scholarly journals Understanding Ring Puckering in Small Molecules and Cyclic Peptides

2020 ◽  
Author(s):  
Lucian Chan ◽  
Geoffrey Hutchison ◽  
Garrett Morris
Keyword(s):  
Small Molecules ◽  
Cyclic Peptides ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Drug Binding ◽  
Torsion Angles ◽  
Ring Puckering ◽  
Physical And Chemical ◽  
Ring Conformations ◽  
General Ring

<div>The geometry of a molecule plays a significant role in determining its physical and chemical properties. Despite its importance, there are relatively few studies on ring puckering and conformations, often focused on small cycloalkanes, five- and six-membered carbohydrate rings and specific macrocycle families. We lack a general understanding of the puckering preferences of medium-sized rings and macrocycles. To address this, we provide an extensive conformational analysis of a diverse set of rings. We used Cremer-Pople puckering coordinates to study the trends of the ring conformation across a set of 140,000 diverse small molecules, including small rings, macrocycles and cyclic peptides. By standardizing using key atoms, we show that the ring conformations can be classified into relatively few conformational clusters, based on their canonical forms. The number of such canonical clusters increases slowly with ring size. Ring puckering motions, especially pseudo-rotations, are generally restricted, and differ between clusters. More importantly, we propose models to map puckering preferences to torsion space, which allows us to understand the interrelated changes in torsion angles during pseudo-rotation and other puckering motions. Beyond ring puckers, our models also explain the change in substituent orientation upon puckering. In summary, this work provides an improved understanding of general ring puckering preferences, which will in turn accelerate the identification of low energy ring conformations for applications from polymeric materials to drug binding.</div>

scholarly journals Understanding Ring Puckering in Small Molecules and Cyclic Peptides

2020 ◽  
Author(s):  
Lucian Chan ◽  
Geoffrey Hutchison ◽  
Garrett Morris
Keyword(s):  
Small Molecules ◽  
Cyclic Peptides ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Drug Binding ◽  
Torsion Angles ◽  
Ring Puckering ◽  
Physical And Chemical ◽  
Ring Conformations ◽  
General Ring

<div>The geometry of a molecule plays a significant role in determining its physical and chemical properties. Despite its importance, there are relatively few studies on ring puckering and conformations, often focused on small cycloalkanes, five- and six-membered carbohydrate rings and specific macrocycle families. We lack a general understanding of the puckering preferences of medium-sized rings and macrocycles. To address this, we provide an extensive conformational analysis of a diverse set of rings. We used Cremer-Pople puckering coordinates to study the trends of the ring conformation across a set of 140,000 diverse small molecules, including small rings, macrocycles and cyclic peptides. By standardizing using key atoms, we show that the ring conformations can be classified into relatively few conformational clusters, based on their canonical forms. The number of such canonical clusters increases slowly with ring size. Ring puckering motions, especially pseudo-rotations, are generally restricted, and differ between clusters. More importantly, we propose models to map puckering preferences to torsion space, which allows us to understand the interrelated changes in torsion angles during pseudo-rotation and other puckering motions. Beyond ring puckers, our models also explain the change in substituent orientation upon puckering. In summary, this work provides an improved understanding of general ring puckering preferences, which will in turn accelerate the identification of low energy ring conformations for applications from polymeric materials to drug binding.</div>

Effects of electronic and recoil processes in polymers during ion implantation

1994 ◽  
Vol 9 (4) ◽  
pp. 1043-1050 ◽  
Author(s):  
E. H. Lee ◽  
G. R. Rao ◽  
M. B. Lewis ◽  
L. K. Mansur
Keyword(s):  
Energy Transfer ◽  
Ion Implantation ◽  
Cross Sections ◽  
Linear Energy Transfer ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Track Length ◽  
Property Changes ◽  
Physical And Chemical ◽  
Ion Species

It has been shown that ion implantation produces remarkable improvements in surface-sensitive mechanical properties, as well as other physical and chemical properties in polymers. To understand mechanisms underlying such property changes, various polymeric materials were subjected to bombardment by energetic ions in the range of 200 keV to 2 MeV. The magnitude of property changes is strongly dependent upon ion species, energy, and dose. Analysis indicated that hardness and electrical conductivity increased by employing ion species with larger electronic cross sections and with increasing ion energy and dose. The results showed that electronic stopping or linear energy transfer (LET, energy deposited per unit track length per ion) for ionization was the most important factor for the enhancement of hardness, while nuclear stopping or linear energy transfer for displacement generally appeared to reduce hardness.

scholarly journals Understanding Ring Puckering in Small Molecules and Cyclic Peptides

2021 ◽  
Vol 61 (2) ◽  
pp. 743-755 ◽  
Author(s):  
Lucian Chan ◽  
Geoffrey R. Hutchison ◽  
Garrett M. Morris
Keyword(s):  
Small Molecules ◽  
Cyclic Peptides ◽  
Ring Puckering

scholarly journals Influence of NaCl on the polymerization of vinyl monomers by the suspension process

2019 ◽  
pp. 19-23
Author(s):  
Erika Montero ◽  
David Contreras-López ◽  
Rosalba Fuentes ◽  
María Del Rosario Galindo
Keyword(s):  
Batch Reactor ◽  
Research Work ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Operating Conditions ◽  
Suspension Process ◽  
Different Types ◽  
Physical And Chemical ◽  
And Chemical Properties

The production of artificial polymers is, today, one of themost important activities of the chemical industry, polymersare widely used in everyday life, as, there are different types of polymers, they can be used for different uses. These polymeric materials have unique mechanical, physical and chemical properties, which most other materials do not possess, not to mention that its cost is lower than the other materials. The present research work focuses on the determination of optimal operating conditions for the polymerization of styrene and methyl methacrylate in a Batch reactor, as well as the influence of inorganic salt in this case NaCl in the performance of reaction and in the size of the material polymer, through the process of suspension using a synthetic route of polymerization by radical free conventional (FRP), where viscometry to the polymeric material testing was performed for this way characterize it, and to determine factors of interest such as the molecular weight, etc.

scholarly journals Novelty Designed Hybrid Organic-Inorganic Nanocomposites from Functional Palm Oil

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Suryani Suryani
Keyword(s):  
Thermal Stability ◽  
Palm Oil ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
Domain Structures ◽  
Wide Range ◽  
Inorganic Nanocomposites ◽  
Physical And Chemical

Polyurethanes (PUs) are very versatile polymeric materials with a wide range of physical and chemical properties. PUs also have desirable properties such as high abrasion resistance, tear strength, shock absorption, flexibility and elasticity. Although they have poor thermal stability that however can be improved by using treated clay. The objective of the present work is to study the thermal stability of polyurethane, polyurethane/montmorillonite (PU CTAB-mont 3% wt) and polyurethane/montmorillonite that contain moca nanocomposites are based on palm oil polyol. The interest of investigating the synthesis of polyurethane/clay nanocomposites based on palm oil polyol is to explore the use of palm oil polyol to replace petrochemical based polyol partially. Polyurethane/clay nanocomposites were prepared by a pre-polymer method and were evaluated by fourier transform infrared spectra (FTIR) to determine micro-domain structures of segmented PU, PU CTAB-mont 3% wt, and PU Moca CTAB-mont 3% wt. The morphology of the nanocomposites were characterized by X-ray diffraction (X-RD) and flame retardant was investigated with thermogravimetric analysis (TGA). The result showed that adding clay and moca demonstrated better thermal stability in comparison with the virgin polyurethane.Keywords : Nanocomposite, polyurethane, synthesis, palm oil polyol

scholarly journals Implementation of a remote laboratory for the identification of polymeric materials by means of physical properties analysis

2021 ◽  
Vol 2102 (1) ◽  
pp. 012008
Author(s):  
C O Vargas-Mantilla ◽  
W Palacios-Alvarado ◽  
B Medina-Delgado
Keyword(s):  
Physical Properties ◽  
Engineering Students ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Experimental Tests ◽  
Nonparametric Tests ◽  
Point Of View ◽  
Remote Laboratory ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract Due to the strategies implemented to carry out the development of a correct teaching by virtual means, a methodological strategy of experimental tests was developed for the identification of polymeric materials through the identification of physical and chemical properties, with the objective of providing the engineering student a greater approach to the application of the scientific method and the activation of the capacity of reasoning and deductive thinking from the physical and chemical point of view. Therefore, the purpose of this research was to validate this strategy implemented with a group of engineering students, for this purpose, the strategy was implemented, and the results obtained by the students from the development of the experimentation were analyzed, the data were analyzed by means of nonparametric tests, in this case binomial test. Finally, it is concluded that the polymer identification test is feasible to be implemented as a remote laboratory, as a methodical strategy in teaching, since it allows the development of experimentation, in this case, the identification of polymeric materials, which present diverse physical properties.

Multifunctional Molecular and Polymeric Materials for Nonlinear Optics and Photonics

1989 ◽  
Vol 175 ◽  
Author(s):  
Paras N. Prasad
Keyword(s):  
Research Program ◽  
New Technology ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Physical And Chemical Properties ◽  
Multifunctional Materials ◽  
Polymeric Systems ◽  
Natural Systems ◽  
Physical And Chemical ◽  
And Chemical Properties

Molecular units in natural systems are multifunctional in that they exhibit more than one functionalities. This is nature's way of economizing and being efficient. For many technological applications, there is a need for synthetic multifunctional materials which simultaneously exhibit many necessary physical and chemical properties. By appropriate modification of structures both at the molecular and bulk levels, one can incorporate such multifunctionality in molecular and polymeric systems. Our research program focuses on investigations of multifunctional materials for applications in photonics. Photonics describes the emerging new technology in which a photon instead of an electron is used to acquire, process, store and transmit information.

scholarly journals Dendrimers: properties and applications.

2001 ◽  
Vol 48 (1) ◽  
pp. 199-208 ◽  
Author(s):  
B Klajnert ◽  
M Bryszewska
Keyword(s):  
Chemical Properties ◽  
Polymeric Materials ◽  
Industrial Applications ◽  
New Class ◽  
Research Technology ◽  
Concise Review ◽  
Physico Chemical ◽  
Wide Range ◽  
Physical And Chemical ◽  
And Chemical Properties

Dendrimers are a new class of polymeric materials. They are highly branched, monodisperse macromolecules. The structure of these materials has a great impact on their physical and chemical properties. As a result of their unique behaviour dendrimers are suitable for a wide range of biomedical and industrial applications. The paper gives a concise review of dendrimers' physico-chemical properties and their possible use in various areas of research, technology and treatment.

Formation and Characterization of Co-Continuous Shear Thickening Fluid/Polymer Blends

2013 ◽  
Author(s):  
Yifeng Hong ◽  
Donggang Yao
Keyword(s):  
Raw Materials ◽  
Chemical Properties ◽  
Shear Thickening ◽  
Polymeric Materials ◽  
Processing Technique ◽  
Melt Processing ◽  
Neat Polymer ◽  
Shear Thickening Fluid ◽  
Continuous Shear ◽  
Physical And Chemical

By synergistically combining distinct physical and chemical properties of different components, co-continuous polymer blending has become an important route to improve the performance of polymeric materials. Shear thickening fluid is a type of non-Newtonian fluid which has unique shear rate dependence and good damping properties. In this work, the authors combined the shear thickening fluid and a commodity polymer into a single system by forming a co-continuous blend via a melt processing technique. The processing window of such co-continuous blend was determined by referring to the thermal and rheological properties of raw materials and experimentally exploring various blending conditions. An increase of tanδ under dynamic mechanical analyzing testing was observed in the co-continuous blend compared with neat polymer as control, which indicated the enhancement of damping capabilities.

scholarly journals The measure of irregularities of nanosheets

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 419-431
Author(s):  
Zahid Iqbal ◽  
Muhammad Ishaq ◽  
Adnan Aslam ◽  
Muhammad Aamir ◽  
Wei Gao
Keyword(s):  
Statistical Approach ◽  
Chemical Properties ◽  
Polymeric Materials ◽  
Topological Descriptors ◽  
Quantitative Structure ◽  
Structure Property ◽  
Quantitative Characterization ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractNanosheets are two-dimensional polymeric materials, which are among the most active areas of investigation of chemistry and physics. Many diverse physicochemical properties of compounds are closely related to their underlying molecular topological descriptors. Thus, topological indices are fascinating beginning points to any statistical approach for attaining quantitative structure–activity (QSAR) and quantitative structure–property (QSPR) relationship studies. Irregularity measures are generally used for quantitative characterization of the topological structure of non-regular graphs. In various applications and problems in material engineering and chemistry, it is valuable to be well-informed of the irregularity of a molecular structure. Furthermore, the estimation of the irregularity of graphs is helpful for not only QSAR/QSPR studies but also different physical and chemical properties, including boiling and melting points, enthalpy of vaporization, entropy, toxicity, and resistance. In this article, we compute the irregularity measures of graphene nanosheet, H-naphtalenic nanosheet, {\text{SiO}}_{2} nanosheet, and the nanosheet covered by {C}_{3} and {C}_{6}.

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