The Mills–Nixon effect and chemical reactivity—methyl cation affinity of some cycloalkabenzenes

2001 ◽  
pp. 1091-1098 ◽  
Author(s):  
Mirjana Eckert-Maksić ◽  
Zoran Glasovac ◽  
Nana Novak Coumbassa ◽  
Zvonimir B. Maksić
Keyword(s):  
Chemical Reactivity ◽  
Cation Affinity ◽  
Methyl Cation

Methyl Cation Affinity vs Proton Affinity in Substituted Benzenes:  An ab Initio Study

1998 ◽  
Vol 102 (17) ◽  
pp. 2981-2987 ◽  
Author(s):  
Zvonimir B. Maksić ◽  
Mirjana Eckert-Maksić ◽  
Andrea Knežević
Keyword(s):  
Ab Initio ◽  
Proton Affinity ◽  
Ab Initio Study ◽  
Substituted Benzenes ◽  
Cation Affinity ◽  
Methyl Cation

New Theoretical and Experimental Proton Affinities for Methyl Halides and Diazomethane: A Revision of the Methyl Cation Affinity Scale

1994 ◽  
Vol 98 (50) ◽  
pp. 13099-13101 ◽  
Author(s):  
Mikhail N. Glukhovtsev ◽  
Jan E. Szulejko ◽  
T. B. McMahon ◽  
James W. Gauld ◽  
Anthony P. Scott ◽  
...  
Keyword(s):  
Proton Affinities ◽  
Methyl Halides ◽  
Cation Affinity ◽  
Methyl Cation

Methyl cation affinity (MCA) values for phosphanes

2010 ◽  
Vol 23 (11) ◽  
pp. 1036-1042 ◽  
Author(s):  
Christoph Lindner ◽  
Boris Maryasin ◽  
Frank Richter ◽  
Hendrik Zipse
Keyword(s):  
Cation Affinity ◽  
Methyl Cation

Spatially Resolved Photoelectron Spectroscopy: Recent Progress and Future Plans

1990 ◽  
Vol 48 (2) ◽  
pp. 388-389
Author(s):  
A. M. Bradshaw
Keyword(s):  
Photoelectron Spectroscopy ◽  
Chemical Reactivity ◽  
Target Material ◽  
Orbital Energy ◽  
Light Sources ◽  
Analytical Technique ◽  
Hartree Fock ◽  
Spatially Resolved ◽  
Koopmans Theorem ◽  
Surface Analytical Technique

X-ray photoelectron spectroscopy (XPS or ESCA) was not developed by Siegbahn and co-workers as a surface analytical technique, but rather as a general probe of electronic structure and chemical reactivity. The method is based on the phenomenon of photoionisation: The absorption of monochromatic radiation in the target material (free atoms, molecules, solids or liquids) causes electrons to be injected into the vacuum continuum. Pseudo-monochromatic laboratory light sources (e.g. AlKα) have mostly been used hitherto for this excitation; in recent years synchrotron radiation has become increasingly important. A kinetic energy analysis of the so-called photoelectrons gives rise to a spectrum which consists of a series of lines corresponding to each discrete core and valence level of the system. The measured binding energy, EB, given by EB = hv−EK, where EK is the kineticenergy relative to the vacuum level, may be equated with the orbital energy derived from a Hartree-Fock SCF calculation of the system under consideration (Koopmans theorem).

Cluster analysis for large data sets: applications to individual aerosol particles from the mid-pacific

1992 ◽  
Vol 50 (2) ◽  
pp. 1488-1489
Author(s):  
Thomas W. Shattuck ◽  
James R. Anderson ◽  
Neil W. Tindale ◽  
Peter R. Buseck
Keyword(s):  
Cluster Analysis ◽  
Chemical Reactivity ◽  
Large Data ◽  
Large Data Sets ◽  
Particle Analysis ◽  
Data Sets ◽  
Halogen Chemistry ◽  
Complete Study ◽  
Components Analysis ◽  
Automated Scanning

Individual particle analysis involves the study of tens of thousands of particles using automated scanning electron microscopy and elemental analysis by energy-dispersive, x-ray emission spectroscopy (EDS). EDS produces large data sets that must be analyzed using multi-variate statistical techniques. A complete study uses cluster analysis, discriminant analysis, and factor or principal components analysis (PCA). The three techniques are used in the study of particles sampled during the FeLine cruise to the mid-Pacific ocean in the summer of 1990. The mid-Pacific aerosol provides information on long range particle transport, iron deposition, sea salt ageing, and halogen chemistry.Aerosol particle data sets suffer from a number of difficulties for pattern recognition using cluster analysis. There is a great disparity in the number of observations per cluster and the range of the variables in each cluster. The variables are not normally distributed, they are subject to considerable experimental error, and many values are zero, because of finite detection limits. Many of the clusters show considerable overlap, because of natural variability, agglomeration, and chemical reactivity.

Structure Revision of Protoaculeine B, a Posttranslationally Modified N-Terminal Residue in the Peptide Toxin Aculeine B

2020 ◽  
Author(s):  
Raku Irie ◽  
Kei Miyako ◽  
Satoko Matsunaga ◽  
Ryuichi Sakai ◽  
Masato Oikawa
Keyword(s):  
Mass Spectra ◽  
Chemical Reactivity ◽  
Model Compounds ◽  
Structural Revision ◽  
Structure Revision ◽  
Peptide Toxin ◽  
One Step ◽  
Marine Peptide ◽  
Synthetic Models ◽  
Long Chain

<div>Here, we newly propose the structure of protoaculeine B, an N-terminal moiety of the marine peptide toxin aculeine B, as possessing the cis-disubstituted tetrahydro-beta-carboline framework. We prepared two truncated model compounds that lack long-chain polyamine by one-step Pictet-Spengler reaction of tryptophan, and compared the NMR and mass spectra and chemical reactivity with those of natural protoaculeine B. The synthetic models reproduced the profiles of the natural product well, which was conclusive for the structural revision.</div>

Sign in / Sign up

Export Citation Format

Share Document