An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
... A carbazole-incorporated photochromic radical complex is synthesized. The long-wavelength photosensitivity of the photochromic reaction of the molecule is enhanced up to ∼580 nm by substituting a triphenylamine group into the 3-position of the carbazole moiety. These photochromic reactions are investigated by subpicosecond-to-microsecond transient absorption measurements. ...
... The novel turn-on fluorescent chemosensors for silver ion based on nicotinonitriles, containing a tricyanobutadiene moiety (tricyanopyridine, TCPy) were developed. The enchantment of fluorescent emission can be observed by naked eye, even in the presence of interference cations. The binding mode turned out to be a 1: 1 ratio as determined using Job’s plot. ...
Anindita Mukherjee; Alexey A. Akulov; Sougata Santra; Mikhail V. Varaksin; Grigory A. Kim; Dmitry S. Kopchuk; Olga S. Taniya; Grigory V. Zyryanov; Oleg. N. Chupakhin
... 2,7-Diazapyrenes are promising azaaromatic scaffolds with a unique structural geometry and supramolecular properties. This core moiety and its derivatives with some N-methyl cations like N-methyl-2,7,-diazapyrenium, and N,N′-dimethyl-2,7-diazapyrenium attract special attention due to their challenging photophysical properties, especially in the context of interactions with DNA and some of its mono ...
... Chiral rhodium(iii)–azobenzene complexes that are able to intercalate into DNA were developed. Upon light exposure, the azobenzene moiety of the metal complexes can photoisomerize from the trans-form to the cis-form, and strongly stabilize the DNA double-helix and modulate DNA transcription. This study presents the first example of metal-based photoswitchable DNA molecular locks. ...
... The catalytic asymmetric synthesis of borylated 3-hydroxyoxindoles by addition of gem-diborylalkanes to isatins is disclosed. Chiral 3-hydroxyoxindoles bearing two contiguous stereogenic centers were produced in up to >20:1 dr and 99% ee. The synthetic utility of the corresponding products is presented through several transformations of the boryl moiety. This report provides an efficient strategy ...
... The gem-difluoroalkene moiety is an ideal carbonyl bioisostere in medicinal chemistry, but efficient synthesis of β-gem-difluoroalkene esters remains challenging so far. Herein, we disclose a photoredox-catalyzed allylic defluorinative alkoxycarbonylation of trifluoromethyl alkenes enabled by intermolecular alkoxycarbonyl radical addition. A wide variety of alcohol oxalate derivatives were amenabl ...
... With the aim to enhance the photovoltages and efficiencies of dye sensitized solar cells (DSSCs) based on porphyrin dyes, a dialkoxy-substituted highly twisted tetraphenylethylene (TPE) moiety has been introduced into the donor unit of a porphyrin dye to suppress dye aggregation and charge recombination. Thus, based on our previously reported porphyrin dye XW43, a dialkoxy-TPE moiety has been intr ...
moieties, etc ; allylation; diastereoselectivity; skeleton; Show all 4 Subjects
Abstract:
... Herein, the synthesis of 6,7-benzene-fused tropane derivatives from isoindoline-aminal hybrid compound has been reported. In the present synthetic study, ring-closing metathesis (RCM) was employed to construct the 6,7-benzene-fused tropene skeleton. To obtain the desired cis-1-allyl-3-stylylisoindoline precursor for the RCM reaction, the diastereoselective aza-Hosomi-Sakurai allylation and functio ...
... Previous studies have proved that the characteristic galloyl moiety in polyphenols is crucial for their biological activities. However, whether the presence of the galloyl moiety in the structure of polyphenols has a great contribution to their inhibition of adipogenic differentiation is not clear. Therefore, in this study, seven polyphenols with different galloylation degrees were chosen for expl ...
... We report here a new double-cage endohedral Ge cluster, [Co₂@(Ge₁₇Ni)]⁴⁻, fused through two [Co@(Ge₉Ni)] moieties with a shared Ni–Ge edge. This ternary Co–Ge–Ni species not only represents the first double-cage example of an 18-vertex Zintl cluster, but also fills in the missing link of the edge fusion model in the double-cage systems. ...
moieties, etc ; chemical communication; methodology; rhodium; Show all 4 Subjects
Abstract:
... A unique method for the synthesis of substituted 1-naphthols by a rhodium(ii)-catalysed ring-expansion reaction of 2-triazolyl-1-indanone derivatives is reported. 1,2-Acyl migration occurs with an intermediate α-imino rhodium carbenoid generated from the triazolyl moiety. ...
moieties, etc ; alkenes; benzene; derivatization; nitrogen; Show all 5 Subjects
Abstract:
... Catalytic imidation using NFSI as the nitrogen source has become an emerging tool for oxidative carbon–nitrogen bond formation. However, the less than ideal benzenesulfonimide moiety is incorporated into products, severely detracting its synthetic value. As a solution to this challenge, we report herein the development of a novel N-fluorinated imide, N-fluoro-N-(fluorosulfonyl)carbamate (NFC), by ...
moieties, etc ; agrochemicals; ambient temperature; clofibrate; Show all 4 Subjects
Abstract:
... Trifluoroethylthio group (SCH₂CF₃) is a key functionality in several pharmaceutical and agrochemical compounds, the methods for the installation of the 2,2,2-trifluoroethylthio group are sought after. Herein, we report a copper-catalyzed trifluoroethylthiolation reaction of S-(2,2,2-trifluoroethyl) benzenesulfonothioates and phenylboronic acids at room temperature. The reaction achieved the insert ...
moieties, etc ; electrochemistry; hydrogen; quinoline; sodium; Show all 5 Subjects
Abstract:
... An efficient and green electrochemical N-ortho-selective difluoromethylation method of various quinoline and isoquinoline N-oxides has been developed. In this method, sodium difluoromethanesulfinate (HCF₂SO₂Na) was used as the source of the difluoromethyl moiety, and various N-ortho-selective difluoromethylation quinoline and isoquinoline N-oxides were obtained in good to excellent yields under a ...
moieties, etc ; cross-coupling reactions; hydrazides; oxygen; xanthenes; Show all 5 Subjects
Abstract:
... A straightforward strategy for direct incorporation of sulfonyl units into a xanthene moiety for accessing xanthen-9-sulfone derivatives in good to excellent yields has been established via metal-free radical–radical cross-coupling reaction of xanthenes and sulfonyl hydrazides. Using easily accessible starting materials, this methodology proceeds efficiently with a high degree of functional group ...
moieties, etc ; catalysts; coumarins; fluorescence; oximes; photoluminescence; pyridones; Show all 7 Subjects
Abstract:
... In the presence of a copper catalyst, a series of oximes undergo deconstructive insertion into coumarins to afford structurally interesting dihydrobenzofuran-fused pyridones in moderate to good yields with good functional group compatibility. The reaction likely involves a radical relay annulation, leading to the ring opening of the lactone moiety of the coumarins, and simultaneous formation of th ...
moieties, etc ; chitosan; hydrophilicity; hydrophobicity; molecular weight; solvents; Show all 6 Subjects
Abstract:
... Despite significant advances in the field, quantitative post-polymer modification of chitosan, specifically attaching diverse hydrophobic moieties with experimentally predefined (via the ratio of reagents) degree of functionalization remain extremely challenging. In this context, we report our studies towards the use of green and efficient azetidinium-amine reactions to prepare a library of modifi ...
moieties, etc ; aqueous solutions; blood serum; fluorescence; formaldehyde; Show all 5 Subjects
Abstract:
... Formaldehyde is an abundant contaminant in food and environments causing various diseases. Thus, the development of fast, simple, and selective formaldehyde detection is of great interest. Herein, novel quinolizinium-based fluorescent probes were designed based on a 2-aza-Cope rearrangement reaction and showed high selectivity to formaldehyde by fluorescence emission shift. We successfully reduced ...
moieties, etc ; cycloaddition reactions; glass; irradiation; lamps; stereoselectivity; Show all 6 Subjects
Abstract:
... Irradiation of 1-acylindole derivatives that possess a vinylcyclopropane moiety at the end of the acyl side chain by a high-pressure mercury lamp through Pyrex glass under sensitization of an aromatic ketone gave the corresponding cyclised products stereoselectively in high yields. The distribution of the products was highly dependent on the substituents on the cyclopropane ring. In the case of a ...
moieties, etc ; absorption; energy; fluorescein; organic chemistry; xanthenes; Show all 6 Subjects
Abstract:
... V-shaped xanthene dyes capable of predicting absorption and emission wavelengths are described. These dyes were synthesized by bridging a xanthene ring and an aryl moiety of fluorescein through ether covalent bonds. These dyes showed longer absorption and emission wavelengths than those of the parent fluorescein. Furthermore, substituents introduced on the aryl moiety mainly affected the lowest un ...