scholarly journals Selectivity of weak intermolecular forces and precursor state of elementary oxidation reactions, a new insight on Ne* + N2 chemiionization

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stefano Falcinelli ◽  
Franco Vecchiocattivi ◽  
Fernando Pirani
Keyword(s):  
Open Shell ◽  
Intermolecular Forces ◽  
Collision Dynamics ◽  
Oxidation Reactions ◽  
Molecular Beam Scattering ◽  
Fundamental Interest ◽  
Precursor State ◽  
New Formulation ◽  
Weak Intermolecular Forces

AbstractThis paper reports on the collision dynamics of N2 with metastable Ne* promoting chemiionizations, prototype of barrier-less oxidation reactions of great interest for fundamental and applied research. Extending guidelines presented in previous papers for the atom–atom case, an innovative treatment of the reaction stereodynamics involving molecules in a quantum state-to-state resolution conditions is proposed that emphasizes the role of structure and stability of the precursor that is here the reaction transition state. A critical test of such treatment, carried out exploiting a new formulation both of real and imaginary parts of the optical potential driving the reaction dynamics, is represented by the detailed-combined description of all relevant findings, provided by high resolution molecular beam scattering experiments carried out in our and other laboratories. The present analysis casts light on basic electronic rearrangements of such prototype oxidation reaction which are expected to be of fundamental interest for many other reactions involving open shell atoms and free radicals.

Weak Intermolecular Forces, but High Melting Points

2017 ◽  
Vol 70 (5) ◽  
pp. 538 ◽  
Author(s):  
Jiabin Gao ◽  
Djamal Djaidi ◽  
Christopher E. Marjo ◽  
Mohan M. Bhadbhade ◽  
Alison T. Ung ◽  
...  
Keyword(s):  
Molar Mass ◽  
Intermolecular Forces ◽  
High Melting ◽  
High Melting Point ◽  
Enantiomerically Pure ◽  
X Ray ◽  
Drug Molecules ◽  
Poorly Soluble ◽  
Weak Intermolecular Forces

The poorly soluble racemic compound 6,6a,13,13a-tetrahydropentaleno[1,2-b:4,5-b′]diquinoline (4) has an exceptionally high melting point range of 352–354°C despite its low molar mass (308.38) and a structure containing only 40 atoms (38 of which are C and H). Analysis of the X-ray crystal structure and Hirshfeld surface of 4, along with comparison with its isostructural homologue 2, reveals how this occurs in the absence of Pauling-type hydrogen bonding. Excellent complementarity between homochiral molecules of 4 allows formation of enantiomerically pure layers using C–H⋯π, aromatic π⋯π, and C–H⋯N interactions. The alternating layers of opposite handedness are then crosslinked by means of aza-1,3-peri hydrogen interactions. This bifurcated C–H⋯N⋯H–C motif acts as a molecular clip creating a highly rigid network structure. The role of weaker intermolecular forces in influencing the solubility and bioavailability of potential drug molecules is discussed in the context of the popular Lipinski ‘rule of 5’ guidelines.

scholarly journals Precursor state of chemi-ionization reactions and confinement of valence electrons by anisotropic intermolecular forces

2021 ◽  
Vol 75 (3) ◽  
Author(s):  
Stefano Falcinelli ◽  
Franco Vecchiocattivi ◽  
Simonetta Cavalli ◽  
Fernando Pirani
Keyword(s):  
Noble Gas ◽  
Intermolecular Forces ◽  
Basic Step ◽  
Precursor State ◽  
Quantum Confinement Effects ◽  
General Relevance ◽  
Valence Electrons ◽  
Great Relevance ◽  
Experimental Findings

Abstract Modifications in atomic alignment and in molecular alignment/orientation determine a different structure of the adduct, formed by collisions of reagents, which represents the precursor state of many elementary chemical–physical processes. The following evolution of the system is directly controlled by the confinement of interacting partners in such a precursor state. However, a deep characterization of these phenomena is still today not fully available, especially when weak intermolecular forces are operative, although the inquiry is of general relevance for the control of the stereodynamics of processes, occurring under a variety of conditions both in gas phase and at surface. In this paper recent advances in the knowledge of the selective role of atomic alignment and molecular orientation effects on the stereodynamics of chemi-ionization reactions will be presented and discussed. These advances represent a basic step along a path whose final target is the complete and internally consistent rationalization and revaluation of the experimental findings already obtained, and published, in our and in other laboratories on chemi-ionization reactions involving as reagent molecules which are of great relevance in several fields. The basic idea is to export important guidelines provided by a recent detailed study of chemi-ionization of noble gas atoms to more complex reactions involving molecules. The main focus of the present paper is on the quantum confinement effects of valence electrons within the reaction transition state. Graphic abstract

scholarly journals Influence of the Electrolyte Salt Concentration on DNA Detection with Graphene Transistors

Biosensors ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 24
Author(s):  
Agnes Purwidyantri ◽  
Telma Domingues ◽  
Jérôme Borme ◽  
Joana Rafaela Guerreiro ◽  
Andrey Ipatov ◽  
...  
Keyword(s):  
Phosphate Buffer ◽  
Species Interactions ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Limit Of Detection ◽  
Debye Length ◽  
Intermolecular Forces ◽  
Single Layer Graphene ◽  
Dna Adsorption

Liquid-gated Graphene Field-Effect Transistors (GFET) are ultrasensitive bio-detection platforms carrying out the graphene’s exceptional intrinsic functionalities. Buffer and dilution factor are prevalent strategies towards the optimum performance of the GFETs. However, beyond the Debye length (λD), the role of the graphene-electrolytes’ ionic species interactions on the DNA behavior at the nanoscale interface is complicated. We studied the characteristics of the GFETs under different ionic strength, pH, and electrolyte type, e.g., phosphate buffer (PB), and phosphate buffer saline (PBS), in an automatic portable built-in system. The electrostatic gating and charge transfer phenomena were inferred from the field-effect measurements of the Dirac point position in single-layer graphene (SLG) transistors transfer curves. Results denote that λD is not the main factor governing the effective nanoscale screening environment. We observed that the longer λD was not the determining characteristic for sensitivity increment and limit of detection (LoD) as demonstrated by different types and ionic strengths of measuring buffers. In the DNA hybridization study, our findings show the role of the additional salts present in PBS, as compared to PB, in increasing graphene electron mobility, electrostatic shielding, intermolecular forces and DNA adsorption kinetics leading to an improved sensitivity.

Role of Intermolecular Forces in Defining Material Properties of Protein Nanofibrils

Science ◽  
2007 ◽  
Vol 318 (5858) ◽  
pp. 1900-1903 ◽  
Author(s):  
T. P. Knowles ◽  
A. W. Fitzpatrick ◽  
S. Meehan ◽  
H. R. Mott ◽  
M. Vendruscolo ◽  
...  
Keyword(s):  
Material Properties ◽  
Intermolecular Forces

Proton-induced collision dynamics on potential prebiotic sulfur species

2018 ◽  
Vol 20 (14) ◽  
pp. 9084-9089 ◽  
Author(s):  
Marie-Christine Bacchus-Montabonel
Keyword(s):  
Charge Transfer ◽  
Ab Initio ◽  
Theoretical Study ◽  
Collision Dynamics ◽  
Sulfur Species ◽  
Hcn Oligomers ◽  
Induced Charge

The role of sulfur in proton-induced charge transfer is analyzed through an ab initio theoretical study of mercaptoacetonitrile HSCH2CN with related HCN oligomers.

The Role of Cytochrome P-450 in Microsomal Mixed Function Oxidation Reactions

1968 ◽  
pp. 142-195 ◽  
Author(s):  
R. W. Estabrook ◽  
A. Hildebrandt ◽  
H. Remmer ◽  
J. B. Schenkman ◽  
O. Rosenthal ◽  
...  
Keyword(s):  
Oxidation Reactions ◽  
Cytochrome P 450

4. Gelification and soapiness

2020 ◽  
pp. 63-90
Author(s):  
Tom McLeish
Keyword(s):  
Brownian Motion ◽  
Self Assembly ◽  
Soft Matter ◽  
Intermolecular Forces ◽  
Two Dimensional ◽  
Important Distinction ◽  
One Dimensional ◽  
The Third ◽  
Self Assembled ◽  
Weak Intermolecular Forces

‘Gelification and soapiness’ looks at the third class of soft matter: ‘self-assembly’. Like the colloids of inks and clays, and the polymers of plastics and rubbers, ‘self-assembled’ soft matter also emerges as a surprising consequence of Brownian motion combined with weak intermolecular forces. Like them, it also leads to explanations of a very rich world of materials and phenomena, such as gels, foams, soaps, and ultimately to many of the structures of biological life. There is an important distinction that needs to be made between one-dimensional and two-dimensional self-assembly.

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