Luminescence Spectral Properties of New Benzothiazole Polymethine Dye

Abstract

The absorption and fl uorescence spectra of a new styryl derivative of thiofl avin T 2-{(1E,3E)-4- in solvents with diff erent polarity and viscosity and also incorporated in the structure of amyloid fi brils and bovine serum albumin were investigated. A characteristic feature of the dye is an extremely low quantum yield of fl uorescence in low-viscosity solvents (10 -4 in water) which, however, increases signifi cantly in viscous solutions and when it is incorporated in the structure of proteins or amyloid fi brils. In the latter case the quantum yield increases by 8•10 3 times. On the basis of the experimental studies and quantum chemical calculations it was shown that Th-C23 exhibits the properties of a molecular rotor. The increase of the fl uorescence quantum yield in viscous solutions and in the biopolymers results from limitation of the torsional rotation of the molecular fragments, leading to fl uorescence quenching. The longwavelength location of the absorption spectrum and the fl uorescence spectrum of the new dye in the red region of the spectrum (520 and 600 nm) makes it possible to use it as a fl uorescent marker that is sensitive to the viscosity (hardness) of the microenvironment not only in vitro but also in vivo.

Spectral Fluorescence Pathology of Protein Misfolding Disorders

“…While bright-field microscopy remains the most widespread technique for microscopic tissue examination, fluorescence offers enhanced contrast, higher sensitivity, and specificity for molecular species of interest. The discovery of certain small organic molecules binding to and reporting amyloids continued with the application of thioflavins T and S and the synthesis of structurally similar probes. − Following the discovery of the proteins that make up amyloid plaques, neurofibrillary tangles, and Lewy bodies in AD and PD, Aβ-, tau-, and α-synuclein-specific antibodies were developed to specifically visualize their distribution in the brain.…”

Oxide Metamorphic Manganese Ores: An Experimental Results of Heat Treatment

“…It is used to produce trimanganese tetraoxide, which is used in producing light brown, yellow-brown, brown, and dark brown bricks, ceramic products, paving slabs, etc. Synthetic hausmannite as a pigment can be used for staining in mass and surface staining [23,24]. Compared with pyrolusite, it significantly increases efficiency, reducing the harmfulness and labor intensity of the process [23].…”

Pd(II)- and Pt(II)-Assisted P–C Activation/Cyclization Reactions with a Luminescent α-Aminophosphine

“…Metal ions in these cases are Ru­(II), Rh­(III), Ir­(III), or Ni­(II); α-aminophosphines bear morpholine, piperazine, or carboxyphenyl substituents at the N atom. ,, Meantime, metal-assisted synthesis can facilitate transformations in ligands, yielding novel architectures, which are otherwise difficult to access. , Therefore, our motivation in this work is to find novel metal-assisted P–C bond activation paths for aminophosphines, especially for luminescent ones, which comprise a photophysically active sulfur–nitrogen heterocycle. In this context, we chose a 2-phenylbenzothiazolyl ( Pbt ) chromophore, whose derivatives are widely used in the design of photoluminescent materials. − They reveal interesting photophysical features, such as excited-state intramolecular proton transfer (ESIPT) , and aggregate-induced emission (AIE). , A new Pbt -based α-methylaminophosphine ( PCN , 1 ) designed in our work has not been synthesized to date, although an oxidized congener, α-methylaminophosphine oxide, and its luminescent Zn complexes were reported recently . Benefiting from coordination to harder Lewis acids, phosphine oxides, however, are generally less prone to coordinate with softer Pd­(II) and Pt­(II) ions.…”