Search results for "Fluorescence"

ChemInform Abstract: Boron Functionalization of BODIPY by Various Alcohols and Phenols

2014

The synthesis of new B–O BODIPY derivatives functionalized with different alkoxy or diarylalkoxy derivatives is described. These compounds were synthesized from the reaction of different B–F BODIPY precursors with various alcohols and phenols, in the presence of AlCl3. Water-soluble dyes could be synthesized as well with this method, specifically by the introduction of polyethyleneglycol (PEG) groups. A photophysical study of the different compounds was performed, and showed that the B–O BODIPY derivatives exhibit rich fluorescence properties. Finally, the conjugation of the BODIPY core has been extended using two distyryl groups, hence providing NIR emitting BODIPY derivatives, in which on…

Evaluation of remote sensing of vegetation fluorescence by the analysis of diurnal cycles

2008

Chlorophyll fluorescence (ChF) emission is a direct indicator of the photosynthetic activity of vegetation, which is a key parameter of the carbon cycle. This paper analyses chlorophyll fluorescence evolution at leaf level during a complete diurnal cycle in simulated and natural conditions, for two species under different stress conditions. Absolute spectral radiance of the ChF emission is obtained allowing a quantitative derivation of the fluorescence yield of the ChF, which correlates well with established fluorescence instruments. The studied cases show that the ChF emission is mainly driven by the photosynthetic active radiation during the whole cycle, but the fluorescence yield is seve…

Diaryldistyrylpyrazines: Solvatochromic and Acidochromic Fluorophores

2013

Diaryldimethylpyrazines are the starting materials for the synthesis of C2-symmetric donor- or acceptor-substituted distyrylpyrazines. The optical properties of these cruciform-shaped dyes are dominated by the distyrylpyrazine units; the photophysics is controlled by the styryl substitution, the diaryl substituents on the central pyrazine only having a small effect. Protonation occurs on the pyrazine and/or lateral amines or azines, thereby altering the absorption and emission properties. Hypso- and bathochromism as well as fluorescence quenching depend on the nature of the terminal substituent. This, and a significant positive solvatochromism of the fluorescence, allow optical sensing of t…

PHOSPHORORGANISCHE VERBINDUNGEN 1091DIE SYNTHESE FLUORESZIERENDER REAGENTIEN MIT CHEMOSELEKTIVEN ANKERGRUPPEN

1984

Abstract A route for the synthesis of type B-compounds is reported. Compound 5 is a strong fluorescent and is O-selective. Type C-compounds, for example 10a to 10d show a high fluorescence and are O-selective. They are obtained via 6 and 7 (n=2–4,6; R=Me, X=F). Boc-serine is O-phosphonylated by the methyl-phosphonicacid-esterfluorides, for example 10c. ω-(9-Acridinyl)alkyl-phosphonicacid-alkyl-esterfluorides, like 22, are available in only moderate yields via 15a-e as intermediates. More but unsuccessful experiments for the synthesis of fluorescent and O-selective acridine compounds are reported shortly. Die Synthese von Verbindungen vom Typ B wird beschrieben. Die Verbindung 5 verbindet Fl…

Through-bond versus through-space T1 energy transfers in organometallic compound-metalloporphyrin pigments

2009

The preparation and characterization of two d9−d9 M2-bonded Pt2(dppm)2(C≡CC6H4-M(P))2 complexes (where M = Zn or Pd, and P = diethylhexamethylporphyrin) were achieved. The central [Pt2(dppm)2(C≡CC6H4)2] organometallic unit appears to be an independent chromophore and is suspected to be luminescent at 77 K (in 2MeTHF) in the porphyrin-containing complexes, as this is the case for the unfunctionalized Pt2(dppm)2(C≡CPh)2 parent compound. However, when this spacer is connected (by a single C−C bond) to either M(P) (M = Zn, Pd), even in the absence of conjugation (as the computed dihedral angle between the C6H4 and porphyrin planes is ∼84.5°), total quenching of the luminescence of the [Pt2(dppm…

A New pH-Dependent Macrocyclic Rhodamine B-Based Fluorescent Probe for Copper Detection in White Wine

2019

For efficiently measuring copper (II) ions in the acidic media of white wine, a new chemosensor based on rhodamine B coupled to a tetraazamacrocyclic ring (13aneN4CH2NH2) was designed and synthesized by a one-pot reaction using ethanol as a green solvent. The obtained chemosensor was characterized via NMR, UV and fluorescent spectra. It was marked with no color emission under neutral pH conditions, with a pink color emission under acidic conditions, and a magenta color emission under acidic conditions where copper (II) ions were present. The sensitivity towards copper (II) ions was tested and verified over Ca2+, Ag+, Zn2+, Mg2+, Co2+, Ni2+, Fe2+, Pb2+, Cd2+, Fe3+, and Mn2+, with a detection…

Effect of nanoaquacitrates on physiological parameters of Fodder Galega infected with phytoplasma

2018

The laboratory experiments have been found that so aking seeds Galega orientalis L. (Fodder galega) in nanoaquacitrates solutions of Mn (10 and 20 mg/dm 3), Mo (4 mg/dm3) and Mg (2 and 4 mg/dm3), has been lead to germination energy rise, while Mn( 10 and 20 mg/dm3) and Mo (4 mg/dm3) concentrations has been influenced germinating ability. At the same time, the soaking seeds in solution of nanoaquacitrates Mn (20 mg/dm3) had the biggest stimulatory effect on the accumulation 7 daily sprouts mass (on 18%). It has been shown that s oaking seeds in nanoparticles Mn and Mo solutions leads to the increase of catalase activities (especially under the influence of manganese) and peroxidase activitie…

Interactive effects of boron and salinity on greenhouse tomato grown in closed soilless system.

2012

Removal of Chromophore-proximal Polar Atoms Decreases Water Content and Increases Fluorescence in a Near Infrared Phytofluor

2015

Genetically encoded fluorescent markers have revolutionized cell and molecular biology due to their biological compatibility, controllable spatiotemporal expression, and photostability. To achieve in vivo imaging in whole animals, longer excitation wavelength probes are needed due to the superior ability of near infrared light to penetrate tissues unimpeded by absorbance from biomolecules or autofluorescence of water. Derived from near infrared-absorbing bacteriophytochromes, phytofluors are engineered to fluoresce in this region of the electromagnetic spectrum, although high quantum yield remains an elusive goal. An invariant aspartate residue is of utmost importance for photoconversion in…

First Chemosensor for Selective Detection and Quantification of L-4-Hydroxyproline in Collagen and Other Bio Samples.

2017

Amino pyridine-based rhodamine conjugate (APR) has been developed as a first chemosensor for selective detection and quantification of L-4-Hydroxyproline (Hyp). The “turn-on” fluorescence property of the chemosensor makes it unique for easy estimation of Hyp in collagen and biological samples. peerReviewed