scholarly journals Investigation and detection of cyanobacterial Cr-phycoerythrin by laser based techniques

2014 ◽  
Vol 79 (2) ◽  
pp. 185-198 ◽  
Author(s):  
Bratislav Marinkovic ◽  
Ambra Delneri ◽  
Maja Rabasovic ◽  
Mira Terzic ◽  
Mladen Franko ◽  
...  
Keyword(s):  
Thermal Lens ◽  
High Sensitivity ◽  
Injection System ◽  
Quantum Yields ◽  
Excitation Wavelength ◽  
Lower Sensitivity ◽  
Time Resolved ◽  
Technical Parameters ◽  
Fluorescence Quantum Yields ◽  
High Fluorescence

The application of a high-sensitivity method of time resolved laser induced fluorescence (TR-LIF) and Flow-injection system by thermal lens spectrometry (FIA-TLS) for the analysis of Cr-Phycoerythrin (Cr-PE) isolated from a proprietary cyanobacterium is presented. In the excitation wavelength range (340-470 nm) fluorescent spectra exhibit a pronounced maximum at 575 nm. Another maximum, at about 600 nm can be also observed. The obtained results are used to verify the technical parameters of the used thermal lens technique, which is complementary to spectrofluorimetry and subject to lower sensitivity in case of high fluorescence quantum yields and photolability of measured compounds.

Regioselective Oxidative Cross-Coupling Reaction: Synthesis of Imidazo[1,2-a]pyridine Fluorophores

Synthesis ◽  
2021 ◽  
Author(s):  
Xianglong Chu ◽  
Yadi Niu ◽  
Chen Ma ◽  
Xiaodong Wang ◽  
Yunliang Lin ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
Cross Coupling Reaction ◽  
Color Tunable ◽  
Palladium Catalyzed ◽  
Structure Relationship ◽  
High Fluorescence

AbstractA rapid access to a series of N-heteroarene fluorophores has been developed on the basis of the palladium-catalyzed direct oxidative C–H/C–H coupling of imidazo[1,2-a]pyridines with thiophenes/furans. The photophysical properties–structure relationship was systematically investigated. The resulting N-heteroarene fluorophores present color-tunable emissions (λem: 431–507 nm in CH2Cl2) and high fluorescence quantum yields (up to 91% in CH2Cl2).

scholarly journals Photoluminescence in m-carborane–anthracene triads: a combined experimental and computational study

2018 ◽  
Vol 6 (42) ◽  
pp. 11336-11347 ◽  
Author(s):  
Mahdi Chaari ◽  
Zsolt Kelemen ◽  
José Giner Planas ◽  
Francesc Teixidor ◽  
Duane Choquesillo-Lazarte ◽  
...  
Keyword(s):  
Computational Study ◽  
Fluorescence Emission ◽  
Fluorescence Properties ◽  
Quantum Yields ◽  
Aggregate State ◽  
Fluorescence Quantum Yields ◽  
High Fluorescence

m-Carborane has demonstrated to be a perfect platform to boost the fluorescence properties of anthracene, giving rise to high fluorescence quantum yields in solution and also retaining fluorescence emission in the aggregate state.

Alkynylpyrenes as Improved Pyrene-Based Biomolecular Probes with the Advantages of High Fluorescence Quantum Yields and Long Absorption/Emission Wavelengths

2006 ◽  
Vol 12 (3) ◽  
pp. 824-831 ◽  
Author(s):  
Hajime Maeda ◽  
Tomohiro Maeda ◽  
Kazuhiko Mizuno ◽  
Kazuhisa Fujimoto ◽  
Hisao Shimizu ◽  
...  
Keyword(s):  
Quantum Yields ◽  
Fluorescence Quantum Yields ◽  
High Fluorescence

Understanding the Photoluminescence Mechanism of Carbon Dots

MRS Advances ◽  
2017 ◽  
Vol 2 (51) ◽  
pp. 2927-2934 ◽  
Author(s):  
Zhoufeng Jiang ◽  
Marta J. Krysmann ◽  
Antonios Kelarakis ◽  
Petr Koutnik ◽  
Pavel Anzenbacher ◽  
...  
Keyword(s):  
Carbon Dots ◽  
Quantum Yields ◽  
Excitation Wavelength ◽  
Time Resolved ◽  
Light Emitting ◽  
Dependent Component ◽  
Different Types ◽  
Photoluminescence Mechanism ◽  
Time Resolved Photoluminescence ◽  
Absolute Quantum

ABSTRACTThe carbon dots were investigated to reveal their light-emitting mechanism. The fluorescence spectra of carbon dots show typically two different types of photoluminescence: the excitation-independent component in the short wavelength, and the excitation-dependent component in the longer wavelength. The UV-Vis spectrum of carbon dots shows the absorption maximum of 340 nm which should be accredited to the n-π* transition of the carbonyl group in carbon dots. Absolute quantum yields of carbon dots dispersed in Polyvinyl alcohol is around 15% when the excitation wavelength is less than 425 nm, but decreases continuously when the excitation wavelength increases. The decay lifetimes of the carbon dots also show an abrupt change at excitation wavelength 425 nm. Time resolved photoluminescence was implemented from 31K to 291K to study the photoluminescence decay dynamics of carbon dots, resulting in the continuously decreasing of the lifetime as the temperature increases.

The Synthesis, Characterisation, Photophysical and Thermal Properties, and Photovoltaic Performance of 7-Coumarinoxy-4-Methyltetrasubstituted Metallophthalocyanines

2015 ◽  
Vol 68 (7) ◽  
pp. 1025 ◽  
Author(s):  
Jun-Jie Guo ◽  
Shi-Rong Wang ◽  
Xiang-Gao Li ◽  
Fei Zhang ◽  
Yin Xiao ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Transition Metal Complexes ◽  
Photovoltaic Performance ◽  
Quantum Yields ◽  
Stability Studies ◽  
Time Resolved ◽  
Extinction Coefficients ◽  
Fluorescence Quantum Yields ◽  
Photoluminescence Decay ◽  
Molar Extinction Coefficients

The synthesis, characterisation, photophysical and thermal properties of 2(3),9(10),16(17),23(24)-tetrakis(7-coumarinoxy-4-methyl)-phthalocyaninatozinc(ii) (ZnPc-Coumarin) and 2(3),9(10),16(17),23(24)-tetrakis(7-coumarinoxy-4-methyl)-phthalocyaninatocobalt(ii) (CoPc-Coumarin) are reported. The ground state absorbance of ZnPc-Coumarin shows molar extinction coefficients as high as 1.80 × 105 dm3 mol–1 cm–1. The fluorescence spectrum and fluorescence quantum yields of compounds ZnPc-Coumarin and CoPc-Coumarin are also investigated. The photoluminescence decay of the two transition-metal complexes in DMF solution, in poly(methyl methacrylate) (PMMA), and on TiO2 films has been studied with time-resolved emission. This study shows that the electron transfer from the dye to TiO2 is through space. The thermal stability studies indicate that both of the two complexes are stable up to 390°C. The ZnPc-Coumarin achieved a higher overall conversion efficiency than the reported SnPcCl2-Coumarin, InPcCl-Coumarin, and RuPcCl-Coumarin because of its slower charge recombination rate and faster electron injection from the dye to the conduction band of the conducting glass.

SYNTHESIS, FLUORESCENCE AND ELECTROCHEMICAL PROPERTIES OF SYMMETRICAL CHROMOPHORES WITH ELECTRON ACCEPTING OXADIAZOLE

2008 ◽  
Vol 17 (04) ◽  
pp. 473-485 ◽  
Author(s):  
XIAOQIN ZHU ◽  
YING QIAN ◽  
WEI HUANG ◽  
CHANGGUI LU ◽  
YIPING CUI
Keyword(s):  
Single Photon ◽  
Quantum Yields ◽  
Compound I ◽  
Central Wavelength ◽  
Good Thermal Stability ◽  
Fluorescence Quantum Yields ◽  
Two Photon ◽  
Homo And Lumo ◽  
High Fluorescence ◽  
Compound Ii

Two symmetrical TPA chromophores containing 1,3,4-oxadiazole group were designed and synthesized through the Wittig–Horner reaction. All compounds were characterized by NMR, IR, UV and melting point. Chromophore I and II showed good thermal stability and did lose less than 5% weight on heating to about 300°C. The electrochemical property was explored by cyclic voltammetry. The HOMO and LUMO energy of compound I were estimated to be -3.65 eV and -1.09 eV. That of compound II were -3.69 eV and -1.10 eV. Both chromophores exhibited a positive solvatochromic behavior. In CH2Cl2 , the maximum peaks of single-photon-excited fluorescence (SPEF) were at 512 nm for compound I and at 495 nm for compound II with high fluorescence quantum yields 0.73 and 0.70, respectively. The two-photon-excited fluorescence (TPEF) had also been investigated. Pumped by femtosecond laser at 800 nm, strong up-conversion emissions with the central wavelength were at 532 nm for compound I and 550 nm for compound II in the solution of CH2Cl2 .

High-Quality Water-Soluble Core/Shell/Shell CdSe/CdS/ZnS Quantum Dots Balanced by Ionic and Nonionic Hydrophilic Capping Ligands

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650073 ◽  
Author(s):  
Lu Liu ◽  
Hu Xu ◽  
Bing Shen ◽  
Xinhua Zhong
Keyword(s):  
Quantum Dots ◽  
Colloidal Stability ◽  
Water Soluble ◽  
Quantum Yields ◽  
Surface Charges ◽  
Fluorescence Quantum Yields ◽  
Carboxylic Groups ◽  
Potential Applications ◽  
High Fluorescence ◽  
Capping Ligands

Pentaerythritol tetrakis 3-mercaptopropionate (PTMP) grafted poly(acryl acid) (PAA) ionic hydrophilic oligomer PAA-PTMP (PP) and dihydrolipoic acid (DHLA) grafted methoxypoly(ethylene glycol) (mPEG) nonionic hydrophilic oligomer mPEG-DHLA (PD) have been designed, synthesized and used as co-capping ligands in water-solubilization of hydrophobic quantum dots (QDs) via ligand exchange. The obtained oligomers with multi-thiol groups could bind strongly to the surface atoms of QDs. Meanwhile, the carboxyl groups (from PP) and mPEG segment (from PD) can render QDs water-soluble, and the free carboxylic groups can possibly be used for the further bioconjugation. The resulting water-soluble QDs have been characterized by ultraviolet-visible (UV-Vis), fluorescence, Fourier transform infrared (FTIR) spectroscopy as well as transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The water-soluble QDs have relatively small hydrodynamic size (10[Formula: see text]12 nm), and importantly, retain high fluorescence quantum yields (up to 45%) compared with that of the originally hydrophobic QDs (49%). In addition, they have tunable surface charges and show excellent colloidal stability over a relatively broad pH range ([Formula: see text]), in high salt concentration, and even after thermal treatment at 100[Formula: see text]C. These results indicate that the water-soluble QDs coated by PP and PD oligomers have potential applications in cellular imaging and biosensor.

scholarly journals Towards Mycobacterium tuberculosis detection at the point-of-care: a brighter solvatochromic probe permits the detection of mycobacteria within minutes

2020 ◽  
Author(s):  
Mireille Kamariza ◽  
Samantha G. L. Keyser ◽  
Ashley Utz ◽  
Benjamin D. Knapp ◽  
Green Ahn ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Fluorescence Intensity ◽  
Point Of Care ◽  
Fold Increase ◽  
Diagnostic Methods ◽  
Quantum Yields ◽  
Low Resource Settings ◽  
Fluorescence Quantum Yields ◽  
High Fluorescence ◽  
Solvatochromic Dye

ABSTRACTThere is an urgent need for point-of-care tuberculosis (TB) diagnostic methods that are fast, inexpensive, and operationally simple. Here, we report on a bright solvatochromic dye trehalose conjugate that specifically detects Mycobacterium tuberculosis (Mtb) in minutes. 3-hydroxychromone (3HC) dyes, known to yield high fluorescence quantum yields, exhibit shifts in fluorescence intensity in response to changes in environmental polarity. We synthesized two analogs of 3HC-trehalose conjugates (3HC-2-Tre and 3HC-3-Tre) and determined that 3HC-3-Tre has exceptionally favorable properties for Mtb detection. 3HC-3-Tre-labeled mycobacterial cells displayed a 10-fold increase in fluorescence intensity compared to our previously reports on the dye 4,4-N,N-dimethylaminonapthalimide (DMN-Tre). Excitingly, we detected fluorescent Mtb cells within 10 minutes of probe treatment. Thus, 3HC-3-Tre permits rapid visualization of mycobacteria that ultimately could empower improved Mtb detection at the point-of-care in low-resource settings.

scholarly journals Utilizing selective chlorination to synthesize new triangulenium dyes

2021 ◽  
Author(s):  
Jesper Dahl Jensen ◽  
Niels Bisballe ◽  
Laura Kacenauskaite ◽  
Maria Storm Thomsen ◽  
Junsheng Chen ◽  
...  
Keyword(s):  
Early Stage ◽  
Quantum Yields ◽  
Electrophilic Aromatic Substitution ◽  
Fluorescence Lifetimes ◽  
Aromatic Substitution ◽  
Compound A ◽  
Fluorescence Quantum Yields ◽  
Reduction Potentials ◽  
Snar Reaction ◽  
High Fluorescence

Access to functionalization of new sites on the triangulenium core structure has been achieved at an early stage by chlorination with N-chlorosuccinimide (NCS), giving rise to two new triangulenium dyes (1 and 2). By introducing the chlorine functionalities in the acridinium precursor, positions complementary to those previously accessed by electrophilic aromatic substitution of the final dyes can be accesed. The chlorination is selective, giving only one regioisomer for both mono- and dichlorination products. For the monochlorinated acridinium compound a highly selective ring-closing reaction was discovered to generate only a single regioisomer of the cationic [4]helicene product. This discovery aspired further investigations into the mechanism of [4]helicene formation and to the first isolation of the previously proposed intermediate of the two-step SNAr reaction, key to all aza-bridged triangulenium and helicenium systems. A late stage functionalization of DAOTA+ with NCS gave rise to a different dichlorinated compound (2). The fully ring closed chlorinated triangulenium dyes 1, 2 and 3 show a redshift in absorption and emission relative to the non-chlorinated analogues, while still maintaining relatively high fluorescence quantum yields of 36%, 26%, and 41%, and long fluorescence lifetimes of 15 ns, 12.5 ns and 16 ns, respectively. Cyclic voltammetry shows that chlorination of the triangulenium dyes significantly lowers reduction potentials and thus allows for efficient tuning of redox and photo-redox properties.

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