scholarly journals Towards low-energy-light-driven bistable photoswitches: ortho-fluoroaminoazobenzenes

2021 ◽  
Author(s):  
Kim Kuntze ◽  
Jani Viljakka ◽  
Evgenii Titov ◽  
Zafar Ahmed ◽  
Elina Kalenius ◽  
...  
Keyword(s):  
Visible Light ◽  
Excited States ◽  
Quantum Chemical ◽  
Low Energy ◽  
Living Systems ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Thermal Stability Of ◽  
Insight Into ◽  
Cis Isomer

Abstract Thermally stable photoswitches that are driven with low-energy light are rare, yet crucial for extending the applicability of photoresponsive molecules and materials towards, e.g., living systems. Combined ortho-fluorination and -amination couples high visible-light absorptivity of o-aminoazobenzenes with the extraordinary bistability of o-fluoroazobenzenes. Herein, we report a library of easily accessible o-aminofluoroazobenzenes and establish structure–property relationships regarding spectral qualities, visible light isomerization efficiency and thermal stability of the cis-isomer with respect to the degree of o-substitution and choice of amino substituent. We rationalize the experimental results with quantum chemical calculations, revealing the nature of low-lying excited states and providing insight into thermal isomerization. The synthesized azobenzenes absorb at up to 600 nm and their thermal cis-lifetimes range from milliseconds to months. The most unique example can be driven from trans to cis with any wavelength from UV up to 595 nm, while still exhibiting a thermal cis-lifetime of 81 days.

scholarly journals Towards low-energy-light-driven bistable photoswitches: ortho-fluoroaminoazobenzenes

2021 ◽  
Author(s):  
Kim Kuntze ◽  
Jani Viljakka ◽  
Evgenii Titov ◽  
Zafar Ahmed ◽  
Elina Kalenius ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Visible Light ◽  
Excited States ◽  
Quantum Chemical ◽  
Low Energy ◽  
Living Systems ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Thermal Stability Of ◽  
Insight Into

AbstractThermally stable photoswitches that are driven with low-energy light are rare, yet crucial for extending the applicability of photoresponsive molecules and materials towards, e.g., living systems. Combined ortho-fluorination and -amination couples high visible light absorptivity of o-aminoazobenzenes with the extraordinary bistability of o-fluoroazobenzenes. Herein, we report a library of easily accessible o-aminofluoroazobenzenes and establish structure–property relationships regarding spectral qualities, visible light isomerization efficiency and thermal stability of the cis-isomer with respect to the degree of o-substitution and choice of amino substituent. We rationalize the experimental results with quantum chemical calculations, revealing the nature of low-lying excited states and providing insight into thermal isomerization. The synthesized azobenzenes absorb at up to 600 nm and their thermal cis-lifetimes range from milliseconds to months. The most unique example can be driven from trans to cis with any wavelength from UV up to 595 nm, while still exhibiting a thermal cis-lifetime of 81 days. Graphical abstract

Crystal and electronic structure of the new ternary phosphide Ho5Pd19P12

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Olha Zhak ◽  
Oksana Karychort ◽  
Volodymyr Babizhetskyy ◽  
Chong Zheng
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Structure Property Relationships ◽  
Metallic Bonding ◽  
Crystal And Electronic Structure ◽  
Insight Into

Abstract The title compound was prepared from the pure elements by sintering. The crystal structure was investigated by means of powder X-ray diffraction data. Ho5Pd19P12 exhibits the hexagonal Ho5Ni19P12-type structure with space group P 6 ‾ 2 m $P‾{6}2m$ , a = 13.1342(2), c = 3.9839(1) Å, R I = 0.060, R p = 0.080. The crystal structure can be described as a combination of two types of the structural units, [HoPd6P3] and [Ho3Pd10P6], respectively, mutually displaced by 1/2 along the crystallographic c axis. Quantum chemical calculations have been performed to analyze the electronic structure and provide deeper insight into the structure-property relationships. The results of the quantum chemical calculations indicate that the material features metallic bonding between Ho and Pd and covalent bonding between Pd and P.

Influence of Structural Organization On Optical and Transport Properties in Organic Materials

1999 ◽  
Vol 598 ◽  
Author(s):  
J. Cornil ◽  
J.Ph. Calbert ◽  
D. Beljonne ◽  
D.A. Dos Santos ◽  
J.L. Bredas
Keyword(s):  
Transport Properties ◽  
Quantum Chemical Calculations ◽  
Quantum Chemical ◽  
Structural Organization ◽  
Conjugated Oligomers ◽  
Structure Property ◽  
Chain Packing ◽  
Crystalline Phases ◽  
Structure Property Relationships ◽  
Insight Into

ABSTRACTCorrelated quantum-chemical calculations performed on supermolecular structures, i.e., on clusters made of several oligomer chains in interaction, provide insight into structure-property relationships in well-organized molecular films. This supermolecular approach is applied to crystalline phases of two prototypical conjugated oligomers and shows that variations in chain packing can lead to dramatically different optical (Davydov) splittings and carrier mobilities. Optimal chain organizations for various types of devices are discussed.

Structure-Property Relationships of Core-Substituted Diaryl Dihydrophenazine Organic Photoredox Catalysts and their Application in O-ATRP

2021 ◽  
Author(s):  
Mariel Jene Price ◽  
Katrina Puffer ◽  
Max Kudisch ◽  
Declan Knies ◽  
Garret Miyake
Keyword(s):  
Visible Light ◽  
Atom Transfer Radical Polymerization ◽  
Radical Polymerization ◽  
Controlled Radical Polymerization ◽  
Low Energy ◽  
Atom Transfer ◽  
Structure Property ◽  
Structure Property Relationships

Photoinduced organocatalyzed atom-transfer radical polymerization (O-ATRP) is a controlled radical polymerization technique that can be driven using low-energy, visible light and makes use of organic photocatalysts. Limitations of O-ATRP have...

Charge Transport Properties in Discotic Liquid Crystals:  A Quantum-Chemical Insight into Structure−Property Relationships

2004 ◽  
Vol 126 (10) ◽  
pp. 3271-3279 ◽  
Author(s):  
Vincent Lemaur ◽  
Demetrio A. da Silva Filho ◽  
Veaceslav Coropceanu ◽  
Matthias Lehmann ◽  
Yves Geerts ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Charge Transport ◽  
Transport Properties ◽  
Quantum Chemical ◽  
Discotic Liquid Crystals ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Insight Into

scholarly journals Energetics of LOHC: Structure-Property Relationships from Network of Thermochemical Experiments and in Silico Methods

Hydrogen ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 101-121
Author(s):  
Sergey P. Verevkin ◽  
Vladimir N. Emel’yanenko ◽  
Riko Siewert ◽  
Aleksey A. Pimerzin
Keyword(s):  
In Silico ◽  
Quantum Chemical ◽  
Structure Property ◽  
Chemical Methods ◽  
Key Technology ◽  
Structure Property Relationships ◽  
Quantum Chemical Methods ◽  
Dehydrogenation Reactions ◽  
Storage Technologies ◽  
In Silico Methods

The storage of hydrogen is the key technology for a sustainable future. We developed an in silico procedure, which is based on the combination of experimental and quantum-chemical methods. This method was used to evaluate energetic parameters for hydrogenation/dehydrogenation reactions of various pyrazine derivatives as a seminal liquid organic hydrogen carriers (LOHC), that are involved in the hydrogen storage technologies. With this in silico tool, the tempo of the reliable search for suitable LOHC candidates will accelerate dramatically, leading to the design and development of efficient materials for various niche applications.

Structure/Property Relationships of Seashells

2004 ◽  
Vol 844 ◽  
Author(s):  
David J. Scurr ◽  
Stephen J. Eichhorn
Keyword(s):  
Raman Band ◽  
Surface Damage ◽  
Structure Property ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structure Property Relationships ◽  
Energy Variable ◽  
Insight Into ◽  
Characterisation Techniques ◽  
Scanning Electron

ABSTRACTThis study uses various characterisation techniques on the razor shell (Ensis siliqua), to relate the shell's microstructure to its mechanical properties. Scanning electron microscopy (SEM) has shown that the outer and inner regions of the shell are composed of simple and complex crossed lamellar microstructures respectively. These layers are interspersed by prismatic layers of a completely different crystallographic orientation. Nanoindentation and microhardness measurements have shown that the structure is anisotropic, and Raman band shifts have been observed within these indented/deformed areas of shell, showing that the microstructure deforms rather than generating surface damage. The use of energy variable synchrotron X-ray diffraction has shown that the calcium carbonate crystals of the shell are preferentially orientated as a function of depth and that opposing residual stresses exist at the outer and inner regions of the shell. This study has analysed several microstructural features of the shell and provided an insight into how they prevent failure of the material.

Corrole basicity in the excited states: Insights on structure–property relationships

2020 ◽  
Vol 24 (05n07) ◽  
pp. 765-774
Author(s):  
Mikalai M. Kruk ◽  
Dmitry V. Klenitsky ◽  
Lev L. Gladkov ◽  
Wouter Maes
Keyword(s):  
Excited States ◽  
Conformational Changes ◽  
Pyrrole Ring ◽  
Point Of View ◽  
Free Base ◽  
Structure Property ◽  
Substitution Pattern ◽  
Long Wavelength ◽  
Structure Property Relationships ◽  
Fluorescence Measurements

Steady-state fluorescence measurements and quantum-chemical DFT geometry optimizations are applied to extend the structure–property relationships between the free-base corrole macrocycle conformation and its basicity to the lowest excited S[Formula: see text] and T[Formula: see text] states. Direct basicity estimation in the lowest excited S[Formula: see text] state is demonstrated by means of fluorescence quantum yield measurements. The long wavelength T1 tautomer is found to retain its basicity in the S[Formula: see text] state, whereas the short wavelength T2 tautomer shows a noticeable decrease in basicity in the S[Formula: see text] state, which is related to the in-plane tilting of the pyrrole ring to be protonated. The conformational changes upon going from the ground to the lowest excited T[Formula: see text] state and the influence of the meso-aryl substitution pattern on the overall degree of distortions and tilting of the pyrrole ring to be protonated are also discussed from the point of view of macrocycle basicity.

When Current Does Not Follow Bonds: Current Density in Saturated Molecules

2019 ◽  
Author(s):  
Anders Jensen ◽  
Marc Hamilton Garner ◽  
Gemma C. Solomon
Keyword(s):  
Spatial Distribution ◽  
Current Density ◽  
Current Flow ◽  
Structure Property ◽  
Conjugated Molecules ◽  
Structure Property Relationships ◽  
Electron Transport Properties ◽  
Current Flows ◽  
Molecular Conductance ◽  
Insight Into

<div> <div> <div> <p>The tools commonly used to understand structure-property relationships in molecular conductance, inter-atomic currents and conductance eigenchannels, generally give us a sense of familiarity, with the chemical bonding framework and molecular orbitals reflected in the current. Here we show that while this picture is true for conjugated molecules, it breaks down in saturated systems. We investigate the current density in saturated chains of alkanes, silanes and germanes and show that the current density does not follow the bonds, but rather the nuclei define the diameter of a pipe through which the current flows. We discuss how this picture of current density can be used to understand details about the electron transport properties of these molecules. Understanding the spatial distribution of current through molecules, rather than simply the magnitude, provides a powerful tool for chemical insight into physical properties of molecules that are related to current flow. </p> </div> </div> </div>

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