Influence of molecular weight on the spectroscopic properties of a series of well-defined poly(3-hexylthiophene) polymers

2011 ◽  
Vol 89 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Qiliang Peng ◽  
Ian W. Wyman ◽  
Dehui Han ◽  
Guojun Liu
Keyword(s):  
Molecular Weight ◽  
Refractive Index ◽  
Fluorescence Spectroscopy ◽  
Spectroscopic Properties ◽  
Extinction Coefficients ◽  
Maximum Absorbance ◽  
Molar Extinction Coefficients

A series of five poly(3-hexylthiophene) (P3HT) polymers were prepared, and their spectroscopic properties were studied. These polymers were well defined, with polydispersity indices no larger than 1.20 and regioregularities that were above 90% for each member of the series. The P3HT polymers were characterized using UV–vis and fluorescence spectroscopy, and their specific refractive index increments were measured in tetrahydrofuran. The influence of the molecular weight of these polymers on their maximum absorbance and emission wavelengths, molar extinction coefficients, and refractive index increments was studied.

scholarly journals Using photocaging for fast time-resolved structural biology studies

2021 ◽  
Vol 77 (10) ◽  
pp. 1218-1232
Author(s):  
Diana C. F. Monteiro ◽  
Emmanuel Amoah ◽  
Cromarte Rogers ◽  
Arwen R. Pearson
Keyword(s):  
Structural Biology ◽  
Spectroscopic Properties ◽  
Decay Rates ◽  
Quantum Yields ◽  
Fast Time ◽  
Time Resolved ◽  
Extinction Coefficients ◽  
Reaction Initiation ◽  
Selection Of ◽  
Molar Extinction Coefficients

Careful selection of photocaging approaches is critical to achieve fast and well synchronized reaction initiation and perform successful time-resolved structural biology experiments. This review summarizes the best characterized and most relevant photocaging groups previously described in the literature. It also provides a walkthrough of the essential factors to consider in designing a suitable photocaged molecule to address specific biological questions, focusing on photocaging groups with well characterized spectroscopic properties. The relationships between decay rates (k in s−1), quantum yields (φ) and molar extinction coefficients (ɛmax in M −1 cm−1) are highlighted for different groups. The effects of the nature of the photocaged group on these properties is also discussed. Four main photocaging scaffolds are presented in detail, o-nitrobenzyls, p-hydroxyphenyls, coumarinyls and nitrodibenzofuranyls, along with three examples of the use of this technology. Furthermore, a subset of specialty photocages are highlighted: photoacids, molecular photoswitches and metal-containing photocages. These extend the range of photocaging approaches by, for example, controlling pH or generating conformationally locked molecules.

scholarly journals Antimicrobial Activity of Cationic Poly(3-hexylthiophene) Nanoparticles Coupled with Dual Fluorescent and Electrochemical Sensing: Theragnostic Prospect

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1715
Author(s):  
Nada Elgiddawy ◽  
Shiwei Ren ◽  
Wadih Ghattas ◽  
Waleed M. A. El Rouby ◽  
Ahmed O. El-Gendy ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Fluorescence Spectroscopy ◽  
Bacterial Infections ◽  
Electrochemical Impedance ◽  
Spectroscopic Properties ◽  
Electrochemical Sensing ◽  
E Coli ◽  
Normal Human ◽  
Dual Detection ◽  
Bacteria And Fungi

Designing therapeutic and sensor materials to diagnose and eliminate bacterial infections remains a significant challenge for active theragnostic nanoprobes. In the present work, fluorescent/electroactive poly(3-hexylthiophene) P3HT nanoparticles (NPs) stabilized with quaternary ammonium salts using cetyltrimethylammonium bromide (CTAB), (CTAB-P3HT NPs) were prepared using a simple mini-emulsion method. The morphology, spectroscopic properties and electronic properties of CTAB-P3HT NPs were characterized by DLS, zeta potential, SEM, TEM, UV-vis spectrophotometry, fluorescence spectroscopy and electrochemical impedance spectroscopy (EIS). In an aqueous solution, CTAB-P3HT NPs were revealed to be uniformly sized, highly fluorescent and present a highly positively charged NP surface with good electroactivity. Dual detection was demonstrated as the binding of the bacteria to NPs could be observed by fluorescence quenching as well as by the changes in EIS. Binding of E. coli to CTAB-P3HT NPs was demonstrated and LODs of 5 CFU/mL and 250 CFU/mL were obtained by relying on the fluorescence spectroscopy and EIS, respectively. The antimicrobial activity of CTAB-P3HT NPs on bacteria and fungi was also studied under dark and nutritive conditions. An MIC and an MBC of 2.5 µg/mL were obtained with E. coli and with S. aureus, and of 0.312 µg/mL with C. albicans. Additionally a good biocompatibility toward normal human cells (WI38) was observed, which opens the way to their possible use as a therapeutic agent.

ASSOCIATION OF CERIC IONS WITH SULPHATE (A SPECTRAL STUDY)

1951 ◽  
Vol 29 (10) ◽  
pp. 828-837 ◽  
Author(s):  
T. J. Hardwick ◽  
E. Robertson
Keyword(s):  
Spectral Study ◽  
Association Constants ◽  
Extinction Coefficients ◽  
Ceric Ion ◽  
Molar Extinction Coefficients

Ceric ion has been shown to associate with sulphate ion to form successively Ce(SO4++, Ce(SO4)2, and Ce(SO4)3−. The association constants relating these species have been determined at 25 °C. The molar extinction coefficients of each associated complex have been found between 395 and 430 mμ. Migration experiments bear out the results qualitatively.

Synthesis and characterization of meso-to-meso directly linked porphyrin-diazaporphyrin triads

2018 ◽  
Vol 22 (09n10) ◽  
pp. 814-820
Author(s):  
Yingying Jia ◽  
Ling Xu ◽  
Bangshao Yin ◽  
Mingbo Zhou ◽  
Jianxin Song
Keyword(s):  
Nickel Complex ◽  
High Resolution Mass Spectrometry ◽  
Dihedral Angles ◽  
X Ray Diffraction ◽  
Extinction Coefficients ◽  
X Ray ◽  
H Nmr ◽  
First Time ◽  
Molar Extinction Coefficients

Beginning with 5,10,15-triarylporphyrin-nickel complex, five meso-to-meso directly linked porphyrin-diazaporphyrin triads were successfully prepared for the first time through a series of reactions including formylation via Vilsmeier–Haack reaction, condensation with pyrrole, bromination with [Formula: see text]-Bromosuccinimide (NBS), oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), metal-templated cyclization of dibromodipyrrin-metal complexes with NaN[Formula: see text] and demetalization. All these triads were comprehensively characterized by [Formula: see text]H NMR, high-resolution mass spectrometry and UV-vis absorption. In addition, the structure of compound 6Ni was unambiguously determined by X-ray diffraction analysis, which showed that the two dihedral angles are both 86.65 (4)[Formula: see text] between each mean plane of porphyrin and that of central diazaporphyrin The UV-vis absorption spectra disclosed that the longest wavelengths of Soret bands and Q bands for these triads were observed at 429 and 642 nm, respectively. In contrast to diazaporphyrin-porphyrin dyads, diazaporphyrin dimers and diazaporphyrin monomers reported previously the molar extinction coefficients, particularly for triad 8Ni are much higher.

scholarly journals Quantification of acidic sites of nanoscopic hydroxylated magnesium fluorides by FTIR and 15N MAS NMR spectroscopy

RSC Advances ◽  
2015 ◽  
Vol 5 (109) ◽  
pp. 89659-89668 ◽  
Author(s):  
Felix Hemmann ◽  
Iker Agirrezabal-Telleria ◽  
Christian Jaeger ◽  
Erhard Kemnitz
Keyword(s):  
Nmr Spectroscopy ◽  
Mas Nmr ◽  
New Method ◽  
Extinction Coefficients ◽  
Surface Sites ◽  
Acidic Sites ◽  
Molar Extinction Coefficients

A new method is described for the calculation of molar extinction coefficients for quantitative FTIR measurements of acidic surface sites.

Aromatic Ring Index (ARI): A Characterization Factor for Nonpolar Hydrocarbons from Molecular Weight and Refractive Index

2021 ◽  
Vol 35 (2) ◽  
pp. 1113-1119
Author(s):  
Mohammed I. L. Abutaqiya ◽  
Ali A. AlHammadi ◽  
Caleb J. Sisco ◽  
Francisco M. Vargas
Keyword(s):  
Molecular Weight ◽  
Refractive Index ◽  
Aromatic Ring ◽  
Characterization Factor

scholarly journals The Polymerization of MMA and ST to Prepare Material with Gradient Refractive Index in Electric Field

2015 ◽  
Vol 2015 ◽  
pp. 1-6
Author(s):  
Yao Huang ◽  
Daming Wu ◽  
Dongyun Ren ◽  
Qingyun Meng ◽  
Xiaojun Di
Keyword(s):  
Molecular Weight ◽  
Refractive Index ◽  
Electric Field ◽  
Cylindrical Sample ◽  
Electrical Field ◽  
Molecular Weights ◽  
The Matrix ◽  
Gradient Refractive Index ◽  
Scattering Material ◽  
Different Parts

Light scattering material with gradient refractive index was prepared under the electrical field by taking methyl methacrylate (MMA) monomer as the matrix with the addition of a little preheated styrene (ST) and peroxidation benzoin formyl (BPO). The material obtained under electrical field presented different transmittance and molecular weight at different parts of the cylindrical sample along the axis of the direction of electric field which led to the layering phenomenon and gradient refractive index. The disparity of molecular weight between different layers can be as much as 230 thousand. There were several peaks in the figure of GPC test of the sample under electric field. This proved that there were polymers with different molecular weights in the sample. Therefore, it can be concluded that electrical field has a significant effect on polymerization.

EXPERIMENTAL STUDIES OF SOLUTION PROCESSES: VI. EFFECT OF SOLVENT ON INFRARED ABSORPTION SPECTRA

1960 ◽  
Vol 38 (10) ◽  
pp. 1921-1926 ◽  
Author(s):  
P. A. D. De Maine ◽  
L. H. Daly ◽  
M. M. De Maine
Keyword(s):  
Infrared Absorption ◽  
Experimental Studies ◽  
Absorption Data ◽  
Frequency Shifts ◽  
Extinction Coefficients ◽  
Effect Of Solvent ◽  
Solution Processes ◽  
Pure Substances ◽  
Infrared Absorption Spectra ◽  
Molar Extinction Coefficients

Here are reported infrared absorption data between 4000 cm−1 and 700 cm−1 near 19 °C for methanol, n-propanol, isopropanol, cyclohexanol, benzyl alcohol, diethyl ether, anisole, 1,4-dioxane, diisopropyl ether, nitromethane, acetone, p-xylene, benzene, and hexane as pure substances and in carbon tetrachloride solution. Band frequencies accurate to within 1 cm−1 are reported. Except for the 3340 cm−1 band in dilute MeOH solutions no frequency shifts were observed even with gross changes of the electrical properties of the solutions. Molar extinction coefficients at absorption maxima are discussed briefly.

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