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.

Near-infrared Ag2Se quantum dots with distinct absorption features and high fluorescence quantum yields

RSC Advances ◽  
2016 ◽  
Vol 6 (44) ◽  
pp. 38183-38186 ◽  
Author(s):  
Li-Juan Shi ◽  
Chun-Nan Zhu ◽  
He He ◽  
Dong-Liang Zhu ◽  
Zhi-Ling Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Near Infrared ◽  
Quantum Yields ◽  
Extinction Coefficients ◽  
Fluorescence Quantum Yields ◽  
High Fluorescence ◽  
Absorption Features ◽  
Molar Extinction Coefficients

Near-infrared Ag2Se QDs with distinct absorption features ranging between 830–954 nm and fluorescence quantum yields up to 23.4% were controllably synthesized, and the molar extinction coefficients of the Ag2Se QDs were determined.

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 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.

scholarly journals Fluorescent Liquid Tetrazines

Molecules ◽  
2021 ◽  
Vol 26 (19) ◽  
pp. 6047
Author(s):  
Maximilian Paradiz Paradiz Dominguez ◽  
Begüm Demirkurt ◽  
Marion Grzelka ◽  
Daniel Bonn ◽  
Laurent Galmiche ◽  
...  
Keyword(s):  
Photophysical Properties ◽  
Liquid Films ◽  
Quantum Yields ◽  
Intersystem Crossing ◽  
Time Resolved ◽  
Fluorescence Quantum Yields ◽  
Exciton Migration ◽  
Orange Fluorescence ◽  
The Difference ◽  
Chain Lengths

Tetrazines with branched alkoxy substituents are liquids at ambient temperature that despite the high chromophore density retain the bright orange fluorescence that is characteristic of this exceptional fluorophore. Here, we study the photophysical properties of a series of alkoxy-tetrazines in solution and as neat liquids. We also correlate the size of the alkoxy substituents with the viscosity of the liquids. We show using time-resolved spectroscopy that intersystem crossing is an important decay pathway competing with fluorescence, and that its rate is higher for 3,6-dialkoxy derivatives than for 3-chloro-6-alkoxytetrazines, explaining the higher fluorescence quantum yields for the latter. Quantum chemical calculations suggest that the difference in rate is due to the activation energy required to distort the tetrazine core such that the nπ*S1 and the higher-lying ππ*T2 states cross, at which point the spin-orbit coupling exceeding 10 cm−1 allows for efficient intersystem crossing to occur. Femtosecond time-resolved anisotropy studies in solution allow us to measure a positive relationship between the alkoxy chain lengths and their rotational correlation times, and studies in the neat liquids show a fast decay of the anisotropy consistent with fast exciton migration in the neat liquid films.

Photochemical cross sections in cytidylyl-(3′-5′)-cytidine

1968 ◽  
Vol 46 (8) ◽  
pp. 911-918 ◽  
Author(s):  
P. V. Hariharan ◽  
H. E. Johns
Keyword(s):  
Cross Sections ◽  
Quantum Yields ◽  
Important Class ◽  
Extinction Coefficients ◽  
Dark Reaction ◽  
Dna And Rna ◽  
Biological Interest ◽  
Thymine Dimers ◽  
The Cross ◽  
Molar Extinction Coefficients

Ultraviolet irradiation of cytidylyl-(3′-5′)-cytidine (CpC) results in the production of only one dimer, [Formula: see text], and for ultraviolet exposures in the range of biological interest, only the single hydrate (CpC)*. A second dimer of CpC, [Formula: see text], arises from [Formula: see text] through a dark reaction. Both these dimers deaminate in the dark to dimers of uridylyl-(3′-5′)-cytidine (UpC) and then to [Formula: see text]. The cross sections and quantum yields for the production of [Formula: see text] and (CpC)* have been determined at a number of wavelengths. In the wavelength range 240–289 mμ, the cross sections for dimer production are at least two times that for hydrate production. Approximate molar extinction coefficients have been determined for a mixture of [Formula: see text] and [Formula: see text], yielding values at ail wavelengths which are at least four times larger than for thymine dimers. The cross sections for dimer reversal of [Formula: see text] and [Formula: see text] are about the same and are larger than those of thymine dimers by at least a factor of 6.0. The quantum yield for reversal of CpC dimers is about 1.0 and independent of wavelength. These photochemical findings prove that in CpC, dimers are a much more important class of photoproduct than hydrates at low ultraviolet exposures. A similar result could be expected in polymers containing cytosine such as occur in DNA and RNA.

scholarly journals Correlating structural and photochemical heterogeneity in cyanobacteriochrome NpR6012g4

2018 ◽  
Vol 115 (17) ◽  
pp. 4387-4392 ◽  
Author(s):  
Sunghyuk Lim ◽  
Qinhong Yu ◽  
Sean M. Gottlieb ◽  
Che-Wei Chang ◽  
Nathan C. Rockwell ◽  
...  
Keyword(s):  
Structural Changes ◽  
Control Plant ◽  
Structural Heterogeneity ◽  
Site Directed Mutagenesis ◽  
Structural Basis ◽  
Quantum Yields ◽  
Shade Avoidance ◽  
Dark State ◽  
Time Resolved ◽  
Fluorescence Quantum Yields

Phytochrome photoreceptors control plant growth, development, and the shade avoidance response that limits crop yield in high-density agricultural plantings. Cyanobacteriochromes (CBCRs) are distantly related photosensory proteins that control cyanobacterial metabolism and behavior in response to light. Photoreceptors in both families reversibly photoconvert between two photostates via photoisomerization of linear tetrapyrrole (bilin) chromophores. Spectroscopic and biochemical studies have demonstrated heterogeneity in both photostates, but the structural basis for such heterogeneity remains unclear. We report solution NMR structures for both photostates of the red/green CBCR NpR6012g4 from Nostoc punctiforme. In addition to identifying structural changes accompanying photoconversion, these structures reveal structural heterogeneity for residues Trp655 and Asp657 in the red-absorbing NpR6012g4 dark state, yielding two distinct environments for the phycocyanobilin chromophore. We use site-directed mutagenesis and fluorescence and absorbance spectroscopy to assign an orange-absorbing population in the NpR6012g4 dark state to the minority configuration for Asp657. This population does not undergo full, productive photoconversion, as shown by time-resolved spectroscopy and absorption spectroscopy at cryogenic temperature. Our studies thus elucidate the spectral and photochemical consequences of structural heterogeneity in a member of the phytochrome superfamily, insights that should inform efforts to improve photochemical or fluorescence quantum yields in the phytochrome superfamily.

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).

Photodissociation of ClONO2:  2. Time-Resolved Absorption Studies of Product Quantum Yields

1997 ◽  
Vol 101 (36) ◽  
pp. 6667-6678 ◽  
Author(s):  
R. J. Yokelson ◽  
James B. Burkholder ◽  
R. W. Fox ◽  
A. R. Ravishankara
Keyword(s):  
Quantum Yields ◽  
Time Resolved ◽  
Absorption Studies

scholarly journals Indenopyrans – synthesis and photoluminescence properties

2016 ◽  
Vol 12 ◽  
pp. 825-834 ◽  
Author(s):  
Andreea Petronela Diac ◽  
Ana-Maria Ţepeş ◽  
Albert Soran ◽  
Ion Grosu ◽  
Anamaria Terec ◽  
...  
Keyword(s):  
Solid State ◽  
Emission Band ◽  
Fluorescence Spectra ◽  
Photophysical Properties ◽  
Quantum Yields ◽  
Band Broadening ◽  
Photoluminescence Properties ◽  
Fluorescence Quantum Yields ◽  
Blue Emitters ◽  
Solid State Fluorescence

New indeno[1,2-c]pyran-3-ones bearing different substituents at the pyran moiety were synthesized and their photophysical properties were investigated. In solution all compounds were found to be blue emitters and the trans isomers exhibited significantly higher fluorescence quantum yields (relative to 9,10-diphenylanthracene) as compared to the corresponding cis isomers. The solid-state fluorescence spectra revealed an important red shift of λmax due to intermolecular interactions in the lattice, along with an emission-band broadening, as compared to the solution fluorescence spectra.

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.

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