Tighten your belt: [12]Cycloparaphenylene, the sidewall segment of a carbon nanotube (see picture), has been synthesized in selective manner through stepwise palladium-catalyzed coupling reactions. The synthesis capitalizes on ability cis-1,4-dihydroxycyclohexane-1,4-diyl unit to attenuate build-up strain energy during macrocyclization. Detailed facts importance specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or typeset. They...

Click makes MICs: A short modular synthesis allows the preparation of novel stable heterocycles that feature a lone pair electrons on carbon center. The donor properties these mesoionic compounds are greater than those classical N-heterocyclic carbenes; they accessible by deprotonation corresponding conjugate acids using comparatively mild bases.

A CF3-BODIPY forms strongly luminescent aggregates, which contrasts with the quenched condensed-phase photophysics that are typical for BODIPY dyes. Examination of properties these aggregates – narrow red-shifted absorption and emission bands, minimal Stokes shift increased fluorescence rate constants solid-state packing dye establish as first structurally characterized genuine J-aggregate.

A new fluorescent turn-on probe (3) for the selective sensing and bioimaging of thiols is reported. In aqueous buffer solutions at physiological pH, cleave 2,4-dinitrobenzenesulfonyl group to release red-emissive donor−acceptor fluorophore (4). The displays excellent immunity interference from nitrogen oxygen nucleophiles imaging in living cells demonstrated.

The formal cycloaddition between 1,3-diaza-2-azoniaallene salts and alkynes or alkyne equivalents provides an efficient synthesis of 1,3-diaryl-1H-1,2,3-triazolium salts, the direct precursors 1,2,3-triazol-5-ylidenes. These N,N-diarylated mesoionic carbenes (MICs) exhibit enhanced stability in comparison to their alkylated counterparts. Experimental computational results confirm that these MICs act as strongly electron-donating ligands. Their increased allows for preparation ruthenium...

We developed a colorimetric and fluorescent turn-on carbon dioxide sensor that relies on polydiacetylene, PDA-1, functionalized with amines imidazolium groups. The pendant react CO2 under basic conditions to form carbamoate anions, which partially neutralize the polymer's positive charges, inducing phase transition. PDA-1 allows for selective sensing of high sensitivity, down atmospheric concentrations. Naked-eye detection is accomplished either in water solutions or solid state electrospun...

Abstract N‐Heterocyclic carbene (NHC) boranes undergo oxidative hydrolysis to give imidazolium salts with excellent kinetic selectivity for HOCl over other reactive oxygen species (ROS), including peroxides and peroxynitrite. Selectivity results from the electrophilic oxidation mechanism of NHC boranes, which stands in contrast nucleophilic arylboronic acids ROS. The change polarity that accompanies conversion can control formation emissive excimers, forming basis design first fluorescence...

Den Gürtel enger schnallen: [12]Cycloparaphenylen, das Wandsegment einer Kohlenstoffnanoröhre (siehe Bild), wurde mithilfe wiederholter palladiumkatalysierter Kupplungsreaktionen selektiv synthetisiert. Die Synthese profitiert von der Fähigkeit cis-1,4-Dihydroxycyclohexan-1,4-diyl-Einheit, dem Aufbau Spannungsenergie während Makrocyclisierung entgegenzuwirken. Detailed facts of importance to specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not...

Abstract A family of organic chromophores that, like pyrene, forms emissive excimers is reported. Their chemical and photophysical properties are superior to pyrene for the design chemo‐ biosensors. Unlike hydrophobic which requires excitation by cell‐damaging UV irradiation, these polar dyes absorb strongly in visible range, their emit brightly red far‐red region electromagnetic spectrum. The intensity emission signal greatly increased upon formation a preassociated dimer that triggered...

4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) derivatives bearing varied substituents at the meso position (i.e., CF3 , CH3 COOR, CHO, CN, Cl, iPr) were synthesized to elucidate structure-property relationships that give rise emissive J-aggregates. Several new BODIPY can be added previously reported 1,3,5,7-tetramethyl-8-trifluoromethyl derivative list of those forming J-aggregates, in addition other dyes are solid state without

Direct metalation of bis(1,2,3-triazolium) salts affords mononuclear rhodium(I) complexes, which feature a 1,4-bidentate bis(1,2,3-triazol-5-ylidene) (i-bitz) ligand. The topology the ligand is similar to that 2,2′-bipyridines (bpy) and their congeners, as well bis(1,2,4-triazol-5-ylidenes) (bitz). As former, but in contrast latter, free i-bitz can be isolated, paves way for various applications.

Fluorescence-based amine-reactive dyes are highly valuable for the sensing of amines and labeling biomolecules. Although it would be desirable, large changes in emission spectra intensity seldom accompany conjugation known to their target molecules. On contrary, amide bond formation between pentafluorophenyl (2-PFP) succinimidyl (2-NHS) esters meso-carboxyBODIPY results significant maxima (Δλ: 70–100 nm) (up 3000-fold), enabling fast (down 5 min) selective fluorogenic detection amines, amino...

The fluorogenic probe o-OH is able to detect and quantify organophosphorus nerve agent mimics in solution the vapor phase following immobilization on a solid substrate, making system suitable candidate for field detection of chemical warfare agents. Detection achieved by suppression internal rotation upon phosphorylation reactive phenolate, resulting large fluorescence "turn-on" response.

The naphthoimidazolium borane 4 is shown to be a selective probe for HOCl over other reactive oxygen species. Unlike boronate–reactive species (ROS) fluorogenic probes that are oxidized by through nucleophilic borono-Dakin oxidation mechanism, distinguished its electrophilic mechanism involving B–H bond cleavage. Two-photon microscopy experiments in living cells and tissues with the demonstrate monitoring of endogenous generation changes concentrations generated endoplasmic reticulum during...

H/D exchange at formyl groups is the most direct approach for synthesis of deuterated aldehydes. Platinum-group metal complexes have been employed to catalyze this transformation, with significant substrate scope limitations. Although N-heterocyclic carbenes can also activate C–H bond aldehydes through formation Breslow intermediates, benzoin condensation and other C–C-bond-forming pathways so far outpaced synthetically useful exchange. Investigation reaction 1,2,3-triazolylidenes has...

Conjugated polymers often display a decrease of fluorescence efficiency upon aggregation due in large part to enhanced interpolymer interactions that produce weakly emissive species generally described as having excimer-like character. We have found poly(phenylene ethynylene)s with fused pendant [2.2.2] ring structures alkene bridges substituted two ester groups function give highly emissive, broad, and red-shifted emission spectra the solid state. To best understand origin this new...

Heterocyclic monomers based on 2,1,3-benzooxadiazole and 2,1,3-benzothiadiazole bearing solubilizing side chains have been synthesized in high yields over three steps from readily available starting materials. The are efficiently cross-coupled with diynes bis(boronates) to afford molecular weight luminescent poly(arylene ethynylene)s polyfluorenes that exhibit red-shifted absorption emission maxima, greater solubility, reduced aggregation.

Mit einem Klick zu MICs: Eine kurze modulare Synthese führt neuartigen stabilen Heterocyclen mit freien Elektronenpaar an Kohlenstoffzentrum. Diese mesoionischen Verbindungen sind bessere Donoren als klassische N-heterocyclische Carbene, und sie durch Deprotonierung der konjugierten Säuren vergleichsweise milden Basen zugänglich. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents peer-reviewed, but not copy-edited or typeset. They...

The synthesis of a ruthenium complex containing an N-heterocylic carbene (NHC) and mesoionic (MIC) is described wherein addition Brønsted acid results in protonolysis the Ru–MIC bond to generate extremely active metathesis catalyst. Mechanistic studies implicated rate-determining protonation step generation metathesis-active species. activity NHC/MIC catalyst was found exceed those current commercial catalysts.

The meso-oxime-substituted-1,3,5,7-tetramethyl BODIPY (1-oxime) was developed into a colorimetric and fluorogenic probe to selectively detect quantify phosgene. fast (<10 s) sensitive (LOD = 0.09 ppb) phosgene detection is achieved by the conversion of meso-oxime meso-nitrile, resulting in large fluorescence turn-on response. utility 1-oxime established for visual solution practical solid-state platform, making it suitable candidate on-site monitoring gas exposure workplace.

Simple aromatic compounds like benzene are abundant feedstocks, for which the preparation of derivatives chiefly begins with electrophilic substitution reactions or, less frequently, reductions. Their high stability makes them particularly reluctant to participate in cycloadditions under ordinary reaction conditions. Here, we demonstrate exceptional ability 1,3-diaza-2-azoniaallene cations undergo formal (3 + 2) unactivated below room temperature, providing thermally stable dearomatized...

A Ni(cod)2/IPr catalyst promotes the intermolecular 1,2-addition of arylboronate esters to unactivated aldehydes and ketones. Diaryl, alkyl aryl, dialkyl ketones show good reactivity under mild reaction conditions (≤80 °C, nonpolar solvents, no strong base or acid additives). dramatic ligand effect favors either carbonyl addition (IPr) C−OR cross-coupling (PCy3) with aryl ether substrates. Ni(0)/Ni(II) catalytic cycle initiated by oxidative cyclization substrate is proposed.