Anion–π interactions and positive electrostatic potentials of N-heterocycles arise from the positions of the nuclei, not changes in the π-electron distribution

2014 ◽  
Vol 50 (76) ◽  
pp. 11118-11121 ◽  
Author(s):  
Steven E. Wheeler ◽  
Jacob W. G. Bloom
Keyword(s):  
Electron Density ◽  
Electron Distribution ◽  
Electrostatic Potentials ◽  
Anion Binding ◽  
Π Interactions

The positive ESPs that underlie anion-binding by N-heterocycles do not stem from a depletion of π-electron density, as widely assumed.

Cambiarenes: Single-Step Synthesis and Anion Binding of a Clip- Shaped Macrocycle with a Redox-Active Core

2019 ◽  
Author(s):  
Riley J. Petersen ◽  
Brett J. Rozeboom ◽  
Shalisa Oburn ◽  
Nolan Blythe ◽  
Tanner Rathje ◽  
...  
Keyword(s):  
Electron Density ◽  
Single Step ◽  
Anion Binding ◽  
Host Molecule ◽  
Selective Binding ◽  
The Core ◽  
Redox Active ◽  
Active Core ◽  
Guest Binding

<div>We report the synthesis of a novel macrocyclic host molecule that forms in a single step from commercially available starting materials. The core of the macrocycle backbone possesses two quinone rings and, thus, is redox-active. Host-guest binding involving the clip-shaped cavity indicates selective binding of pyridine <i>N</i>-oxides based of the electron density of and steric bulk of the anionic oxygen.</div>

scholarly journals Die zeitliche Änderung der radialen Elektronendichteverteilung beim Theta-Pinch

1963 ◽  
Vol 18 (8-9) ◽  
pp. 895-900
Author(s):  
Franz Peter Küpper
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Electron Distribution ◽  
Radial Symmetry ◽  
Zero Order ◽  
Time Interval ◽  
Interferometric Method ◽  
Density Distributions ◽  
Theta Pinch

In a θ-pinch the radial symmetry of the electron density distribution as a function of time has been measured by a MACH—ZEHNDER interferometer. In a time interval of 400 nsec during a discharge an image converter made three pictures (exposure times of 10 nsec each) . Up to 100 nsec after the first compression, the experimental results show different density distributions for the cases of trapped parallel and antiparallel magnetic fields. Complete radial symmetry of the electron density distribution was not found.Another interferometric method for measuring the radial symmetry of the electron distribution by observing “zero order” fringes is described.

scholarly journals The Galactic Electron Distribution from a Pulsar Survey

1974 ◽  
Vol 60 ◽  
pp. 87-95 ◽  
Author(s):  
A. G. Lyne
Keyword(s):  
Electron Density ◽  
Electron Distribution ◽  
Statistical Study ◽  
High Sensitivity ◽  
Upper Limit ◽  
The Mean

The recent high-sensitivity pulsar survey at Jodrell Bank has allowed a statistical study of more distant objects. The longitude distribution suggests that many of the pulsars observed have distances greater than 5 kpc, leading to an upper limit of about 0.03 cm-3 for the mean electron density. The electron density averaged over distances of a few hundred parsecs seems to be very constant. The width of the electron distribution in the z-direction appears to be greater than about 600 pc.

The ' Variable Electronegativity ' Method. III. The Pyrrole Anion and Electronegativity Reversal

1959 ◽  
Vol 12 (3) ◽  
pp. 330 ◽  
Author(s):  
RD Brown ◽  
ML Heffernan
Keyword(s):  
Electron Density ◽  
Electron Distribution ◽  
Ionization Potentials ◽  
Alternative Methods ◽  
Electron Densities ◽  
Tertiary Nitrogen

The π-electron distribution in the pyrrole anion has been evaluated by the VESCF method using two alternative methods of estimating core attraction terms. The results indicate that the π-electron distribution around the conjugated system is very nearly uniform, supporting previous speculations that the relative attracting powers of tertiary nitrogen and carbon reverse when their π-electron densities exceed a certain value, suspected to be not too much greater than unity. The present calculations indicate that the critical π-electron density is around 1.2. The VESCF estimates of ionization potentials of the pyrrole anion are also reported.

Organometallic cavitands: Cation–π interactions and anion binding via π-metallation

2007 ◽  
Vol 251 (13-14) ◽  
pp. 1747-1760 ◽  
Author(s):  
Joseph T. Lenthall ◽  
Jonathan W. Steed
Keyword(s):  
Anion Binding ◽  
Π Interactions

Scattering from magnetic fluctuationst†

1971 ◽  
Vol 5 (2) ◽  
pp. 225-228 ◽  
Author(s):  
William B. Thompson
Keyword(s):  
Electron Density ◽  
Electron Distribution ◽  
Electron Distribution Function ◽  
Density Fluctuations ◽  
Mass Ratio ◽  
Radio Frequency Radiation ◽  
Scattered Spectrum ◽  
Electron Density Fluctuations ◽  
The Magnetic Field ◽  
Frequency Radiation

Scattering of optical and radio frequency radiation from electron density fluctuations in a plasma has been extensively studied and bids fair to become a useful diagnostic tool (see, for example, Davies & Ramsden, 1964, 1966). The scattered spectrum, although difficult to observe, contains a great deal of information. The electron density, ion and electron temperatures, the shape of the tail of the electron distribution function, spectral fluctuations in unstable systems, the magnitude and direction of the magnetic field and the charge to mass ratio of the ions present all seem to be contained in it.

Elektronenkorrelationseffekte in der Elektronendichteverteilung von Stickstoff und Acetylen / Effects of Electron Correlation in the Electron Density Distribution of Nitrogen and Acetylene

1978 ◽  
Vol 33 (2) ◽  
pp. 245-246
Author(s):  
Hans-Lothar Hase ◽  
Karl-Wilhelm Schulte ◽  
Armin Schweig
Keyword(s):  
Density Distribution ◽  
Electron Density ◽  
Electron Correlation ◽  
Electron Density Distribution ◽  
Electron Distribution ◽  
Lone Pair ◽  
General Interest ◽  
Atomic Core ◽  
Difference Density ◽  
Ci Calculations

It is shown by AHF-CI calculations that the changes in the electron distribution in bonding and lone pair regions of nitrogen and acetylene due to electron correlation can be neglected when calculating electron difference densities of these molecules. The changes brought about by electron correlation are such that the electron density in interatomic regions is reduced and in atomic (core) regions increased. These results might meet general interest in the area of electron difference density determinations.

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