Fluorescence detected linear dichroism of small molecules oriented on polyethylene film

The Analyst ◽  
2018 ◽  
Vol 143 (23) ◽  
pp. 5805-5811
Author(s):  
A. M. Wemyss ◽  
K. Razmkhah ◽  
N. P. Chmel ◽  
A. Rodger
Keyword(s):  
Solid State ◽  
Small Molecules ◽  
Fluorescence Emission ◽  
Linear Dichroism ◽  
Polyethylene Film ◽  
Emission Data ◽  
Additional Information ◽  
Oriented Molecules

We demonstrate that by measuring the fluorescence emission data during a linear dichroism measurement, one obtains additional information on the exited state properties and interactions of oriented molecules in the solid state.

A Free Energy Perturbation Approach to Estimate the Intrinsic Solubilities of Drug-like Small Molecules

2019 ◽  
Author(s):  
Sayan Mondal ◽  
Gary Tresadern ◽  
Jeremy Greenwood ◽  
Byungchan Kim ◽  
Joe Kaus ◽  
...  
Keyword(s):  
Solid State ◽  
Small Molecules ◽  
Three Dimensional ◽  
Aqueous Solubility ◽  
Computational Approach ◽  
Free Energy Perturbation ◽  
Perturbation Approach ◽  
Energy Perturbation ◽  
State Form ◽  
Good Agreement

<p>Optimizing the solubility of small molecules is important in a wide variety of contexts, including in drug discovery where the optimization of aqueous solubility is often crucial to achieve oral bioavailability. In such a context, solubility optimization cannot be successfully pursued by indiscriminate increases in polarity, which would likely reduce permeability and potency. Moreover, increasing polarity may not even improve solubility itself in many cases, if it stabilizes the solid-state form. Here we present a novel physics-based approach to predict the solubility of small molecules, that takes into account three-dimensional solid-state characteristics in addition to polarity. The calculated solubilities are in good agreement with experimental solubilities taken both from the literature as well as from several active pharmaceutical discovery projects. This computational approach enables strategies to optimize solubility by disrupting the three-dimensional solid-state packing of novel chemical matter, illustrated here for an active medicinal chemistry campaign.</p>

scholarly journals Multichannel near-field nanoscopy of circular and linear dichroism at the solid-state

2016 ◽  
Author(s):  
G. Lazzini ◽  
M. Castriciano ◽  
M. Trapani ◽  
N. Micali ◽  
F. Tantussi ◽  
...  
Keyword(s):  
Solid State ◽  
Near Field ◽  
Linear Dichroism

scholarly journals Deep search for hydrogen peroxide toward pre- and protostellar objects

2020 ◽  
Vol 636 ◽  
pp. A114
Author(s):  
G. W. Fuchs ◽  
D. Witsch ◽  
D. Herberth ◽  
M. Kempkes ◽  
B. Stanclik ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Solid State ◽  
Water Reservoir ◽  
Reaction Network ◽  
Reaction Scheme ◽  
Young Stellar Objects ◽  
Model Parameters ◽  
Stellar Objects ◽  
Additional Information ◽  
Water Formation

Context. In the laboratory, hydrogen peroxide (HOOH) was proven to be an intermediate product in the solid-state reaction scheme that leads to the formation of water on icy dust grains. When HOOH desorbs from the icy grains, it can be detected in the gas phase. In combination with water detections, it may provide additional information on the water reaction network. Hydrogen peroxide has previously been found toward ρ Oph A. However, further searches for this molecule in other sources failed. Hydrogen peroxide plays a fundamental role in the understanding of solid-state water formation and the overall water reservoir in young stellar objects (YSOs). Without further HOOH detections, it is difficult to assess and develop suitable chemical models that properly take into account the formation of water on icy surfaces. Aims. The objective of this work is to identify HOOH in YSOs and thereby constrain the grain surface water formation hypothesis. Methods. Using an astrochemical model based on previous work in combination with a physical model of YSOs, the sources R CrA-IRS 5A, NGC C1333-IRAS 2A, L1551-IRS 5, and L1544 were identified as suitable candidates for an HOOH detection. Long integration times on the APEX 12 m and IRAM 30 m telescopes were applied to search for HOOH signatures in these sources. Results. None of the four sources under investigation showed convincing spectral signatures of HOOH. The upper limit for HOOH abundance based on the noise level at the frequency positions of this molecule for the source R CrA-IRS 5A was close to the predicted value. For NGC 1333-IRAS 2A, L1544, and L1551-IRS 5, the model overestimated the hydrogen peroxide abundances. Conclusions. HOOH remains an elusive molecule. With only one secure cosmic HOOH source detected so far, namely ρ Oph A, the chemical model parameters for this molecule cannot be sufficiently well determined or confirmed in existing models. Possible reasons for the nondetections of HOOH are discussed.

scholarly journals Impact of nanosizing a host matrix based on a metal–organic framework on solid-state fluorescence emission and energy transfer

2022 ◽  
Author(s):  
Hikaru Sakamoto ◽  
Akitaka Ito ◽  
Masataka Ohtani
Keyword(s):  
Energy Transfer ◽  
Solid State ◽  
Metal Organic Framework ◽  
Fluorescence Emission ◽  
Dye Molecules ◽  
Host Matrix ◽  
Metal Organic ◽  
Solid State Fluorescence ◽  
Organic Framework

We demonstrate that the nanosize effect appears to affect the properties of dye molecules encapsulated in the pores of a metal–organic framework (dye@MOF). The emissive properties of the nanosized dye@MOF...

Adsorption of Small Molecules on Cu3(btc)2 and Cu3–xZnx(btc)2 Metal–Organic Frameworks (MOF) As Studied by Solid-State NMR

2013 ◽  
Vol 117 (15) ◽  
pp. 7703-7712 ◽  
Author(s):  
Farhana Gul-E-Noor ◽  
Matthias Mendt ◽  
Dieter Michel ◽  
Andreas Pöppl ◽  
Harald Krautscheid ◽  
...  
Keyword(s):  
Solid State ◽  
Small Molecules ◽  
Solid State Nmr ◽  
Metal Organic Frameworks ◽  
Metal Organic

Tetrahedra from Aryleneethenylenes – From small Molecules to Luminescent Glasses

2004 ◽  
Vol 814 ◽  
Author(s):  
H. Detert ◽  
O. Sadovski ◽  
Erli Sugiono
Keyword(s):  
Solid State ◽  
Small Molecules ◽  
Electronic Spectra ◽  
Central Atom ◽  
Aromatic Aldehydes ◽  
Dense Packing ◽  
Electronic Interaction ◽  
Glass Transitions ◽  
Conjugated Systems ◽  
Open Structures

AbstractThe fourfold Horner olefination of tetraphenylmethane or –silane with fourp-methyl- phosphonate groups and a variety of aromatic aldehydes with donor groups or extended conjugated systems results in the formation of tetrahedra from four chromophores connected via a central atom. Electronic spectra in solution reveal an electronic interaction between the π-systems. In the solid state, the emission of compounds with a dense packing is nearly identical to the solution spectra, more open structures show significant red shifts. The emission of scaffolds with 1-styrylpyrene chromophores is nearly completely quenched. Most of these tetrahedra are thermally stable up to 420°C. Depending on the diameter of the scaffold, glass transitions occur between 99°C and 169°C.

Studies on fluorescence of cellulosics

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 504-508 ◽  
Author(s):  
Alain Castellan ◽  
Reinaldo Ruggiero ◽  
Elisabete Frollini ◽  
Ludmila A. Ramos ◽  
Christine Chirat
Keyword(s):  
Solid State ◽  
Microcrystalline Cellulose ◽  
Woody Plants ◽  
Average Molecular Weight ◽  
Homogeneous Medium ◽  
Fluorescence Emission ◽  
Excitation Wavelength ◽  
Experimental Conditions ◽  
Fluorescence Emission Spectra ◽  
Cotton Linters

Abstract Steady-state fluorescence emission spectra of various celluloses were measured at an excitation wavelength of 320 nm. Various spectra recorded in the solid state were compared: (1) ECF bleached papers made of hardwood, the anhydroglucose units of which were chemically modified at C1 and C6 or C2 and C3 positions with carboxylic groups; (2) microcrystalline cellulose; (3) cotton linters; and (4) delignified sisal fibers (mercerized or not). Fluorescence emission was quite independent of the carboxylic acid content and average molecular weight (determined by viscosimetry) of the cellulose polymers. Microcrystalline cellulose (Avicel), cotton linters, and mercerized delignified sisal cellulose were acetylated in homogeneous medium (DMAc/LiCl as solvent system) to obtain soluble polymers in dichloromethane for comparison of spectra recorded in the solid and liquid states. Fluorescence of cellulose acetates in solution (CH2Cl2) and in the solid state was compared under similar experimental conditions to non-esterified celluloses in the solid state. The importance of the solid state for fluorescence emission could be demonstrated. Fluorophores are present in minute amounts in the polymer and their favorable energy transfer for excitation in the solid state likely enhances fluorescence emission. Among numerous fluorophores, dityrosine appeared to be a good candidate for fluorescence because it displayed emission in the fluorescence range of cellulose. Dityrosine is an amino acid involved in the lignification of non-woody plants. Mercerized sisal impregnated with tyrosine in the presence of peroxidase and hydrogen peroxide did not show enhanced emission, in contrast to para-hydroxycinnamic acid (coumaric acid), which is also involved in the lignification process at least for non-woody plants. The origin of cellulose fluorescence remains uncertain and appears to have several origins. This study clearly underlines the importance of the solid state for enhancing fluorophore emission.

Solid State Fluorescence Emission of Aflatoxins on Silica Gel

1968 ◽  
Vol 51 (6) ◽  
pp. 1190-1192
Author(s):  
James A Robertson ◽  
Walter A Pons
Keyword(s):  
Solid State ◽  
Silica Gel ◽  
Fluorescence Emission ◽  
Solid State Fluorescence

Abstract The solid state fluorescence emission maxima of aflatoxins B1, B2, G1, and G2 on silica gel range from 427 to 455 mµ, with excitation maxima at 368—369 mµ. Both the order and the magnitude of the relative fluorescence intensities of individual aflatoxins are different in solution and in the solid state on silica gel.

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