scholarly journals Competitive Pi-Stacking and H-Bond Piling Increase Solubility of Heterocyclic Redoxmers

2020 ◽  
Vol 124 (46) ◽  
pp. 10409-10418 ◽  
Author(s):  
Yuyue Zhao ◽  
Erik S. Sarnello ◽  
Lily A. Robertson ◽  
Jingjing Zhang ◽  
Zhangxing Shi ◽  
...  
Keyword(s):  
Pi Stacking

The intermolecular anthracene-transfer in a regiospecific antipodal C60 difunctionalization

2020 ◽  
Author(s):  
Radu Talmazan ◽  
Klaus R. Liedl ◽  
Bernhard Kräutler ◽  
Maren Podewitz
Keyword(s):  
Noncovalent Interactions ◽  
Interaction Model ◽  
Alder Reaction ◽  
Diels Alder ◽  
Stacking Interactions ◽  
Pi Stacking ◽  
Diels Alder Reaction ◽  
Double Decker ◽  
Anthracene Molecule ◽  
New Strategies

We analyze the mechanism of the topochemically controlled difunctionalization of C60 and anthracene, where an anthracene molecule is transferred from one C60 monoadduct to another one under exclusive formation of equal amounts of C60 and the difficult to make antipodal C60 bisadduct. Our herein disclosed dispersion corrected DFT studies show the anthracene transfer to take place in a synchronous retro Diels-Alder/Diels-Alder reaction: an anthracene molecule dissociates from one fullerene under formation of an intermediate, while already undergoing stabilizing interactions with both neighboring fullerenes, facilitating the reaction kinetically. In the intermediate, a planar anthracene molecule is sandwiched between two neighboring fullerenes and forms equally strong "double-decker" type pi-pi stacking interactions with both of these fullerenes. Analysis with the distorsion interaction model shows that the anthracene unit of the intermediate is almost planar with minimal distorsions. This analysis sheds light on the existence of noncovalent interactions engaging both faces of a planar polyunsaturated ring and two convex fullerene surfaces in an unprecedented 'inverted sandwich' structure. Hence, it sheds light on new strategies to design functional fullerene based materials.<br>

The alternative strategy for designing covalent drugs through kinetic effects of pi-stacking on the self-assembled nanoparticles: a model study with antibiotics

2016 ◽  
Vol 27 (44) ◽  
pp. 445101 ◽  
Author(s):  
Libo Du ◽  
Siqingaowa Suo ◽  
Han Zhang ◽  
Hongying Jia ◽  
Ke Jian Liu ◽  
...  
Keyword(s):  
The Self ◽  
Alternative Strategy ◽  
Pi Stacking ◽  
Model Study ◽  
Self Assembled ◽  
Kinetic Effects

scholarly journals A Complete Assessment of Dopamine Receptor-Ligand Interactions through Computational Methods

2019 ◽  
Author(s):  
Beatriz Bueschbell ◽  
Carlos A.V. Barreto ◽  
Antonio J. Preto ◽  
Anke C. Schiedel ◽  
Irina S. Moreira
Keyword(s):  
Dopamine Receptor ◽  
Electrostatic Interactions ◽  
Specific Binding ◽  
Binding Pocket ◽  
Binding Mode ◽  
Receptor Subtypes ◽  
Receptor Ligand ◽  
Pi Stacking ◽  
Ligand Interactions ◽  
New Treatments

Background: Selectively targeting dopamine receptors has been a persistent challenge in the last years for the development of new treatments to combat the large variety of diseases evolving these receptors. Although, several drugs have been successfully brought to market, the subtype-specific binding mode on a molecular basis has not been fully elucidated. Methods: Homology modeling and molecular dynamics were applied to construct robust conformational models of all dopamine receptor subtypes (D1-like and D2-like receptors). Fifteen structurally diverse ligands were docked to these models. Contacts at the binding pocket were fully described in order to reveal new structural findings responsible for DR sub-type specificity. Results: We showed that the number of conformations for a receptor:ligand complex was associated to unspecific interactions &gt; 2.5 &Aring; and hydrophobic contacts, while the decoys binding energy was influenced by specific electrostatic interactions. Known residues such as 3.32Asp, the serine microdomain and the aromatic microdomain were found interacting in a variety of modes (HB, SB, &pi;-stacking). Purposed TM2-TM3-TM7 microdomain was found to form a hydrophobic network involving Orthosteric Binding Pocket (OBP) and Secondary Binding Pocket (SBP). T-stacking interactions revealed as especially relevant for some large ligands such as apomorphine, risperidone or aripiprazole. Conclusions: This in silico approach was successful in showing known receptor-ligand interactions as well as in determining unique combinations of interactions, key for the design of more specific ligands.

scholarly journals Covalent Organic Framework-Functionalized Magnetic CuFe2O4/Ag Nanoparticles for the Reduction of 4-Nitrophenol

2020 ◽  
Author(s):  
Chen Hou ◽  
Dongyan Zhao ◽  
Wenqiang Chen ◽  
Hao Li ◽  
Sufeng Zhang ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Silver Ions ◽  
Mesoporous Structure ◽  
Order Rate Constant ◽  
High Specific Surface Area ◽  
Stacking Interactions ◽  
First Order ◽  
Pi Stacking ◽  
Ordered Mesoporous ◽  
Nano Catalysts

In this work, magnetic CuFe2O4/Ag nanoparticles activated by porous covalent organic frameworks (COF) was fabricated to evaluate the heterogenous reduction of 4-nitrophenol (4-NP). The core-shell CuFe2O4/Ag@COF was successfully prepared by polydopamine reduction of silver ions on CuFe2O4 nanoparticles, followed by COF layer condensation. With integrating the intrinsic characteristics of the magnetic CuFe2O4/Ag core and COF layer, the obtained nanocomposite exhibited features of high specific surface area (464.21 m2 g-1), ordered mesoporous structure, strong environment stability, as well as fast magnetic response. Accordingly, the CuFe2O4/Ag@COF catalyst showed good affinity towards 4-NP via &pi;-&pi; stacking interactions and possessed enhanced catalytic activity compared with CuFe2O4/Ag and CuFe2O4@COF. The pseudo-first-order rate constant of CuFe2O4/Ag@COF (0.77 min-1) is 3 and 5 times higher than CuFe2O4/Ag and CuFe2O4@COF, respectively. The characteristics of bi-catalytic CuFe2O4/Ag and the porous COF shell of CuFe2O4/Ag@COF made a contribution to improve the activity of 4-NP reduction. The present work demonstrated a facile strategy to fabricate COF activated nano-catalysts with enhanced performance in the fields of nitrophenolic wastewater treatment.

Bioinspired catalysis and bromoperoxidase like activity of a multistimuli-responsive supramolecular metallogel: supramolecular assembly triggered by pi–pi stacking and hydrogen bonding interactions

2020 ◽  
Vol 44 (14) ◽  
pp. 5410-5418 ◽  
Author(s):  
Sunshine Dominic Kurbah ◽  
Ram A. Lal
Keyword(s):  
Hydrogen Bonding ◽  
Supramolecular Assembly ◽  
Synthesis And Characterization ◽  
Pi Stacking ◽  
Hydrogen Bonding Interactions ◽  
Bromination Reaction ◽  
Oxidative Bromination ◽  
Self Assembled

We report the synthesis and characterization of a new self-assembled VO2-L metallogel. Multi-responsive properties of the gel were also studied and can be used for sensing OH− anions. Bromoperoxidase-like activity of VO2-L metallogel for oxidative bromination reaction was also reported.

scholarly journals Photophysical properties of pyrrolocytosine, a cytosine fluorescent base analogue

2016 ◽  
Vol 18 (30) ◽  
pp. 20189-20198 ◽  
Author(s):  
Quynh L. Nguyen ◽  
Vincent A. Spata ◽  
Spiridoula Matsika
Keyword(s):  
Hydrogen Bonding ◽  
Ab Initio ◽  
Photophysical Properties ◽  
Fluorescence Properties ◽  
Water Molecules ◽  
Pi Stacking ◽  
High Level

The fluorescence properties of pyrrolocytosine, a cytosine analogue, are investigated using high level ab initio methods, and they are found to be affected by hydrogen bonding to water molecules, as well as by pi-stacking with guanine.

Role of reduced pi-pi stacking in the charge transport in polyfluorene

2016 ◽  
Vol 212 ◽  
pp. 62-70 ◽  
Author(s):  
Manisha Bajpai ◽  
Ritu Srivastava ◽  
Ravindra Dhar ◽  
R.S. Tiwari
Keyword(s):  
Charge Transport ◽  
Pi Stacking

scholarly journals Synthesis and Fluorescent Properties of Novel Mono- and Di-Substituted 1,8-Naphthalimide Derivatives at the C-4 Position

2017 ◽  
Author(s):  
Ying Fu ◽  
Xiao-Xiao Pang ◽  
Kui Wang ◽  
Zhi-Qiang Wang ◽  
Guan-Yu Li ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Chain Structure ◽  
Fluorescence Properties ◽  
Stacking Interactions ◽  
Fluorescent Properties ◽  
Enhanced Fluorescence ◽  
Pi Stacking ◽  
Molecular Core ◽  
Long Chain

A series of novel N-n-butyl-1,8-naphthalimide derivatives were synthesized via a three-step reaction involving nucleophilic substitution and acylation. All of the compounds were characterized by IR, 1H NMR, 13C NMR, MS, and elemental analysis, and the crystal structure of N-n-butyl-4-[N&rsquo;,N&rsquo;-bis(2`,4`-dichlorobenzoyl)ethylamino]-1,8-naphthalimide was determined. The &pi;-&pi; stacking interactions and hydrogen bonds between the two molecular core planes (naphthalimide ring) and the van der Waals forces between the flexible n-butyl groups resulted in a 3D long-chain structure. The UV-vis and fluorescence properties of the title compounds were investigated. The results indicated that the monosubstituted 1,8-naphthalimide derivatives bearing an electron-donating group on the benzene ring or a structure with a larger conjugative effect exhibited enhanced fluorescence properties.

scholarly journals Comparative analysis of the unbinding pathways of antiviral drug Indinavir from HIV and HTLV1 proteases by Supervised Molecular Dynamics simulation

2021 ◽  
Author(s):  
Farzin Sohraby ◽  
Hassan Aryapour
Keyword(s):  
Inhibitory Activity ◽  
Antiviral Drug ◽  
Good Explanation ◽  
Dynamics Simulation ◽  
Stacking Interactions ◽  
Pi Stacking ◽  
Efficacious Treatment ◽  
The Stability ◽  
Flap Region ◽  
Hiv 1

Determining the unbinding pathways of potential small molecule compounds from their target proteins is of great significance for designing efficacious treatment solutions. One of these potential compounds is the approved HIV-1 protease inhibitor, indinavir, which has a weak effect on the HTLV-1 protease. In this work, by employing SuMD method, we reconstructed the unbinding pathways of indinavir from HIV and HTLV-1 proteases in order to compare and to understand the mechanism of the unbinding, and also to discover the reasons for the lack of inhibitory activity of indinavir against the HTLV-1 protease. We achieved multiple unbinding events from both HIV and HTLV-1 proteases in which the RMSD values of indinavir reached over 4 nm. Also, we found that the mobility and the fluctuations of the flap region is higher in the HTLV-1 protease which makes the drug less stable. We realized that critically positioned aromatic residues such as Trp98/Trp98' and Phe67/Phe67' in the HTLV-1 protease can make strong pi-Stacking interactions with indinavir in the unbinding pathway which are unfavorable for the stability of indinavir in the active site. The details found in this study can make a good explanation for the lack of inhibitory activity of this drug against HTLV-1 protease. We believe the details discovered in this work can be a great assist for designing more effective and more selective inhibitors for the HTLV-1 protease.

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