Molecular modeling of porphyrin-based conjugates and subphthalocyanine aggregates

2009 ◽  
Vol 13 (04n05) ◽  
pp. 494-508 ◽  
Author(s):  
Víctor R. Ferro ◽  
Luis A. Poveda ◽  
Rafael Lopez ◽  
José M. García de la Vega
Keyword(s):  
Charge Separation ◽  
Theoretical Study ◽  
Theoretical Models ◽  
Structural Features ◽  
New Materials ◽  
Potential Applications ◽  
Donor Acceptor ◽  
The Stability ◽  
Porphyrin Dimers

A theoretical study was carried out on both porphyrin-based conjugates (with interest in the so-called artificial photosynthesis) and subphthalocyanine aggregates (with potential applications as new materials for optoelectronics, solar energy and other uses). A simple molecular orbital model for studying the role of the spacer groups in the electron transfer in porphyrin-quinone conjugates was developed. The influence of the π-π interaction, hydrogen association and covalent linkage on the stability and structural features in porphyrin-porphyrin complexes as well as the charge separation in donor-acceptor porphyrin dimers, were reproduced. Theoretical models suggest the potential feasibility of SubPc's aggregative processes leading to nanometer-sized fully aromatic fullerene-like molecular architectures.

scholarly journals A G2(MP2) theoretical study of substituent effects on H3BNHnCl3−n (n= 3-0) donor-acceptor complexes

2008 ◽  
Vol 6 (3) ◽  
pp. 400-403 ◽  
Author(s):  
Hafid Anane ◽  
Soufiane Houssame ◽  
Abdelali Guerraze ◽  
Abdeladim Guermoune ◽  
Abderrahim Boutalib ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Substituent Effects ◽  
Lone Pair ◽  
Proton Affinities ◽  
Lone Pair Orbital ◽  
Chlorine Substitution ◽  
Donor Acceptor ◽  
Nitrogen Lone Pair ◽  
The Stability ◽  
N Compounds

AbstractThe complexation energies of H3BNHnCl3−n (n= 3-0) complexes and the proton affinities of NHnCl3−n compounds have been computed at the G2(MP2) level of theory. G2(MP2) results show that the successive chlorine substitution on the ammonia decreases both the basicity of the NHnCl3−n ligands and the stability of H3BNHnCl3−n complexes. The findings are interpreted in terms of the rehybridisation of the nitrogen lone-pair orbital. The NBO partitioning scheme shows that the variation of the N-H and N-Cl bond lengths, upon complexation, is due to variation of “s” character in these bonds.

Controlling charge separation and recombination by chemical design in donor–acceptor dyads

2016 ◽  
Vol 18 (27) ◽  
pp. 18536-18548 ◽  
Author(s):  
Li Liu ◽  
Pierre Eisenbrandt ◽  
Thomas Roland ◽  
Matthias Polkehn ◽  
Pierre-Olivier Schwartz ◽  
...  
Keyword(s):  
Solar Cells ◽  
Organic Solar Cells ◽  
Charge Separation ◽  
Chemical Design ◽  
Potential Applications ◽  
Donor Acceptor

Conjugated donor–acceptor block co-oligomers that self-organize into D–A mesomorphic arrays have raised increasing interest due to their potential applications in organic solar cells.

scholarly journals Settling the matter of the role of vibrations in the stability of high-entropy carbides

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Marco Esters ◽  
Corey Oses ◽  
David Hicks ◽  
Michael J. Mehl ◽  
Michal Jahnátek ◽  
...  
Keyword(s):  
Chemical Stability ◽  
Nearest Neighbor ◽  
Configurational Entropy ◽  
New Materials ◽  
Decomposition Products ◽  
Thermodynamic Characterization ◽  
High Entropy ◽  
Significant Interest ◽  
The Stability

AbstractHigh-entropy ceramics are attracting significant interest due to their exceptional chemical stability and physical properties. While configurational entropy descriptors have been successfully implemented to predict their formation and even to discover new materials, the contribution of vibrations to their stability has been contentious. This work unravels the issue by computationally integrating disorder parameterization, phonon modeling, and thermodynamic characterization. Three recently synthesized carbides are used as a testbed: (HfNbTaTiV)C, (HfNbTaTiW)C, and (HfNbTaTiZr)C. It is found that vibrational contributions should not be neglected when precursors or decomposition products have different nearest-neighbor environments from the high-entropy carbide.

scholarly journals Sc3N@Ih-C80 based donor–acceptor conjugate: role of thiophene spacer in promoting ultrafast excited state charge separation

RSC Advances ◽  
2020 ◽  
Vol 10 (34) ◽  
pp. 19861-19866
Author(s):  
Rubén Caballero ◽  
Luis David Servián ◽  
Habtom B. Gobeze ◽  
Olivia Fernandez-Delgado ◽  
Luis Echegoyen ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Separation ◽  
Charge Recombination ◽  
Photoinduced Charge Separation ◽  
Donor Acceptor ◽  
Photoinduced Charge ◽  
State Charge

Photoinduced charge separation and dark charge recombination occurring within picoseconds is observed in newly synthesized triphenylamine–thiophene-Sc3N@Ih-C80 and triphenylamine–thiophene-C60 conjugates.

Role of glycosylation in nucleating protein folding and stability

2017 ◽  
Vol 474 (14) ◽  
pp. 2333-2347 ◽  
Author(s):  
Nisha Grandhi Jayaprakash ◽  
Avadhesha Surolia
Keyword(s):  
Structural Features ◽  
Folding Kinetics ◽  
Post Translational Modification ◽  
Disease States ◽  
Degenerative Disorders ◽  
Health And Disease ◽  
Folded Proteins ◽  
Complex Forms ◽  
The Stability

Glycosylation constitutes one of the most common, ubiquitous and complex forms of post-translational modification. It commences with the synthesis of the protein and plays a significant role in deciding its folded state, oligomerization and thus its function. Recent studies have demonstrated that N-linked glycans help proteins to fold as the stability and folding kinetics are altered with the removal of the glycans from them. Several studies have shown that it alters not only the thermodynamic stability but also the structural features of the folded proteins modulating their interactions and functions. Their inhibition and perturbations have been implicated in diseases from diabetes to degenerative disorders. The intent of this review is to provide insight into the recent advancements in the general understanding on the aspect of glycosylation driven stability of proteins that is imperative to their function and finally their role in health and disease states.

scholarly journals Revealing the role of Pb2+ in the stability of organic–inorganic hybrid perovskite CH3NH3Pb1−xCdxI3: an experimental and theoretical study

2015 ◽  
Vol 17 (37) ◽  
pp. 23886-23896 ◽  
Author(s):  
Javier Navas ◽  
Antonio Sánchez-Coronilla ◽  
Juan Jesús Gallardo ◽  
Elisa I. Martín ◽  
Norge C. Hernández ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Theoretical Study ◽  
Inorganic Hybrid ◽  
Hybrid Perovskite ◽  
The Stability

Experimental and theoretical analysis revealing the role of Pb2+ in the stability of organic–inorganic hybrid perovskites.

The Role of Distress Disclosure Tendencies in the Experience and Expression of Laboratory-Induced Sadness

2017 ◽  
Vol 38 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Jeffrey H. Kahn ◽  
Daniel W. Cox ◽  
A. Myfanwy Bakker ◽  
Julia I. O’Loughlin ◽  
Agnieszka M. Kotlarczyk
Keyword(s):  
Individual Differences ◽  
Emotional Reactivity ◽  
Subjective Experience ◽  
Negative Emotion ◽  
Theoretical Models ◽  
Laboratory Research ◽  
Emotion Words ◽  
Distress Disclosure ◽  
Computerized Text Analysis

Abstract. The benefits of talking with others about unpleasant emotions have been thoroughly investigated, but individual differences in distress disclosure tendencies have not been adequately integrated within theoretical models of emotion. The purpose of this laboratory research was to determine whether distress disclosure tendencies stem from differences in emotional reactivity or differences in emotion regulation. After completing measures of distress disclosure tendencies, social desirability, and positive and negative affect, 84 participants (74% women) were video recorded while viewing a sadness-inducing film clip. Participants completed post-film measures of affect and were then interviewed about their reactions to the film; these interviews were audio recorded for later coding and computerized text analysis. Distress disclosure tendencies were not predictive of the subjective experience of emotion, but they were positively related to facial expressions of sadness and happiness. Distress disclosure tendencies also predicted judges’ ratings of the verbal disclosure of emotion during the interview, but self-reported disclosure and use of positive and negative emotion words were not associated with distress disclosure tendencies. The authors present implications of this research for integrating individual differences in distress disclosure with models of emotion.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

The Role of Hydrophobicity in the Stability and pH-Switchability of (RXDX)4 and Coumarin-RXDX Conjugate β-Sheets

2020 ◽  
Author(s):  
Ryan Weber ◽  
Martin McCullagh
Keyword(s):  
Biological Imaging ◽  
Ph Sensing ◽  
Hydrophobic Residue ◽  
Ideal Candidate ◽  
Self Assembling ◽  
Sensing Applications ◽  
Β Sheets ◽  
The Stability ◽  
Dynamics Simulations

<p>pH-switchable, self-assembling materials are of interest in biological imaging and sensing applications. Here we propose that combining the pH-switchability of RXDX (X=Ala, Val, Leu, Ile, Phe) peptides and the optical properties of coumarin creates an ideal candidate for these materials. This suggestion is tested with a thorough set of all-atom molecular dynamics simulations. We first investigate the dependence of pH-switchabiliy on the identity of the hydrophobic residue, X, in the bare (RXDX)<sub>4</sub> systems. Increasing the hydrophobicity stabilizes the fiber which, in turn, reduces the pH-switchabilty of the system. This behavior is found to be somewhat transferable to systems in which a single hydrophobic residue is replaced with a coumarin containing amino acid. In this case, conjugates with X=Ala are found to be unstable and both pHs while conjugates with X=Val, Leu, Ile and Phe are found to form stable β-sheets at least at neutral pH. The (RFDF)<sub>4</sub>-coumarin conjugate is found to have the largest relative entropy value of 0.884 +/- 0.001 between neutral and acidic coumarin ordering distributions. Thus, we posit that coumarin-(RFDF)<sub>4</sub> containing peptide sequences are ideal candidates for pH-sensing bioelectronic materials.</p>

Sign in / Sign up

Export Citation Format

Share Document