to the LUMO of complex 2, rendering it the ideal precursor for the first functionalization of the [SCP]− anion. Complex 2 was therefore reacted with CAACs which induced a selective rearrangement of the [SCP]− ligand to form the first CAAC stabilized group 15–group 16 fulminate‐type complexes (PN)2La{SPC(RCAAC)} (5 a,b, R=Ad, Me). A detailed reaction mechanism for the SCP‐to‐SPC isomerization is proposed based on DFT calculations. [ABSTRACT FROM AUTHOR]

Shock compression of two molded, carbon fiber-filled polymer composites was performed in gas gun-driven plate impact experiments at impact velocities up to ≈5 km/s. Hugoniot states for both composites were obtained from <5GPa to nearly 50GPa. The two materials contained a high fill percentage of chopped carbon fibers, bound by either phenolic or cyanate ester polymeric resins. Their dynamic responses were similar, although the 10wt.% difference of carbon fill produced measureable divergence in shock compressibility. The chopped carbon fibers in the polymer matrix led to moderately anisotropic shocks, particularly when compared with the more commonly encountered filament-wound carbon fiber-epoxy composites. A discontinuity, or cusp, was observed in the principal Hugoniot of both materials near 25GPa. We attribute the accompanying volume collapse to shock-driven chemical decomposition above this condition. Inert and reacted products equations of state were used to capture the response of the two materials below and above the cusp. [ABSTRACT FROM AUTHOR]

In this work, a reusable DNA sensing microchip was developed for detection of vomitoxin (deoxynivalenol, DON) in sorghum using Cd-based core-shell CdSe@CdS quantum dots (QDs) as promising electrochemiluminescence (ECL) emitter. The size-adjustable aqueous phase CdSe@CdS QDs were prepared through homogeneous method, exhibiting strong cathodic ECL emission with a central wavelength of 520 nm in S 2 O 8 2- coreactant. And gold nanoparticles-modified iron cobalt cyanide hydrate (Fe-Co-Au) was introduced as an accelerator to amplify the ECL signal. ECL signal was quenched after the formation of a double-stranded (dsDNA) S1-S2 by generating an electron transfer system between the emitter and ferrocene (Fc), which are modified on the aptamer (ssDNA S1) and its complement sequence (ssDNA S2), respectively. When the target DON is presence, the aptamer ssDNA S1 will bind to the DON and trigger the unbinding of double strands DNA and the release of the ssDNA S2, thus the signal can be generated. This approach offers a feasible method for the detection of DON within the range of 1 ng/mL to 200 ng/mL., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Polysaccharide-based vaccines cannot stimulate long-lasting immune response in infants due to their inability to elicit a T-cell-dependent immune response. This has been addressed using conjugation technology, where conjugates were produced by coupling a carrier protein to polysaccharides using different conjugation chemistries, such as cyanylation, reductive amination, ethylene diamine reaction, and others. Many glycoconjugate vaccines that are manufactured using different conjugation technologies are already in the market for neonates, infants and young children (e.g., Haemophilus influenzae type-b, Streptococcus pneumoniae and Neisseria meningitidis vaccines), and all of them elicit a T-cell dependent immune response. To manufacture glycoconjugate vaccines, the capsular polysaccharide is first activated by converting its hydroxyl groups to aldehyde-, cyanyl-, or cyanate ester groups, depending on the conjugation chemistry selected. The oxidized and reduced aldehyde functional groups of the polysaccharides are subsequently reacted with the amino groups of carrier protein by reductive amination to form a stable amide bond. In CDAP-based conjugation, the polysaccharide -OH groups are activated to form cyanyl-, or cyanate ester groups to react with the amino groups of carrier protein and forms an isourea bond. Understanding the extent of polysaccharide activation/modification is essential since it directly influences the molar mass of the conjugate, its stability, and the immunogenicity of the product. Reported methods are available to estimate the aldehyde groups of polysaccharides generated by reductive amination. However, no method is available to quantify the cyanyl or cyanate ester (-OCN) groups generated by cyanylation with 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP). We report a novel strategy using an O-phthalaldehyde (OPA) derivatization process followed by size-exclusion chromatography (SEC) high-performance liquid chromatography (HPLC) separation and UV detection. The cyanate ester groups on the activated polysaccharide directly reveal the extent of polysaccharide activation/modification and the residual activated groups in the purified conjugates. This method would be useful for conjugate vaccine manufacturing using CDAP chemistry., Competing Interests: Declaration of Competing Interest Authors declare no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Heme-copper oxygen reductases are terminal respiratory enzymes, catalyzing the reduction of dioxygen to water and the translocation of protons across the membrane. Oxygen consumption is inhibited by various substances. Here we tested the relatively unknown inhibition of cytochrome c oxidase (CcO) with isocyanate. In contrast to other more common inhibitors like cyanide, inhibition with cyanate was accompanied with the rise of a metal to ligand charge transfer (MLCT) band around 638 nm. Increasing the cyanate concentration furthermore caused selective reduction of heme a. The presence of the CT band allowed for the first time to directly monitor the nature of the ligand via surface-enhanced resonance Raman (SERR) spectroscopy. Analysis of isotope sensitive SERR spectra in comparison with Density Functional Theory (DFT) calculations identified not only the cyanate monomer as an inhibiting ligand but suggested also presence of an uretdion ligand formed upon dimerization of two cyanate ions. It is therefore proposed that under high cyanate concentrations the catalytic site of CcO promotes cyanate dimerization. The two excess electrons that are supplied from the uretdion ligand lead to the observed physiologically inverse electron transfer from heme a3 to heme a. [ABSTRACT FROM AUTHOR]

Vibrational energy transfer from the first excited state (2635 cm-1) of the O–D stretch of deuterated water (D2O) to the 0-1 transition (2075 cm-1) of the CN stretch of potassium selenocyanate (KSeCN) in their 2.5:1 liquid mixture was observed with a multiple-mode two dimensional infrared spectroscopic technique. Despite the big energy mismatch (560 cm-1) between the two modes, the transfer is still very efficient with a time constant of 20 ps. The efficient energy transfer is probably because of the large excitation coupling between the two modes. The coupling is experimentally determined to be 176 cm-1. An approximate analytical equation derived from the Landau–Teller formula is applied to calculate the energy transfer rate with all parameters experimentally determined. The calculation results are qualitatively consistent with the experimental data. [ABSTRACT FROM AUTHOR]

Evidence for ion pair formation in aqueous bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles (RMs) was obtained from infrared spectra of azide and cyanate with Li+, Na+, K+, and NH4+ counterions. The anions’ antisymmetric stretching bands near 2000 cm-1 are shifted to higher frequency (blueshifted) in LiAOT and to a lesser extent in NaAOT, but they are very similar to those in bulk water with K+ and NH4+ as the counterions. The shifts are largest for low values of wo=[water]/[AOT] and approach the bulk value with increasing wo. The blueshifts are attributed to ion pairing between the anions and the counterions. This interpretation is reinforced by the similar trend (Li+>Na+>K+) for producing contact ion pairs with the metal cations in bulk dimethyl sulfoxide (DMSO) solutions. We find no evidence of ion pairs being formed in NH4AOT RMs, whereas ammonium does form ion pairs with azide and cyanate in bulk DMSO. Studies are also reported for the anions in formamide-containing AOT RMs, in which blueshifts and ion pair formation are observed more than in the aqueous RMs. Ion pairs are preferentially formed in confined RM systems, consistent with the well established ideas that RMs exhibit reduced polarity and a disrupted hydrogen bonding network compared to bulk water and that ion-specific effects are involved in mediating the structure of species at interfaces. [ABSTRACT FROM AUTHOR]

Radiotherapy (RT) stands as a cornerstone in the clinical armamentarium against various cancers due to its proven efficacy. However, the intrinsic radiation resistance exhibited by cancer cells, coupled with the adverse effects of RT on normal tissues, often compromises its therapeutic potential and leads to unwanted side effects. This comprehensive review aims to consolidate our understanding of how radiosensitizers inhibit the thioredoxin (Trx) system in cellular contexts. Notable radiosensitizers, including gold nanoparticles (GNPs), gold triethylphosphine cyanide ([Au(SCN) (PEt 3 )]), auranofin, ceria nanoparticles (CONPs), curcumin and its derivatives, piperlongamide, indolequinone derivatives, micheliolide, motexafin gadolinium, and ethane selenide selenidazole derivatives (SeDs), are meticulously elucidated in terms of their applications in radiotherapy. In this review, the sensitization mechanisms and the current research progress of these radiosensitizers are discussed in detail, with the overall aim of providing valuable insights for the judicious application of Trx system inhibitors in the field of cancer radiosensitization therapy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

In view of the axial dimensional stability of the main loaded cylinder of the space camera, the thermal expansion characteristics of the carbon fibre M55J/cyanate ester (CE) composite were studied. In this paper, the coefficient of thermal expansion (CTE) of four kinds of carbon fibre composites used in aerospace are analysed and measured in both directions. The results show that the CTE of M55J/CE composite is negative, which cannot be achieved by carbon/epoxy composite. According to this characteristic, the layering mode of M55J/CE laminates was optimised, The CTE of M55J/CE laminates was analysed by the finite element method. Then the loaded cylinder was developed using the optimal ply program. Two different measuring methods, 'Heating blanket/Three-coordinate measurement' and 'High–low temperature chamber/submicrometer displacement detector measurement method' were proposed to measure the CTE of the loaded cylinder, and the advantages and disadvantages of the two measuring methods are also analysed. The test results were compared, which verified the credibility of the measurement method and data, The test results of 'High–low temperature chamber/Submicrometer displacement detector measurement method' were closer to the laminate, which laid the foundation for engineering applications. [ABSTRACT FROM AUTHOR]

An efficient, ruthenium(II)‐catalyzed, solvent‐free approach for the synthesis of 2‐aryloxypyridines with good to excellent yields has been developed by the reaction of 1,6‐diynes with aryl cyanates. This atom‐economical catalytic strategy offers a mild and practical approach to access a variety of such cycloadducts with excellent regioselectivities. The protocol was further extended to the synthesis of 2,2′‐ and 2,3′‐diaryloxybipyridines by the reaction of tetraynes with aryl cyanates. [ABSTRACT FROM AUTHOR]

This essay details the author's work with high-energy molecules based on sulfur or nitrogen, or both, which started with amateur rocket propellants like zinc dust and sulfur followed by experiments with the highly sensitive compounds nitrogen trichloride and fulminating gold. Research on the inorganic and organic fulminates and the isomeric cyanates led to detailed investigations of reactive intermediates generated by flash vacuum pyrolysis or photolysis, in particular nitrenes and carbenes derived from azides, diazo compounds, triazoles, and tetrazoles and characterized in low temperature matrices. This essay is an autobiographical survey of exciting and potentially fulminating chemistry in the author's laboratories since 1955 – all involving the elements nitrogen or sulfur or both. The graphic illustrates the ignition of the Zn+S rocket propellant. [ABSTRACT FROM AUTHOR]

A strong catalytic effect of 1.0 wt% ionic liquids (ILs) on kinetic parameters of dicyanate ester of bisphenol E (DCBE) polycyclotrimerization was evidenced, and structure-property relationships of resulting densely cross-linked cyanate ester resins (CERs) were investigated. Three different ILs with contrasted reactivity were employed as a catalysts: an aprotic IL, i.e. 1-octyl-3-methyl imidazolium tetrafluoroborate ([OMIm][BF4]), a protic IL, i.e. 2-(hydroxyethylamino) imidazolinium chloride ([HEAIm][Cl]), and a protic polymeric IL, i.e. poly(hexamethylene guanidine) toluene sulfonate ([PHMG][TS]). Both [HEAIm][Cl] and [PHMG][TS] were reactive towards DCBE monomer, whereas [OMIm][BF4] was chemically inert, as confirmed by Fourier Transform Infrared (FTIR) spectroscopy. Noticeably, the conversion (ac) of cyanate groups in the presence of ILs dramatically increased, and a significant dependence of ac values on IL chemical structure was found. The corresponding mechanisms of DCBE polycyclotrimerization in the presence of different ILs were proposed. All the CER/IL networks exhibited a high thermal stability inherent to neat CER, as shown by TGA, whereas unexpected significant changes of the viscoelastic characteristics for CER/IL networks compared to pure CER analogue were observed using DMTA. [ABSTRACT FROM AUTHOR]