Tripping the Light Fantastic: Organoboron Compounds

Elements ◽  
2017 ◽  
Vol 13 (4) ◽  
pp. 255-260
Author(s):  
Penelope J. Brothers
Keyword(s):  
Energy Transfer ◽  
Small Molecules ◽  
Materials Science ◽  
Chemical Reactivity ◽  
New Materials ◽  
Boron Compounds ◽  
Energy Medicine ◽  
Wide Range ◽  
Fluorescent Tags ◽  
Transfer Properties

Small molecules containing boron can play all sorts of roles in chemistry, biology and materials science. Molecular boron compounds display a wide range of unusual and fascinating structures, and their chemical reactivity can be very different from that of boron's next-door neighbour carbon. Some of the reasons for this will be considered and illustrated through applications in energy, medicine and new materials. The boron dipyrrins, also known as BODIPYs, are a prime example. They are strongly fluorescent when excited by illumination and are widely used as fluorescent tags in biology and as biosensors. More recently, they have been studied for their energy transfer properties in light-harvesting applications.

scholarly journals Perspective: plasmon antennas for nanoscale chiral chemistry

Nanophotonics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 481-489 ◽  
Author(s):  
Esteban Pedrueza-Villalmanzo ◽  
Francesco Pineider ◽  
Alexandre Dmitriev
Keyword(s):  
Energy Transfer ◽  
Materials Science ◽  
Decisive Role ◽  
Molecular Magnetism ◽  
Nanoscale Materials ◽  
Molecular Systems ◽  
Molecular Scale ◽  
Molecular Synthesis ◽  
Transfer Properties ◽  
The Way

AbstractPlasmon nanoantennas are extensively used with molecular systems for chemical and biological ultra-sensing, for boosting the molecular emissive and energy transfer properties, for nanoscale catalysis, and for building advanced hybrid nanoarchitectures. In this perspective, we focus on the latest developments of using plasmon nanoantennas for nanoscale chiral chemistry and for advancing molecular magnetism. We overview the decisive role nanoplasmonics and nano-optics can play in achieving chirally selective molecular synthesis and separation and the way such processes might be precisely controlled by potentially merging chirality and magnetism at the molecular scale. We give our view on how these insights might lead to the emergence of exciting new fundamental concepts in nanoscale materials science.

scholarly journals One mathematical model of thermal conductivity for materials with a granular structure

2019 ◽  
Vol 23 (Suppl. 4) ◽  
pp. 1273-1280
Author(s):  
Georgy Kuvyrkin ◽  
Inga Savelyeva ◽  
Daria Kuvshinnikova
Keyword(s):  
Thermal Conductivity ◽  
Materials Science ◽  
Internal State ◽  
Heat Conduction Problem ◽  
Irreversible Processes ◽  
New Materials ◽  
Wide Range ◽  
Important Direction ◽  
The Creation ◽  
Non Locality

The creation of new materials based on nanotechnology is an important direction of modern materials science development. Materials obtained by using nanotechnology can possess unique physicomechanical and thermophysical properties, al-lowing to use them effectively in structures exposed to high-intensity thermomechanical effects. An important step of the creation and usage of new materials is the construction of mathematical models to describe the behavior of these materials in a wide range of changes in external influences. One of the possible models for describing the process of thermal conductivity in structurally sensitive materials is proposed in this paper. The model is based on the laws of rational thermodynamics of irreversible processes and models of a continuous medium with internal state parameters. A qualitative study of the constructed model is carried out. A difference scheme is constructed in order to find the solution of the non-stationary heat conduction problem with allowance for the spatial non-locality effect. The analysis of the solutions is carried out.

Understanding Conformational Entropy in Small Molecules

2020 ◽  
Author(s):  
Lucian Chan ◽  
Garrett Morris ◽  
Geoffrey Hutchison
Keyword(s):  
Small Molecules ◽  
Degrees Of Freedom ◽  
Absolute Error ◽  
Low Energy ◽  
Standard Entropy ◽  
Free Energies ◽  
Conformational Entropy ◽  
Wide Range ◽  
High Degree ◽  
Empirical Corrections

The calculation of the entropy of flexible molecules can be challenging, since the number of possible conformers grows exponentially with molecule size and many low-energy conformers may be thermally accessible. Different methods have been proposed to approximate the contribution of conformational entropy to the molecular standard entropy, including performing thermochemistry calculations with all possible stable conformations, and developing empirical corrections from experimental data. We have performed conformer sampling on over 120,000 small molecules generating some 12 million conformers, to develop models to predict conformational entropy across a wide range of molecules. Using insight into the nature of conformational disorder, our cross-validated physically-motivated statistical model can outperform common machine learning and deep learning methods, with a mean absolute error ≈4.8 J/mol•K, or under 0.4 kcal/mol at 300 K. Beyond predicting molecular entropies and free energies, the model implies a high degree of correlation between torsions in most molecules, often as- sumed to be independent. While individual dihedral rotations may have low energetic barriers, the shape and chemical functionality of most molecules necessarily correlate their torsional degrees of freedom, and hence restrict the number of low-energy conformations immensely. Our simple models capture these correlations, and advance our understanding of small molecule conformational entropy.

scholarly journals The search for new materials and the role of novel processing routes

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Peter J. Wellmann
Keyword(s):  
Materials Science ◽  
Research Society ◽  
Subsequent Treatment ◽  
European Council ◽  
Trial And Error ◽  
Human History ◽  
New Materials ◽  
Materials Research ◽  
Novel Processing

AbstractThroughout human history, most further developments or new achievements were accompanied by new materials or new processes that enabled the technologic progress. With concrete devices and applications in mind, synthesis and subsequent treatment of materials naturally went along with the progress. The aim of the underlying article is to spot the role of optimization, of discovery, of trial-and-error approaches, of fundamentals and curiosity driven design and development. In a consecutive examination, five missions addressing the challenges facing our world (identified by the European Council) will be cross linked with seven topical areas from materials science defined by the European Materials Research Society. The scope of this examination is to identify approaches and methods to further develop and innovate materials which form the basis of the anticipated solutions.

scholarly journals Analysis of the possibility and molecular mechanism of carbon dioxide consumption in the Diels-Alder processes

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Karolina Kula ◽  
Agnieszka Kącka-Zych ◽  
Agnieszka Łapczuk-Krygier ◽  
Radomir Jasiński
Keyword(s):  
Carbon Dioxide ◽  
Molecular Mechanism ◽  
Lewis Acids ◽  
Chemical Reactivity ◽  
Carbon Dioxide Concentration ◽  
Diels Alder ◽  
Wide Range ◽  
Bet Analysis ◽  
Earth’S Climate ◽  
Step Mechanism

Abstract The large and significant increase in carbon dioxide concentration in the Earth’s atmosphere is a serious problem for humanity. The amount of CO2 is increasing steadily which causes a harmful greenhouse effect that damages the Earth’s climate. Therefore, one of the current trends in modern chemistry and chemical technology are issues related to its utilization. This work includes the analysis of the possibility of chemical consumption of CO2 in Diels-Alder processes under non-catalytic and catalytic conditions after prior activation of the C=O bond. In addition to the obvious benefits associated with CO2 utilization, such processes open up the possibility of universal synthesis of a wide range of internal carboxylates. These studies have been performed in the framework of Molecular Electron Density Theory as a modern view of the chemical reactivity. It has been found, that explored DA reactions catalyzed by Lewis acids with the boron core, proceeds via unique stepwise mechanism with the zwitterionic intermediate. Bonding Evolution Theory (BET) analysis of the molecular mechanism associated with the DA reaction between cyclopentadiene and carbon dioxide indicates that it takes place thorough a two-stage one-step mechanism, which is initialized by formation of C–C single bond. In turn, the DA reaction between cyclopentadiene and carbon dioxide catalysed by BH3 extends in the environment of DCM, indicates that it takes place through a two-step mechanism. First path of catalysed DA reaction is characterized by 10 different phases, while the second by eight topologically different phases.

scholarly journals Synthesis and Characterization of a Bioconjugate Based on Oleic Acid and L-Cysteine

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1791
Author(s):  
Marco Vizcarra-Pacheco ◽  
María Ley-Flores ◽  
Ana Mizrahim Matrecitos-Burruel ◽  
Ricardo López-Esparza ◽  
Daniel Fernández-Quiroz ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Materials Science ◽  
Critical Micellar Concentration ◽  
Synthesis And Characterization ◽  
New Materials ◽  
Visible Spectroscopy ◽  
Amide Bonds ◽  
Transmission Electron ◽  
Self Assembled

One of the main challenges facing materials science today is the synthesis of new biodegradable and biocompatible materials capable of improving existing ones. This work focused on the synthesis of new biomaterials from the bioconjugation of oleic acid with L-cysteine using carbodiimide. The resulting reaction leads to amide bonds between the carboxylic acid of oleic acid and the primary amine of L-cysteine. The formation of the bioconjugate was corroborated by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and nuclear magnetic resonance (NMR). In these techniques, the development of new materials with marked differences with the precursors was confirmed. Furthermore, NMR has elucidated a surfactant structure, with a hydrophilic part and a hydrophobic section. Ultraviolet-visible spectroscopy (UV-Vis) was used to determine the critical micellar concentration (CMC) of the bioconjugate. Subsequently, light diffraction (DLS) was used to analyze the size of the resulting self-assembled structures. Finally, transmission electron microscopy (TEM) was obtained, where the shape and size of the self-assembled structures were appreciated.

scholarly journals Melt-Spun Photoluminescent Polymer Optical Fibers for Color-Tunable Textile Illumination

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1740
Author(s):  
Konrad Jakubowski ◽  
Manfred Heuberger ◽  
Rudolf Hufenus
Keyword(s):  
Energy Transfer ◽  
Optical Fibers ◽  
Color Space ◽  
Emission Spectra ◽  
Wide Range ◽  
Color Tunable ◽  
Melt Spun ◽  
Polymer Optical Fibers ◽  
Collective Emission ◽  
Down Conversion

The increasing interest in luminescent waveguides, applied as light concentrators, sensing elements, or decorative illuminating systems, is fostering efforts to further expand their functionality. Yarns and textiles based on a combination of distinct melt-spun polymer optical fibers (POFs), doped with individual luminescent dyes, can be beneficial for such applications since they enable easy tuning of the color of emitted light. Based on the energy transfer occurring between differently dyed filaments within a yarn or textile, the collective emission properties of such assemblies are adjustable over a wide range. The presented study demonstrates this effect using multicolor, meltspun, and photoluminescent POFs to measure their superimposed photoluminescent emission spectra. By varying the concentration of luminophores in yarn and fabric composition, the overall color of the resulting photoluminescent textiles can be tailored by the recapturing of light escaping from individual POFs. The ensuing color space is a mean to address the needs of specific applications, such as decorative elements and textile illumination by UV down-conversion.

Harnessing methylation and AdoMet-utilising enzymes for selective modification in cascade reactions

2021 ◽  
Author(s):  
Freideriki Michailidou ◽  
Andrea Rentmeister
Keyword(s):  
Natural Products ◽  
Small Molecules ◽  
Cascade Reactions ◽  
Fine Tuning ◽  
Wide Range

Enzyme-mediated methylation is a very important reaction in nature, yielding a wide range of modified natural products, diversifying small molecules and fine-tuning the activity of biomacromolecules. The field has attracted...

scholarly journals Mini-review: antibody therapeutics targeting G protein-coupled receptors and ion channels

2020 ◽  
Vol 3 (4) ◽  
pp. 257-264
Author(s):  
Catherine J Hutchings
Keyword(s):  
Ion Channels ◽  
Research And Development ◽  
Small Molecules ◽  
G Protein ◽  
Clinical Studies ◽  
G Protein Coupled Receptors ◽  
Protein Targets ◽  
Antibody Therapeutics ◽  
Wide Range ◽  
G Protein Coupled

Abstract Antibodies are now well established as therapeutics with many additional advantages over small molecules and peptides relative to their selectivity, bioavailability, half-life and effector function. Major classes of membrane-associated protein targets include G protein-coupled receptors (GPCRs) and ion channels that are linked to a wide range of disease indications across all therapeutic areas. This mini-review summarizes the antibody target landscape for both GPCRs and ion channels as well as current progress in the respective research and development pipelines with some example case studies highlighted from clinical studies, including those being evaluated for the treatment of symptoms in COVID-19 infection.

scholarly journals Time-Resolved Measurements and Master Equation Modelling of the Unimolecular Decomposition of CH3OCH2

2020 ◽  
Vol 234 (7-9) ◽  
pp. 1233-1250 ◽  
Author(s):  
Arrke J. Eskola ◽  
Mark A. Blitz ◽  
Michael J. Pilling ◽  
Paul W. Seakins ◽  
Robin J. Shannon
Keyword(s):  
Energy Transfer ◽  
Master Equation ◽  
Rate Coefficient ◽  
Zero Point ◽  
Buffer Gas ◽  
Unimolecular Decomposition ◽  
Time Resolved ◽  
Point Energy ◽  
Wide Range ◽  
Transfer Parameters

AbstractThe rate coefficient for the unimolecular decomposition of CH3OCH2, k1, has been measured in time-resolved experiments by monitoring the HCHO product. CH3OCH2 was rapidly and cleanly generated by 248 nm excimer photolysis of oxalyl chloride, (ClCO)2, in an excess of CH3OCH3, and an excimer pumped dye laser tuned to 353.16 nm was used to probe HCHO via laser induced fluorescence. k1(T,p) was measured over the ranges: 573–673 K and 0.1–4.3 × 1018 molecule cm−3 with a helium bath gas. In addition, some experiments were carried out with nitrogen as the bath gas. Ab initio calculations on CH3OCH2 decomposition were carried out and a transition-state for decomposition to CH3 and H2CO was identified. This information was used in a master equation rate calculation, using the MESMER code, where the zero-point-energy corrected barrier to reaction, ΔE0,1, and the energy transfer parameters, ⟨ΔEdown⟩ × Tn, were the adjusted parameters to best fit the experimental data, with helium as the buffer gas. The data were combined with earlier measurements by Loucks and Laidler (Can J. Chem.1967, 45, 2767), with dimethyl ether as the third body, reinterpreted using current literature for the rate coefficient for recombination of CH3OCH2. This analysis returned ΔE0,1 = (112.3 ± 0.6) kJ mol−1, and leads to $k_{1}^{\infty}(T)=2.9\times{10^{12}}$ (T/300)2.5 exp(−106.8 kJ mol−1/RT). Using this model, limited experiments with nitrogen as the bath gas allowed N2 energy transfer parameters to be identified and then further MESMER simulations were carried out, where N2 was the buffer gas, to generate k1(T,p) over a wide range of conditions: 300–1000 K and N2 = 1012–1025 molecule cm−3. The resulting k1(T,p) has been parameterized using a Troe-expression, so that they can be readily be incorporated into combustion models. In addition, k1(T,p) has been parametrized using PLOG for the buffer gases, He, CH3OCH3 and N2.

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