Pd doping, conformational, and charge effects on the dichroic response of a monolayer protected Au38(SR)24 nanocluster

2019 ◽  
Vol 21 (7) ◽  
pp. 3585-3596 ◽  
Author(s):  
Daniele Toffoli ◽  
Oscar Baseggio ◽  
Giovanna Fronzoni ◽  
Mauro Stener ◽  
Alessandro Fortunelli ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Optical Response ◽  
Cd Spectra ◽  
Charge Effects ◽  
End Groups ◽  
Pd Doping ◽  
Charge States ◽  
Conformational Degrees Of Freedom

TDDFT simulations of the absorption and CD spectra of a Pd2Au36(SC2H4Ph)24 monolayer-protected cluster (MPC) are carried out with the aim of investigating the effects of doping, conformational degrees of freedom of the thiolates’ end-groups, and charge states on its chiro-optical response.

scholarly journals Computational High-Throughput Screening of Polymeric Photocatalysts: Exploring the Effect of Composition, Sequence Isomerism and Conformational Degrees of Freedom

2018 ◽  
Author(s):  
isabelle Heath-Apostolopoulos ◽  
Liam Wilbraham ◽  
Martijn Zwijnenburg
Keyword(s):  
High Throughput ◽  
High Throughput Screening ◽  
Degrees Of Freedom ◽  
Chemical Space ◽  
Low Cost ◽  
Computational Screening ◽  
Computational Workflow ◽  
Conformational Degrees Of Freedom

We discuss a low-cost computational workflow for the high-throughput screening of polymeric photocatalysts and demonstrate its utility by applying it to a number of challenging problems that would be difficult to tackle otherwise. Specifically we show how having access to a low-cost method allows one to screen a vast chemical space, as well as to probe the effects of conformational degrees of freedom and sequence isomerism. Finally, we discuss both the opportunities of computational screening in the search for polymer photocatalysts, as well as the biggest challenges.

Synthesis and properties of macrocyclic diazene switch with binaphthalene unit attached via acrylamide linkers

2013 ◽  
Vol 67 (1) ◽  
Author(s):  
Anna Kicková ◽  
Branislav Horváth ◽  
Lukáš Kerner ◽  
Martin Putala
Keyword(s):  
Methyl Acrylate ◽  
Heck Reaction ◽  
Knoevenagel Condensation ◽  
Equimolar Mixture ◽  
Cd Spectra ◽  
Photostationary State ◽  
End Groups

Abstract2,2′-Diiodo-1,1′-binaphthalene undergoes a tandem Heck reaction with methyl acrylate to afford methyl 2-(7H-dibenzo[c,g]fluoren-7-ylidene)acetate. As a consequence, the target macrocyclic diazene with binaphthalene unit attached via acrylamide linker was prepared by the stepwise building of acrylamide at a binaphthalene moiety, including the Doebner modification of the Knoevenagel condensation, and completed by oxidative macrocyclisation of aniline end-groups. Despite being an equimolar mixture of monomer and dimer, it exhibited remarkable changes in CD spectra due to reversible (E/Z) isomerisation of N=N diazene bonds upon irradiation at 365/465 nm. Although the dimer isomerises from (E) to (Z) isomer 7.4 times faster than the monomer, the latter’s contribution to the change in ellipticity at 307 nm in the photostationary state is 2.4 times greater.

scholarly journals Decoupling of crystalline and conformational degrees of freedom in lipid monolayers

1989 ◽  
Vol 91 (3) ◽  
pp. 1855-1865 ◽  
Author(s):  
John Hjort Ipsen ◽  
Ole G. Mouritsen ◽  
Martin J. Zuckermann
Keyword(s):  
Degrees Of Freedom ◽  
Lipid Monolayers ◽  
Conformational Degrees Of Freedom

scholarly journals Criticality of Lamellar Surfaces by Conformational Degrees of Freedom

1995 ◽  
Vol 5 (9) ◽  
pp. 1161-1178
Author(s):  
B. Bassetti ◽  
G. Mazzoletti ◽  
P. Jona
Keyword(s):  
Degrees Of Freedom ◽  
Conformational Degrees Of Freedom

Conformational Entropy as a Means to Control the Behavior of Poly(diketonenamine) Vitrimers In and Out of Equilibrium

2019 ◽  
Author(s):  
Changfei He ◽  
Peter Christensen ◽  
Trevor Seguin ◽  
Brandon Wood ◽  
Kristin Persson ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Characteristic Time ◽  
Degrees Of Freedom ◽  
Freezing Temperature ◽  
Thermomechanical Behavior ◽  
Polymer Chains ◽  
Network Density ◽  
Conformational Entropy ◽  
Conformational Degrees Of Freedom

Here we show how to control the thermomechanical behavior of vitrimers, both in and out of equilibrium, by incorporating into the dynamic covalent network linear polymer segments varying in both molecular weight (MW = 0–12 kg mol–1) and conformational degrees of freedom. While increasing MW of linear segments predictably yields a lower storage modulus (E’) at the rubbery plateau after softening above the glass transition (Tg), due to the lower network density, we further find that both Tg and the characteristic time (t*) of stress-relaxation when deformed are independently governed by the conformational entropy of the embodied linear segments. We also find that activation energies (Ea) for vitrimer bond exchange in the solid-state are lower, by as much as 19 kJ mol−1, for networks incorporating flexible chains, and that the network’s topology freezing temperature (Tv) decreases with increasing MW of flexible linear segments, but increases with increasing MW of stiff linear segments. Therefore, the dynamics of vitrimer reconfigurability are influenced not only by the energetics of associative bond exchange for a given network density, but also foundationally by the entropy of polymer chains within the network.

scholarly journals Role of Geometric Shape in Chiral Optics

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 158
Author(s):  
Philipp Gutsche ◽  
Xavier Garcia-Santiago ◽  
Philipp-Immanuel Schneider ◽  
Kevin M. McPeak ◽  
Manuel Nieto-Vesperinas ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Activity ◽  
Degrees Of Freedom ◽  
Optical Response ◽  
Point Of View ◽  
Geometric Shape ◽  
Constructive Method ◽  
High Interest ◽  
T Matrix

The distinction of chiral and mirror symmetric objects is straightforward from a geometrical point of view. Since the biological as well as the optical activity of molecules strongly depend on their handedness, chirality has recently attracted high interest in the field of nano-optics. Various aspects of associated phenomena including the influences of internal and external degrees of freedom on the optical response have been discussed. Here, we propose a constructive method to evaluate the possibility of observing any chiral response from an optical scatterer. Based on solely the T-matrix of one enantiomer, planes of minimal chiral response are located and compared to geometric mirror planes. This provides insights into the relation of geometric and optical properties and enables identifying the potential of chiral scatterers for nano-optical experiments.

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