New values of molecular extinction coefficient and specific rotation for cyanobacterial toxin cylindrospermopsin

Toxicon ◽  
2008 ◽  
Vol 51 (4) ◽  
pp. 717-719 ◽  
Author(s):  
Tomoharu Sano ◽  
Sachiko Kikuchi ◽  
Takuya Kubo ◽  
Hiroo Takagi ◽  
Ken Hosoya ◽  
...  
Keyword(s):  
Extinction Coefficient ◽  
Specific Rotation ◽  
Cyanobacterial Toxin ◽  
Molecular Extinction Coefficient

Disubstituted hydroxamic acids and the determination of vanadium

1968 ◽  
Vol 46 (2) ◽  
pp. 327-330 ◽  
Author(s):  
R. M. Cassidy ◽  
D. E. Ryan
Keyword(s):  
Extinction Coefficient ◽  
Metal Chelate ◽  
Visible Region ◽  
Hydroxamic Acids ◽  
Molecular Extinction Coefficient ◽  
Sensitivity Increase ◽  
Chelate Rings

A number of disubstituted hydroxamic acids were investigated as possible replacements for benzoylphenylhydroxylamine in the determination of vanadium; none is superior. At 378 mμ., p-phenylazobenzoylphenylhydroxylamine shows a marked sensitivity increase but selectivity is poor. In the visible region, there is an increase in molecular extinction coefficient as the reagent π system is extended; how ever, complete coplanarity of the aromatic and metal chelate rings is not possible and the increase is not large enough to be of much practical value.

Polyethyleneoxide-capped phthalocyanines: limiting phthalocyanine aggregation to dimer formation

2001 ◽  
Vol 05 (07) ◽  
pp. 582-592 ◽  
Author(s):  
D. D. DOMINGUEZ ◽  
A. W. SNOW ◽  
J. S. SHIRK ◽  
R. G. S. PONG
Keyword(s):  
Absorption Coefficient ◽  
Extinction Coefficient ◽  
Synthesis And Characterization ◽  
Lead Compound ◽  
Dimer Formation ◽  
Metal Free ◽  
Optical Limiter ◽  
532 Nm ◽  
Molecular Extinction Coefficient

The synthesis and characterization of a soluble metal-free polyethyleneoxide-capped phthalocyanine and the corresponding lead compound are described. This phthalocyanine was designed to allow the formation of dimers but to inhibit formation of higher aggregates. The monomer/dimer equilibrium constant in chloroform solutions is 750 ± 20 l mol -1. No evidence for higher aggregates was found. The molecular extinction coefficient of the metal-free polyethyleneoxide-capped phthalocyanine in chloroform is one of the lowest known (2.5 × 104 l mol -1 cm -1). The lead-substituted material was demonstrated to be a reverse saturable absorber from 532 nm to about 610 nm. It possesses a large nonlinear absorption coefficient in the visible and is a promising optical limiter material.

XXXVI.—The Absorption of Light by Inorganic Salts. No. I.: Aqueous Solutions of Cobalt Salts in the Infra-Red

1912 ◽  
Vol 31 ◽  
pp. 521-529 ◽  
Author(s):  
R. A. Houstoun
Keyword(s):  
Aqueous Solutions ◽  
Present Article ◽  
Extinction Coefficient ◽  
Accurate Determination ◽  
Visible Spectrum ◽  
Inorganic Salts ◽  
Absorption Of Light ◽  
Infra Red ◽  
Molecular Extinction Coefficient

The present article is intended to be the first of a series on the absorption of light by solutions of inorganic salts of different elements. With a few scattered exceptions all the work hitherto done on the absorption spectra of inorganic salts has been merely qualitative and has been confined to the visible spectrum. Kayser in his Spectroscopie, vol. iii. p. 45, states that in this field there is work for years and for numerous observers. E. C. C. Baly states in his Spectroscopy, p. 407, that not much is known about the absorption of light in inorganic salts. Merely for its own sake, then, an accurate determination of the molecular extinction coefficient for as many salts under as many different conditions of temperature and concentration, and for as many wave-lengths as possible, would be very valuable.

Synthesis and Characterization of ROSA Dye - A Rhodamine B-type Fluorophore, Suitable for Bioconjugation and Fluorescence Studies in Live Cells

2019 ◽  
Vol 26 (10) ◽  
pp. 758-767
Author(s):  
Vicente Rubio ◽  
Vijaya Iragavarapu ◽  
Maciej J. Stawikowski
Keyword(s):  
Quantum Yield ◽  
Cancer Cells ◽  
Fluorescent Probe ◽  
Extinction Coefficient ◽  
Rhodamine B ◽  
Solid Phase ◽  
Total Yield ◽  
Molar Extinction Coefficient ◽  
Αvβ3 Integrin ◽  
Αvβ3 Integrins

Background: Herein we report the multigram-scale synthesis, characterization and application of a rhodamine B-based fluorophore (ROSA) suitable for fluorescent studies in biological applications. This fluorophore is devoid of rhodamine spirolactone formation and furthermore characterized by a high molar extinction coefficient (ϵ=87250 ± 1630 M-1cm-1) and quantum yield (φ) of 0.589 ± 0.070 in water. Reported here is also the application of ROSA towards synthesis of a ROSA-PEG-GRGDS-NH2 fluorescent probe suitable for live cell imaging of αvβ3 integrins for in vitro assays. Objective: The main objective of this study is to efficiently prepare rhodamine B derivative, devoid of spirolactone formation that would be suitable for bioconjugation and subsequent bioimaging. Methods: Rhodamine B was transformed into rhodamine B succinimide ester (RhoB-OSu) using N-hydroxysuccinimide. RhoB-OSu was further coupled to sarcosine to obtain rhodamine Bsarcosine dye (ROSA) in good yield. The ROSA dye was then coupled to a αvβ3 integrin binding sequence using standard solid-phase conditions. Resulting ROSA-PEG-GRGDS-NH2 probe was used to image integrins on cancer cells. Results: The rhodamine B-sarcosine dye (ROSA) was obtained in multigram scale in good total yield of 47%. Unlike rhodamine B, the ROSA dye does not undergo pH-dependent spirolactone/spirolactam formation as compared with rhodamine B-glycine. It is also characterized by excellent quantum yield (φ) of 0.589 ± 0.070 in water and high molar extinction coefficient of 87250 ± 1630 M-1cm-1. ROSA coupling to the RGD-like peptide was proved to be efficient and straightforward. Imaging using standard filters on multimode plate reader and confocal microscope was performed. The αvβ3 integrins present on the surface of live WM-266-4 (melanoma) and MCF- 7 (breast cancer) cells were successfully imaged. Conclusion: We successfully derivatized rhodamine B to create an inexpensive, stable and convenient to use fluorescent probe. The obtained derivative has excellent photochemical properties and it is suitable for bioconjugation and many imaging applications.

scholarly journals N-[(1R)-1-(4-Chlorophenyl)ethyl]-Cyanamide

Molbank ◽  
10.3390/m1198 ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. M1198
Author(s):  
Rebeca González-Fernández ◽  
Pascale Crochet ◽  
Victorio Cadierno
Keyword(s):  
1H Nmr ◽  
Diethyl Ether ◽  
Title Compound ◽  
Cyanogen Bromide ◽  
Specific Rotation

The title compound was synthesized by electrophilic cyanation of commercially available (R)-4-chloro-α-methylbenzylamine with cyanogen bromide in diethyl ether, and isolated as a yellow oil in 84% yield. It was characterized by 1H and 13C{1H] NMR, IR, HRMS, and specific rotation measurements.

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