New Z-chalcones obtained from aloe-emodin: Synthesis, characterization and photophysical properties

2019 ◽  
Vol 43 (3-4) ◽  
pp. 101-106
Author(s):  
Nieves Canudas ◽  
Manuel Moreno ◽  
Sara Pekerar ◽  
Carlos Gámez ◽  
Estefania Sucre ◽  
...  
Keyword(s):  
Potassium Hydroxide ◽  
Room Temperature ◽  
Photophysical Properties ◽  
Emission Spectra ◽  
Nmr Studies ◽  
Extinction Coefficients ◽  
Chalcone Derivatives ◽  
Aloe Emodin ◽  
Aldehyde Derivative ◽  
Molar Extinction Coefficients

Three new Z-chalcone derivatives were synthesized under stereoselective conditions by condensation between an aldehyde derivative (prepared from aloe-emodin) and an acetophenone, using potassium hydroxide in dimethyl sulfoxide/H2O at room temperature. The Z configuration of the chalcone derivatives was established by nuclear magnetic resonance (NMR) studies. Photophysical properties related to the UV-Vis absorption/emission spectra and molar extinction coefficients (ε) in different solvents were determined.

Cyclometalated Ir(III) Complexes Containing Pyrazole/Pyrazine Carboxylate Ligands

2011 ◽  
Vol 64 (5) ◽  
pp. 561 ◽  
Author(s):  
Tanima Hajra ◽  
Jitendra K. Bera ◽  
Vadapalli Chandrasekhar
Keyword(s):  
Carboxylic Acid ◽  
Dicarboxylic Acid ◽  
Room Temperature ◽  
Photophysical Properties ◽  
Emission Spectra ◽  
Carboxylate Ligands ◽  
Ancillary Ligands

Two cyclometalated Ir(iii) complexes using 2-phenylpyridine (ppy-H) as the cyclometalating ligand, and pyrazole-3-carboxylic acid (prca-H) and pyrazine 3,5-dicarboxylic acid (pzdca-H2) as ancillary ligands; were synthesized from the chloro-bridged dimer precursor [{(ppy)2Ir}2(μ-Cl)2]. The title compounds [Ir(ppy)2(prca)] (1) and [{Ir(ppy)2}2(pzdca)] (2) are monomeric and dimeric neutral Ir(iii) complexes, respectively. Their electrochemical and photophysical properties were examined. They exhibit metal-based oxidations and ligand-based reductions. These complexes exhibit emission in the blue-green region with lifetimes in the micro-second range at room temperature. The nature of the emission spectra indicates differences in the origin of emission in these two compounds.

15N NMR studies provide insights into physico-chemical properties of room-temperature ionic liquids

2021 ◽  
Author(s):  
Christoph Wiedemann ◽  
David Fushman ◽  
Frank Bordusa
Keyword(s):  
Ionic Liquids ◽  
Room Temperature ◽  
Chemical Properties ◽  
Room Temperature Ionic Liquids ◽  
15N Nmr ◽  
Nmr Studies ◽  
Physico Chemical ◽  
Alternative Solvents

Ionic liquids (ILs) have gained a lot of attention as alternative solvents in many fields of science in the last two decades. It is known that the type of anion...

Photophysical properties of N719 and Z907 dyes, benchmark sensitizers for dye-sensitized solar cells, at room and low temperature

2021 ◽  
Vol 23 (10) ◽  
pp. 6182-6189
Author(s):  
Dariusz M. Niedzwiedzki
Keyword(s):  
Solar Cells ◽  
Low Temperature ◽  
Optical Spectroscopy ◽  
Room Temperature ◽  
Photophysical Properties ◽  
Dye Sensitized Solar Cells ◽  
Time Resolved ◽  
Dye Sensitized ◽  
Sensitized Solar Cells

Photophysical properties of N719 and Z907, benchmark Ru-dyes used as sensitizers in dye-sensitized solar cells, were studied by static and time-resolved optical spectroscopy at room temperature and 160 K.

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.

Preparation and Properties of La2O3-CaO-P2O5 Glasses Doped with Eu3+ Ions

2016 ◽  
Vol 675-676 ◽  
pp. 376-379 ◽  
Author(s):  
Narun Luewarasirikul ◽  
Piyachat Meejitpaisan ◽  
Jakrapong Kaewkhao
Keyword(s):  
Calcium Phosphate ◽  
Molar Volume ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Emission Spectra ◽  
Phosphate Glasses ◽  
Excitation Wavelength ◽  
Melt Quenching ◽  
Volume Measurements ◽  
Doped Glasses

Lanthanum calcium phosphate glasses doped with Eu3+ ions in compositions 20La2O3:10CaO:(70-x)P2O5:xEu2O3 (where x = 0.05, 0.10, 0.50 and 1.50 mol%) were prepared by melt-quenching technique. The density and molar volume measurements were carried out at room temperature. The absorption spectra were investigated in the UV-Vis-NIR region from 200 to 2500 nm. The emission spectra of Eu3+-doped glasses centered at 590 nm (5D0→7F1), 612 nm (5D0→7F2), 652 nm (5D0→7F3) and 699 nm (5D0→7F4) have been observed with 393 nm excitation wavelength.

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.

scholarly journals Absorption and Emission Spectra for C60 Anions

1994 ◽  
Vol 14 (1-3) ◽  
pp. 155-160 ◽  
Author(s):  
Tatsuhisa Kato
Keyword(s):  
Absorption Spectrum ◽  
Absorption Band ◽  
Theoretical Analysis ◽  
Room Temperature ◽  
Emission Spectra ◽  
Mirror Image ◽  
Ir Absorption ◽  
Near Ir ◽  
Laser Experiments ◽  
Ir Bands

Absorption spectra are detected for C60− and C602− produced electrolytically in solution at room temperature. Theoretical analysis of the spectrum of C60− by CNDO/S calculations gives an interpretation of the characteristic near-IR bands, the weak visible bands, and the strong bands in the UV region. The emission spectrum of C60− is a mirror image of the near-IR absorption band, and the detection of the emission reconfirms our original assignment of the absorption spectrum. The nature of the spectrum of C602− is characterized by a similar orbital picture to that of C60−. Further laser experiments of significance are proposed.

Sign in / Sign up

Export Citation Format

Share Document