![1-methyl-2-(methylsulfonyl)-1H-benzo[d]imidazole](/Databaselist/images/loading.webp)
17088-21-0Relevant academic research and scientific papers
A simple visual sensor with the potential for determining the concentration of fluoride in water at environmentally significant levels
Nishimura, Tomoki,Xu, Su-Ying,Jiang, Yun-Bao,Fossey, John S.,Sakurai, Kazuo,Bull, Steven D.,James, Tony D.
, p. 478 - 480 (2013)
We have developed a simple and robust fluorescence based boronic-acid molecular sensor for determining the concentration of fluoride in water at environmentally significant levels. The simplicity of the method and the ability to measure fluoride in water between 0.1 and 1.5 ppm is particularly noteworthy given the WHO requirements for detecting levels of fluoride in drinking water below 1.5 ppm.
Rapid and Visual Detection and Quantitation of Ethylene Released from Ripening Fruits: The New Use of Grubbs Catalyst
Sun, Mingtai,Yang, Xin,Zhang, Yuannian,Wang, Suhua,Wong, Ming Wah,Ni, Runyan,Huang, Dejian
, p. 507 - 513 (2019)
Herein, we report on fluorophore-tagged Grubbs catalysts as turn-on fluorescent probes for the sensitive detection and quantitation of ethylene, a plant hormone that plays a critical role in many phases of plant growth and fruit ripening. The ruthenium-based weak fluorescent probes were prepared handily through the metathesis reaction between the first-generation Grubbs catalyst and selected fluorophores that have high quantum yields and contain terminal vinyl groups. Upon exposure to ethylene, fluorescence enhancement was observed via the release of fluorophore from the probe. Our probe shows an excellent limit of detection for ethylene at 0.9 ppm in air and was successfully applied for monitoring ethylene released during the fruit-ripening process. Our work opens up a new avenue of application of Grubbs catalysts for bioanalytical chemistry of ethylene, which is critically important in plant biology, agriculture, and food industry.
Molecular engineering of pyrene carbazole dyes with a single bond and double bond as the mode of linkage
Unny, Divya,Kandregula, Ganapathi Rao,Sivanadanam, Jagadeeswari,Ramanujam, Kothandaraman
, p. 16511 - 16525 (2020)
Both carbazole and pyrene are electron-rich aromatic systems and are expected to be potential donors when used in a push-pull dye architecture in the field of DSSC technology. Herein, two novel pyrene-carbazole dyes bearing single bond (PC1) and double bond (PC2) linkers and cyano-acrylic acid as an acceptor were synthesized. The dye with a double bond spacer (PC2) in the presence of CDCA achieved an improved power conversion efficiency of 6.30% with a short circuit current of 11.59 mA cm-2, open circuit potential (VOC) of 0.80 V, and a fill factor of 0.68 under standard global AM 1.5G solar conditions. Cyclic voltammetry and density functional theory studies indicate that the incorporation of two donors improved the ease of oxidation of the dyes, which resulted in a high VOC. Despite having a rigid single bond, the charge transfer of the PC1 dye is found to be poor, which affected the photovoltaic performance. The dihedral angle measured at each joint of the optimized dye indicated that PC2 exhibits excellent intramolecular charge transfer due to the near planarity in the structure. Besides, the high electron lifetime in the excited state of PC2 makes it the best performer among the three dyes studied.
Synthesis and dye-sensitized solar cell application of polyolefinic aromatic molecules with pyrene as surface group
Rajakumar, Perumal,Visalakshi, Kathiresan,Ganesan, Shanmugam,Maruthamuthu, Pichai,Suthanthiraraj, Samuel Austin
, p. 951 - 956 (2011)
Synthesis of polyolefinic aromatic molecules with pyrene as the surface group, and their role as an additive in the redox couple of dye-sensitized solar cells, is described. The studies yield a promising power conversion efficiency of 5.27% with a short circuit current density of 6.50mAcm-2, an open circuit voltage of 0.60V, and a fill factor of 0.54 under 40mWcm--2 simulated air mass (A.M.) 1.5 illumination. Most importantly, the photocurrent responsivity increases with an increase in the number of pyrene units on the surface.
New Functional Polymers Prepared by Ring-Opening Metathesis Polymerization: Study of the Quenching of Luminescence of Pyrene End Groups by Ferrocene or Phenothiazine Centers in the Polymers
Albagli, D.,Bazan, G. C.,Schrock, R. R.,Wrighton, M. S.
, p. 10211 - 10216 (1993)
Emission from pyrene end-capped redox polymers is quenched relative to emission from 1-vinylpyrene, a structural model for the end group in the polymer.The redox polymers were prepared by ring-opening metathesis polymerization (ROMP) of norbornene derivatives containing ferrocene or phenothiazine, using catalysts of the type Mo(CH-t-Bu)(NAr)(O-t-Bu)2 (Ar = 2,6-diisopropylphenyl).The pyrene group was introduced by reactions of the living polymer with 1-pyrenecarboxaldehyde, thus producing polymers that are derivatives of 1-vinylpyrene.A ferrocene-containing homopolymer was prepared with 12 equiv of a ferrocene-containing monomer, followed by capping with pyrene, (1)12-pyrene, where pyrene emission is quenched by a factor of 30.Two phenothiazine-containing polymers were studied; a homopolymer prepared from 10 equiv of a phenothiazine-containing monomer followed by capping with pyrene, (2)10-pyrene, and a block copolymer formed from 10 equiv of a phenothiazine monomer, then 70 equiv of norbornene, (NBE), followed by capping with pyrene, (2)10(NBE)70-pyrene.In these polymers pyrene emission is quenched by a factor of 110 and 7, respectively.The quenching is proposed to occur via electron transfer from phenotiazine to the excited singlet state of pyrene and, depending on the structure of the polymer, by the formation of an exciplex with phenothiazine. (2)10-pyrene has a broad, featureless emission arising from excitation of the pyrene chromophore whose maximum is shifted > 6100 cm-1 to lower energy from the singlet energy of 1-vinylpyrene that is assigned to be emission from a pyrene/phenothiazine exciplex.The block coplymer (2)10(NBE)70-pyrene does not display this low-energy emission, nor do solutions containing the separate species 1-vinylpyrene and either N-methylphenolthiazine or the phenolthiazine-containing monomer, 2.
Laser Photolysis Studies on -Photocycloreversion and Phtoisomerization Reactions of trans- and cis-1,2-Di(1-pyrenyl)cyclobutane Dimers through Radical Ion Intermediates
Tsuchida, Akira,Yamamoto, Masahide,Nishijima, Yasunori
, p. 3402 - 3410 (1991)
Transient radical ion intermediates of -photocycloreversion and photoisomerization reactions of the 1-vinylpyrene (1) cyclobutane dimers, trans- and cis-1,2-di(1-pyrenyl)cyclobutanes (2t and 2c, respectively), were studied by nanosecond laser photolysis measurements; the reaction quantum yields were determined by photoproduct analysis.The excited singlet state of dimers 2t and 2c was quenched by an electron acceptor, 1,4-dicyanobenzene, with a diffusion-controlled rate in a polar acetonitrile solvent.The transient absorption spectra of the dimers in the system showed the formation of a dimer radical cation of pyrene chromophores, whose positive charge was delocalized in the two pyrene rings.The dimers were cleaved to form 1 through the dimer radical cation.By contrast, the formation of a dimer radical anion could not be observed in quenching by an electron donor, N,N-dimethyl-p-toluidine.The cleavage yield of the dimers from the anionic species was low.The decrease in the electronic density in the cyclobutane bond in the cationic state promotes the cycloreversion reaction of dimers.In the absence of an electron donor or acceptor in the nonpolar benzene solvent, the direct photocleavage of 2t and 2c to 1 through the csinglet excited state occurred efficiently, whereas in polar acetonitrile the cleavage was reduced to half by solvation of the excited states.A photocleavage of dimers also occurred in their triplet states.
Size-Induced Inversion of Selectivity in the Acylation of 1,2-Diols
Mayr, Stefanie,Zipse, Hendrik
supporting information, p. 18084 - 18092 (2021/12/02)
Relative rates for the Lewis base-catalyzed acylation of aryl-substituted 1,2-diols with anhydrides differing in size have been determined by turnover-limited competition experiments and absolute kinetics measurements. Depending on the structure of the anhydride reagent, the secondary hydroxyl group of the 1,2-diol reacts faster than the primary one. This preference towards the secondary hydroxyl group is boosted in the second acylation step from the monoesters to the diester through size and additional steric effects. In absolute terms the first acylation step is found to be up to 35 times faster than the second one for the primary alcohols due to neighboring group effects.
Methylenation for Aldehydes and Ketones Using 1-Methylbenzimidazol-2-yl Methyl Sulfone
Ando, Kaori,Oguchi, Mai,Kobayashi, Takahisa,Asano, Haruka,Uchida, Nariaki
, p. 9936 - 9943 (2020/09/04)
The methylenation reagent 1-methylbenzimidazol-2-yl methyl sulfone 2 reacts with various aldehydes and ketones in the presence of t-BuOK (room temperature, 1 h) in dimethylformamide to give the corresponding terminal alkenes generally in high yields. For sensitive substrates, the reaction is better carried out at low temperature using sodium hexamethyldisilazide in 1,2-dimethoxyethane. The byproduct is easily removed from the products, and the reaction conditions are mild and practical. Reagent 2 can be easily prepared from commercially available 2-mercaptobenzimidazole 5 in 95% yield without any expensive reagents.
Interfacial charge transport studies and fabrication of high performance DSSC with ethylene cored unsymmetrical dendrimers as quasi electrolytes
Ravivarma, Mahalingam,Kumar, Kaliamurthy Ashok,Rajakumar, Perumal,Pandurangan, Arumugam
, p. 717 - 726 (2018/07/23)
In this paper, authors focus the synthesis of conjugated unsymmetrical stilbenoid dendrimers by Heck and Horner-Wadsworth-Emmons coupling. In UV–visible absorption spectrum, the intensity of the absorption increases with increase in the generation of dendrimers. Further, bathochromic shift is observed on increasing the generation of the dendrimer from zero to first due to the greater widening of the energy gap between π-π* orbitals of the dendrimer system. Interfacial charge transport kinetics such as resistance, chemical capacitance and relaxation lifetime of the fabricated dye-sensitized solar cells (DSSC) are investigated using Nyquist and Bode phase plots by electrochemical impedance spectroscopy. Reduced electron relaxation lifetime (τe) of 1.83 ms (LiI + 7) and 1.04 ms (LiI + 8) provides efficient charge injection and thus reducing recombination process in the device. The performance of DSSC fabricated using unsymmetrical conjugated dendrimers with iodide electrolyte shows higher power conversion efficiency (PCE) than standard LiI based device. Two fold increments are achieved in PCE with first generation unsymmetrical dendrimers compared to their zeroth counterpart. The first generation unsymmetrical dendrimer 8 shows better PCE of 9.037% than all other synthesized dendrimers in the newly fabricated DSSC.
Selenium Blue-α and -β: Turning on the fluorescence of a pyrenyl fluorophore via oxidative cleavage of the Se-C bond by reactive oxygen species
Chen, Wei,Bay, Wan Ping,Wong, Ming Wah,Huang, Dejian
, p. 3843 - 3846 (2012/08/13)
Rapid oxidation of nonfluorescent pyrenyl-CH2SeAr (Ar = o-nitrophenyl) by hypochlorite yielded pyrenyl-CH2Cl and pyrenyl-CH2OH and turns on blue fluorescence, while slow oxidation of pyrenyl-CH2SeAr with excess
