Fluorescence of Cyclic Adducts of Fullerene

1994 ◽  
Vol 359 ◽  
Author(s):  
Tsung-I Lin ◽  
Syh-Kun Lin ◽  
Lung-Lin Shiu ◽  
Kuo-Ming Chien ◽  
Tien-Yau Luh
Keyword(s):  
Spectral Properties ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Parent Compound ◽  
Molar Absorptivity ◽  
Absorption Bands ◽  
Polar Solvents ◽  
Peak Broadening ◽  
Stokes Shifts ◽  
Cyclic Adducts

ABSTRACTFive cyclic adducts C60C4H6, C60C5H6, C60NHCO2, C60NCO2Et, and C60CHCO2Et have been synthesized and their absorption and fluorescence spectral properties investigated and compared with those of the parent. Breaking the structural symmetry of C60 apparently resulted in enhancing the quantum yield two to three-folds in some adducts and thus made fluorescence much easier to be measured at room temperature. New absorption bands and altered fluorescence spectra were observed in the adducts. The Stokes' shifts of the adducts were small, about 4-5 nrm, compared to 68 nm for the parent compound. All the adducts exhibited a single fluorescence lifetime about the same as C60 (ca. 1.3 ns). Aliphatic solvents had little influence on the absorption or fluorescence spectral profile except on the molar absorptivity whereas aromatic and polar solvents strongly interacted with the adducts causing a peak broadening effect.

scholarly journals Studying the spectral properties of thin films of rhodamine (6G) dyes doped polymer (PMMA) dissolved in chloroform

2019 ◽  
Vol 12 (23) ◽  
pp. 59-64
Author(s):  
Ali H. Al-Hamdani
Keyword(s):  
Thin Films ◽  
Quantum Efficiency ◽  
Spectral Properties ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Rhodamine 6G ◽  
Composite Films ◽  
Peak Shift ◽  
Doped Polymer ◽  
Made In

              In the present work, poly methyl methacrylate (PMMA) doped with Rhodamine 6G was prepared. The spectral properties (absorption and fluorescence) of the films were studied at different concentrations (1x10-5, 2x10-5, 5x10-5, 7x10-5, and 1x10-4mol/l). The investigated samples were made in the form of thin films. This was achieved by dissolving a certain weight of PMMA in a fixed volume of chloroform, composite films was with thickness (25.8μm) at room temperature. The achieved results were pointed out that absorption and fluorescence spectra have taken a wide spectral rang so when increased the concentration each peak shift toward along wavelength. The quantum efficiency of the films were calculated as follows (98%,89%,84%,83% and 76%) for the above concentrations respectively. It has been noticed that the quantum efficiency decreases as the concentrations increases.

Ultraviolet Absorption and Fluorescence Studies of 1-Methyl-2(1H)-Pyridinimine and Derivative in Polar and Non-Polar Solvents

2000 ◽  
Vol 53 (12) ◽  
pp. 951 ◽  
Author(s):  
Hassimi Traore ◽  
Michael Saunders ◽  
Scott Blasiman
Keyword(s):  
Fluorescence Spectra ◽  
Room Temperature ◽  
Potential Surface ◽  
Polar Solvents ◽  
Potential Surfaces ◽  
Fluorescence Studies ◽  
Pyridinium Cation ◽  
Vibronic Interactions ◽  
State Potential ◽  
Solute Interactions

The ultraviolet (u.v.) and fluorescence spectra and relative fluorescence intensities of 1-methyl-2(1H)-pyridinimine (1-MIP) and 1,2-dimethylpyridinimine (2-MIP) were measured in several solvents at room temperature. The solvents’ effect on the absorption and fluorescence spectra of MIP indicates that the ππ* transition shifts to higher energies (shorter wavelengths) are due to solvents’ interactions and the formation of the pyridinium cation. One major difference in the u.v. and fluorescence spectra is the small relative intensity in non-polar solvents. This was attributed to the proximity effect of ππ* and nπ* states which can lead to vibronic interactions, and to distortions of the excited-state potential surfaces. In polar solvents, however, these two states are shifted in energy due to solvent–solute interactions, which decrease the energy of the potential surface.

The specific and nonspecific solvatochromic behavior of Sudan dyes in different solvents

2015 ◽  
Vol 93 (6) ◽  
pp. 639-647 ◽  
Author(s):  
M.S. Zakerhamidi ◽  
S.M. Seyed Ahmadian ◽  
R. Kian
Keyword(s):  
Fluorescence Spectra ◽  
Room Temperature ◽  
Molecular Configuration ◽  
Sudan Dyes ◽  
Polar Solvents ◽  
Sudan Black B ◽  
Sudan Iv ◽  
Sudan Iii ◽  
Linear Solvation Energy ◽  
Solute Interactions

Absorption and fluorescence spectra of some Sudan dyes (Sudan III, Sudan IV, and Sudan Black B) were recorded in various solvents in the range of 300–800 nm at room temperature. The solvatochromic behavior of these substances and their solvent–solute interactions were analyzed by means of the linear solvation energy relationship concept suggested by Kamlet and Taft. The obtained results express the effect of solvation on the tautomerism and molecular configuration (geometry) of Sudan dyes in solvent media. Furthermore, analysis of solvent–solute interactions suggests different forms of resonance structures of Sudan dyes in polar and low-polar solvents.

Synthesis structural and spectroscopic properties of quinoxaline-bridged bisBODIPYs

2018 ◽  
Vol 22 (09n10) ◽  
pp. 899-907
Author(s):  
Changjiang Yu ◽  
Tingting Li ◽  
Qinghua Wu ◽  
Wenbo Hu ◽  
Erhong Hao ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Spectroscopic Properties ◽  
Knoevenagel Reaction ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
Polar Solvents ◽  
Broad Absorption ◽  
X Ray ◽  
Stokes Shifts

Two novel quinoxaline-bridged bisBODIPYs have been synthesized by the condensation of 2,3-bis(5-formylpyrrol-2-yl)quinoxaline with 3-ethyl-2,4-dimethylpyrrole followed by a modification using a Knoevenagel reaction. They were well characterized by X-ray diffraction, NMR, HRMS UV-vis and fluorescence spectroscopy. These two quinoxaline-bridged bisBODIPYs have unusual broad absorption bands, which are different from those of typical BODIPYs They exhibit broad red-shifted emission bands centered at around 610 nm and 730 nm respectively with larger Stokes shifts at the range of 1421–2136 cm[Formula: see text] Both bisBODIPYs show different extent solvent-dependent fluorescence and exhibit fluorescence quenching in polar solvents due to the existence of possible intramolecular charge transfer.

Fluorescence Quantum Yields of 2-Substituted 3-Methylquinoxalines in Liquid Solutions at Room Temperature

1991 ◽  
Vol 46 (8) ◽  
pp. 700-702
Author(s):  
A. Kawski ◽  
K. Nowaczyk ◽  
B. Kuklinski
Keyword(s):  
Quantum Yield ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Atomic Weight ◽  
Modulation Method ◽  
Quantum Yields ◽  
Strong Decrease ◽  
Polar Solvents ◽  
Fluorescence Quantum Yields ◽  
Liquid Solutions

AbstractA sensitivity modulation method was employed to measure the fluorescence spectra and quantum yields of weakly fluorescent 2-substituted (NH2, O, OCH3, CI, Br) 3-methylquinoxalines in n-hexane and methanol at room temperature. A strong decrease in the quantum yield with increasing atomic weight of the substituents was observed in n-hexane. In polar solvents, the CI substituent is the strongest quencher although its atomic weight is 2.254 times smaller than that of Br

Infrared spectra of N-acetyl-L-α-amino-acid N'-methylamides with aliphatic side chains in non-polar solvents

1981 ◽  
Vol 46 (3) ◽  
pp. 772-780 ◽  
Author(s):  
Jorga Smolíková ◽  
Jan Pospíšek ◽  
Karel Bláha
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Side Chains ◽  
Polar Solvents

Infrared spectra of the L-alanine (I), L-leucine (II), L-valine (III) and L-tert-leucine (IV) N-acetyl N'-methylamides were measured. Amides I-IV are not self associated in tetrachlormethane in the concentration 2 . 10-5 mol l-1 at room temperature and in tetrachloroethylene in the concentration 1.5 . 10-4 mol l-1 at temperatures above 65° C. True conformational changes are observable only with the least flexible amide IV which exists at room temperature in a C5 conformation. This conformational type is also highly populated in the valine derivative III, but is less important in the alanine and leucine derivatives I and II in which the intramolecularly bonded C7 and the distorted hydrogen-nonbonded conformations contribute seriously.

A phthalocyanine-based fluorescent sensor for Zn2+ ion

2013 ◽  
Vol 17 (01n02) ◽  
pp. 99-103 ◽  
Author(s):  
Hui He ◽  
Jian-Yong Liu ◽  
Dennis K.P. Ng
Keyword(s):  
Metal Ions ◽  
Spectral Properties ◽  
Fluorescence Spectra ◽  
Near Infrared ◽  
Fluorescent Sensor ◽  
High Sensitivity ◽  
Absorption And Fluorescence Spectra

This paper describes the preparation and spectral properties of a near-infrared fluorophore in which two bis(2-picolyl)amino moieties are axially linked to a silicon(IV) phthalocyanine core. The effects of various metal ions on its absorption and fluorescence spectra have been examined. The results indicate that this compound shows a high sensitivity and moderate selectivity toward Zn2+ ion.

Thermal Breakdown Kinetics of 1-Ethyl-3-Methylimidazolium Ethylsulfate Measured Using Quantitative Infrared Spectroscopy

2017 ◽  
Vol 71 (12) ◽  
pp. 2626-2631 ◽  
Author(s):  
Jeffrey L. Wheeler ◽  
McKinley Pugh ◽  
S. Jake Atkins ◽  
Jason M. Porter
Keyword(s):  
Thermal Stability ◽  
Room Temperature ◽  
Computational Models ◽  
Elevated Temperatures ◽  
Molar Absorptivity ◽  
Ir Absorption ◽  
Optical Cell ◽  
Multiple Samples ◽  
Kinetics Of ◽  
Thermal Stability Of

In this work, the thermal stability of the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO4]) is investigated using infrared (IR) spectroscopy. Quantitative IR absorption spectral data are measured for heated [EMIM][EtSO4]. Spectra have been collected between 25 ℃ and 100 ℃ using a heated optical cell. Multiple samples and cell pathlengths are used to determine quantitative values for the molar absorptivity of [EMIM][EtSO4]. These results are compared to previous computational models of the ion pair. These quantitative spectra are used to measure the rate of thermal decomposition of [EMIM][EtSO4] at elevated temperatures. The spectroscopic measurements of the rate of decomposition show that thermogravimetric methods overestimate the thermal stability of [EMIM][EtSO4].

Local Structure and Er3+ Emission from Pseudo-Amorphous GaN:Er Thin Films

1998 ◽  
Vol 536 ◽  
Author(s):  
S. B. Aldabergenova ◽  
M. Albrecht ◽  
A. A. Andreev ◽  
C. Inglefield ◽  
J. Viner ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Amorphous Matrix ◽  
Broad Band ◽  
Resonant Absorption ◽  
Absorption Bands ◽  
Host Matrix ◽  
Transmission Electron ◽  
Infra Red ◽  
Band Edge Luminescence

AbstractWe report on strong Er3+ luminescence in the visible and infra-red regions at room temperature in amorphous GaN:Er thin films prepared by DC magnetron co-sputtering. The intensity of the Er3+ luminescence at 1.535 μm corresponding to 4I13/2 → 4I15/2 transitions is greatly enhanced after annealing at 750°C. In this material GaN crystallites have formed and embedded in the continuous amorphous matrix. The crystallites are 4 to 7 nm in diameter as analyzed by high resolution transmission electron microscopy. The absorption edge, extending three orders of magnitude in absorption coefficient in the spectral range from 0.5 to 3.5 eV, is superimposed on resonant absorption bands of Er3+ ions.The total photoluminescence spectrum consists of welldefined Er3+ luminescence peaks imposed on a broad band edge luminescence from the amorphous GaN host matrix.

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