Fluorescence quantum yields

The synthesis, photophysical and electrochemical properties of hexyl thiophene substituted thieno[b]-fused BODIPY structure are reported within this work. One such derivative, HTFBod, has been studied, which is one of the rare compounds that has a maximum absorbance wavelength greater than 750 nm among fused BODIPY compounds. In addition, it preserves its significant spectral properties such as high molar absorptivity and fluorescence quantum yield.

17p lyhuyenthu 31-01-2023 4 2   Download

The synthesis of a 4-(2,2-diphenylethoxy)phthalonitrile (1) and its organosoluble free base (2), zinc(II) (3), nickel(II) (4), and cobalt(II) (5) phthalocyanine derivatives is presented in this work. The novel complexes were characterized by elemental analyses and spectral data such as infrared, nuclear magnetic resonance, ultraviolet visible, and mass data. General tendencies were described for photophysics (fluorescence) and photochemistry (photodegradation and singlet oxygen quantum yields) of the free base and zinc(II) phthalocyanine derivatives in dimethylformamide.

11p langthannam 29-12-2021 8 0   Download

The synthesis of novel zinc, cobalt, indium, and metal-free phthalocyanines carrying four 3-(4-phenyloxy)coumarins in the periphery/nonperiphery were prepared by cyclotetramerization of 3-[4-(3,4-dicyanophenyloxy)phenyl]coumarin (2)/3-[4-(2,3- dicyanophenyloxy)phenyl]coumarin (3). The novel chromogenic compounds were characterized by elemental analysis, 1 H NMR, mass spectra, F-IR, and UV-vis spectral data. The effects of the coumarin units on the zinc, indium, and metal-free phthalocyanine complexes (2a/3a, 2c/3c, 2d/3d) were also investigated.

16p langthannam 29-12-2021 14 0   Download

The thermal stabilities of the phthalocyanine compounds were determined by thermogravimetric analysis. For metal-free (2) and zinc (3) phthalocyanines, photochemical (photodegradation and singlet oxygen quantum yields) and photophysical (fluorescence quantum yields and fluorescence lifetimes) properties were analyzed in dimethylsulfoxide (DMSO). The cobalt (4) and copper (5) phthalocyanines were not evaluated for this purpose because of their paramagnetic behavior. The metal-free (2) and zinc (3) phthalocyanines’ fluorescence quenching behaviors were also investigated.

17p langthannam 29-12-2021 11 0   Download

This study aimed to synthesize an oligo(azomethine-ether) with benzothiazole moiety in organic medium by means of chemical oxidative polycondensation (OP). Optical properties were examined by photoluminescence (PL) and UV-Vis measurements both in solutions and solid film involved a poly (methyl methacrylate) (PMMA) matrix. Oligomer film in the PMMA matrix emitted a fine green light with a fluorescence quantum yield (QY) of 3.30%. Spectral and thermal observations showed a high rate of C–O–C coupling (cross-linking) for the oligomer.

18p langthannam 29-12-2021 7 1   Download

Two fluorescent tetra- and mono-dansylated resorcinarene cavitands were prepared and fully characterized. The X-ray structure of mono-dansylated resorcinarene cavitand was obtained. Their intrinsic absorption and fluorescence properties were studied. These properties were strongly sensitive to the presence of perchloric acid, as evidenced by the appearance of isobestic points upon protonation of the dansyl dimethylamino functions.

10p langthannam 29-12-2021 8 0   Download

Pyrene dye has many superior characteristics for oxygen sensing studies such as long fluorescence lifetime, high quantum yield, and good sensitivity. It is preferred in some cases over ruthenium dyes for its more lipophilic character and higher sensitivity. However, easy photodegradation of pyrene is a challenging problem. In this study, pyrene dye was for the first time immobilized in an ethyl cellulose matrix and used for oxygen sensing in the form of thin films and electrospun sensing slides.

17p langthannam 29-12-2021 11 0   Download

Three new asymmetrical photochromic diarylethenes containing a variable heteroaryl ring and a quinoline unit were synthesized and their structures were determined by single-crystal X-ray diffraction analysis. Their properties, including photochromism, acidichromism, and fluorescence, were investigated systematically. For these diarylethenes, the one with an indole moiety had the largest absorption maximum, cyclization quantum yield, photoconversion ratio, emission peak, and fluorescent modulation efficiency.

16p langthannam 29-12-2021 5 0   Download

The synthesis and characterization of novel tetraalkylthio (SC6H13 or SC12H25) substituted µ-oxo silicon(IV) phthalocyanines (3a and 3b) and their µ-oxo derivatives (4a and 4b) were described in this study. These silicon(IV) phthalocyanines were characterized using different spectroscopic techniques such as UV-Vis, 1H NMR, FTIR, and mass and elemental analysis, as well.

24p tudichquannguyet 29-11-2021 9 1   Download

Phenoxy- and naphthoxy-substituted bisphenol-bridged cyclic phosphazenes were synthesized in 2 steps and their thermal, photophysical, and electrochemical properties were investigated. The structures of the cyclic phosphazene compounds were determined by ESI-MS mass spectrometry and 1 H, 13 C, and 31P NMR spectroscopies. The photophysical studies of phenoxy- and naphthoxy-substituted bridged cyclophosphazenes were investigated by means of absorption and fluorescence spectroscopies in different solvents. Thermal and electrochemical properties of the target compounds were also studied.

25p tudichquannguyet 29-11-2021 7 2   Download

In this article, we have reviewed the recent progress made in this newest member of carbon nanomaterials, focusing on their synthetic strategies namely top-down and bottom-up methods. In addition, their properties including morphology and structure, compositions, optical properties (absorbance, photoluminescence properties, quantum yields and luminescence mechanisms) have been presented.

14p caygaocaolon11 18-04-2021 27 3   Download

A field study was conducted with an objective to assess diurnal variations in photosynthetic pigments and chlorophyll fluorescence parameters in two stay green wheat genotypes viz. DL 1266- 1 and Arina 166 to gain insight into photoprotective regulation mediated by photosynthetic pigments during grain filling under late sown heat stress condition. Heat stress was imposed by delaying sowing date i.e. 12th January. Diurnal alterations in temperature affected all the parameters associated with photosynthetic pigments and chlorophyll fluorescence.

7p nguathienthan3 27-02-2020 27 0   Download

Recently, carbon dots (CDs) have attracted great attention due to their superior properties, such as biocompatibility, fluorescence, high quantum yield, and uniform distribution. These characteristics make CDs interesting for bioimaging, therapeutic delivery, optogenetics, and theranostics. Photoluminescence (PL) properties enable CDs to act as imaging-trackable gene nanocarriers, while cationic CDs with high transfection efficiency have been applied for plasmid DNA and siRNA delivery.

13p caygaocaolon1 13-11-2019 7 0   Download

I started my first photobiological research project almost exactly 50 years ago, in the spring of 1957. My scientific interest ever since has been focused on photobiology in its many aspects. Because I have been employed as a botanist, my own research has dealt with the photobiology of plants, but throughout this time I have been interested in other aspects, such as vision, the photobiology of skin, and bioluminescence. A first edition of the present book was published in 2002, but this second edition is much expanded and completely updated.

695p banhkem0908 24-11-2012 73 13   Download