17088-21-0Relevant articles and documents
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.
-
Flowers,Nichols
, p. 3104 (1949)
-
Tanikawa et al.
, p. 2719 (1968)
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.
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.
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.
