Controllable spontaneous resolution in ultrasmall Cu-Ag bimetallic cluster ion pairs from achiral components

2022 ◽  
Author(s):  
Jiao He ◽  
chenglong deng ◽  
Cunfa Sun ◽  
Xiao-Xiao Zhang ◽  
Ying Cui ◽  
...  
Keyword(s):  
Ion Pairs ◽  
Spontaneous Resolution ◽  
Bimetallic Cluster ◽  
Cluster Ion ◽  
Anionic Cluster

Bimetallic cluster ion pairs containing a quaternary phosphonium and an ultrasmall Cu2Ag3 anionic cluster protected by thiolates: (PPh3R″)[Cu2Ag3(SR′)6] (R′SH = cyclohexylthiol (CySH), R″ = Ph, 1; Me, 2; Et, 3;...

scholarly journals Exploring the chemical fate of the sulfate radical anion by reaction with sulfur dioxide in the gas phase

2014 ◽  
Vol 14 (9) ◽  
pp. 12863-12886
Author(s):  
N. T. Tsona ◽  
N. Bork ◽  
H. Vehkamäki
Keyword(s):  
Relative Humidity ◽  
Gas Phase ◽  
Reaction Rate ◽  
Reaction Rate Constant ◽  
Phase Reaction ◽  
So2 Oxidation ◽  
Gas Phase Reaction ◽  
Cluster Ion ◽  
Anionic Cluster ◽  
Sulfate Radical Anion

Abstract. The gas phase reaction between SO4−(H2O)n and SO2, n = 0–2, is investigated using ab initio calculations and kinetic modeling. Structures of reactants, transition states and products are reported. Our calculations predict that the SO2SO4−(H2O)n cluster ion, formed upon SO2 and SO4−(H2O)n collision, can isomerize to SO3SO3−(H2O)n. The overall reaction is SO2 oxidation by the SO4−(H2O)n anionic cluster. The results show that SO4−(H2O)n is a good SO2 oxidant, especially at low relative humidity, with a~reaction rate constant up to 1.1 × 10−10 cm3 molecule−1 s−1. At high relative humidity, instead, the re-evaporation of SO2 from the SO2SO4−(H2O)n cluster ion is favoured.

scholarly journals Exploring the chemical fate of the sulfate radical anion by reaction with sulfur dioxide in the gas phase

2015 ◽  
Vol 15 (1) ◽  
pp. 495-503 ◽  
Author(s):  
N. T. Tsona ◽  
N. Bork ◽  
H. Vehkamäki
Keyword(s):  
Relative Humidity ◽  
Gas Phase ◽  
Reaction Rate ◽  
Kinetic Modelling ◽  
Reaction Rate Constant ◽  
Phase Reaction ◽  
So2 Oxidation ◽  
Cluster Ion ◽  
Anionic Cluster ◽  
Sulfate Radical Anion

Abstract. The gas phase reaction between SO4−(H2O)n and SO2, n = 0–2, is investigated using ab initio calculations and kinetic modelling. Structures of reactants, transition states and products are reported. Our calculations predict that the SO2SO4−(H2O)n cluster ion, which is formed upon SO2 and SO4−(H2O)n collision, can isomerize to SO3SO3−(H2O)n. The overall reaction is SO2 oxidation by the SO4−(H2O)n anionic cluster. The results show that SO4−(H2O)n is a good SO2 oxidant, especially at low relative humidity, with a reaction rate constant up to 1.5 × 10−10 cm3 molecule−1s−1. At high relative humidity, instead, the re-evaporation of SO2 from the SO2SO

Chemistry of gaseous ion pairs produced by thermal collisions

1980 ◽  
Vol 77 ◽  
pp. 759-768 ◽  
Author(s):  
R. Stephen Berry
Keyword(s):  
Ion Pairs

A Case of Spontaneous Resolution of Castleman's Disease in the Neck

2012 ◽  
Vol 55 (11) ◽  
pp. 736
Author(s):  
Seong-Hyun Yun ◽  
Soo-Ryang Chae ◽  
Dong-Joon Yoo ◽  
Young-Hoon Joo
Keyword(s):  
Castleman’S Disease ◽  
Spontaneous Resolution ◽  
Castleman's Disease

Spontaneous resolution of hypothalamic amenorrhea post diagnostic GnRH test

2015 ◽  
Author(s):  
G K Dimitriadis ◽  
M O Weickert ◽  
T M Barber ◽  
H S Randeva
Keyword(s):  
Spontaneous Resolution ◽  
Hypothalamic Amenorrhea

Ion Pairing and Dielectric Decrement in Glycosaminoglycan Brushes

2020 ◽  
Author(s):  
James Sterling ◽  
Wenjuan Jiang ◽  
Wesley M. Botello-Smith ◽  
Yun L. Luo
Keyword(s):  
Molecular Dynamics ◽  
Ion Pairs ◽  
Mean Field ◽  
Salt Bridge ◽  
Ion Pairing ◽  
Donnan Potential ◽  
Mean Field Models ◽  
Ion Exclusion ◽  
Dynamics Simulations ◽  
Contact Ion Pairs

Molecular dynamics simulations of hyaluronic acid and heparin brushes are presented that show important effects of ion-pairing, water dielectric decrease, and co-ion exclusion. Results show equilibria with electroneutrality attained through screening and pairing of brush anionic charges by cations. Most surprising is the reversal of the Donnan potential that would be expected based on electrostatic Boltzmann partitioning alone. Water dielectric decrement within the brush domain is also associated with Born hydration-driven cation exclusion from the brush. We observe that the primary partition energy attracting cations to attain brush electroneutrality is the ion-pairing or salt-bridge energy associated with cation-sulfate and cation-carboxylate solvent-separated and contact ion pairs. Potassium and sodium pairing to glycosaminoglycan carboxylates and sulfates consistently show similar abundance of contact-pairing and solvent-separated pairing. In these crowded macromolecular brushes, ion-pairing, Born-hydration, and electrostatic potential energies all contribute to attain electroneutrality and should therefore contribute in mean-field models to accurately represent brush electrostatics.

Stereospecific 1,3-H Transfer of Indenols Proceeds via Persistent Ion-Pairs Anchored By NH···Pi Interactions

2018 ◽  
Author(s):  
David Ascough ◽  
Fernanda Duarte ◽  
Robert Paton
Keyword(s):  
Computational Analysis ◽  
Ion Pairs ◽  
Ion Pair ◽  
Hydrogen Atom Transfer ◽  
Polar Solvents ◽  
Chirality Transfer ◽  
Activation Barriers ◽  
Sense And Avoid ◽  
Phase Dynamics ◽  
Pi Interactions

The base-catalyzed rearrangement of arylindenols is a rare example of a suprafacial [1,3]-hydrogen atom transfer. The mechanism has been proposed to proceed via sequential [1,5]-sigmatropic shifts, which occur in a selective sense and avoid an achiral intermediate. A computational analysis using quantum chemistry casts serious doubt on these suggestions: these pathways have enormous activation barriers and in constrast to what is observed experimentally, they overwhelmingly favor a racemic product. Instead we propose that a suprafacial [1,3]-prototopic shift occurs in a two-step deprotonation/reprotonation sequence. This mechanism is favored by 15 kcal mol<sup>-1</sup> over that previously proposed. Most importantly, this is also consistent with stereospecificity since reprotonation occurs rapidly on the same p-face. We have used explicitly-solvated molecular dynamics studies to study the persistence and condensed-phase dynamics of the intermediate ion-pair formed in this reaction. Chirality transfer is the result of a particularly resilient contact ion-pair, held together by electrostatic attraction and a critical NH···p interaction which ensures that this species has an appreciable lifetime even in polar solvents such as DMSO and MeOH.

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