The Br—O bond in halogen oxides — Empirical force constants and electronic characteristics

2004 ◽  
Vol 82 (6) ◽  
pp. 998-1005
Author(s):  
Rafael Escribano ◽  
Ismael K Ortega ◽  
Rafael G Mosteo ◽  
Pedro C Gómez
Keyword(s):  
Spectroscopic Data ◽  
Force Constants ◽  
Basis Set ◽  
Empirical Determination ◽  
Spectroscopic Information ◽  
Topological Characteristics ◽  
Different Characteristics ◽  
Halogen Oxides ◽  
Systematic Framework

A number of bromine oxides and mixed chlorine–bromine oxides for which spectroscopic information is available have been chosen to investigate the nature and characteristics of the Br—O bond. The study consists of the empirical determination of stretching force constants for these bonds from observed vibrational spectroscopic data and the analysis of the topological characteristics of the bonds via ab initio calculations. The latter have been performed at the MP2 level with a 6-311+G(2df) basis set, to provide a uniform and systematic framework for comparing these species. Three types of Br—O bonds have been found, with different characteristics of strength and electron density. The results are compared with those recently found for the Cl—O bond in chlorine oxides.Key words: bromine oxides, bond electronic structure.

Empirical Determination of the Harmonic Force Constants in Benzene. 4. The Fermi Resonances

2006 ◽  
Vol 110 (51) ◽  
pp. 13769-13774 ◽  
Author(s):  
Svetoslav Rashev ◽  
David C. Moule ◽  
Svetlana T. Djambova
Keyword(s):  
Force Constants ◽  
Harmonic Force ◽  
Empirical Determination ◽  
Fermi Resonances

scholarly journals Extension of an extraction method for the determination of 305 organic compounds in clay-loam soil to soils of different characteristics

MethodsX ◽  
2021 ◽  
pp. 101476
Author(s):  
Andrea Acosta-Dacal ◽  
Cristian Rial-Berriel ◽  
Ricardo Díaz-Día ◽  
María del Mar Bernal-Suárez ◽  
Manuel Zumbado ◽  
...  
Keyword(s):  
Organic Compounds ◽  
Extraction Method ◽  
Clay Loam ◽  
Clay Loam Soil ◽  
Loam Soil ◽  
Different Characteristics

Isolation and Structure Determination of a Heat Shock Protein Inducer, Asparagus-Derived Proline-Containing 3-Alkyldiketopiperazines (Asparaprolines), From a Standardized Extract of Asparagus officinalis Stem

2020 ◽  
Vol 15 (3) ◽  
pp. 1934578X2091468
Author(s):  
Shoichiro Inoue ◽  
Jun Takanari ◽  
Keima Abe ◽  
Ayako Nagayama ◽  
Yukinobu Ikeya ◽  
...  
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Spectroscopic Data ◽  
Asparagus Officinalis ◽  
Hsp70 Mrna ◽  
Mrna Induction ◽  
Natural Amino Acids ◽  
First Time ◽  
Hsp70 Induction

ETAS® has been developed from the stems of Asparagus officinalis L. as a functional ingredient for nutraceuticals. ETAS possesses heat shock protein 70 (HSP70) induction activity and may contribute to maintenance and improvement of health. Here, 3 compounds (1, 2, 3) were isolated from ETAS. The structures of 1, 2, and 3 were deduced by HREIMS and NMR spectroscopic data, and the compounds were identified as cyclo(l-Phe-l-Pro), cyclo(l-Tyr-l-Pro), and cyclo(l-Leu-l-Pro), respectively. Each compound contained a diketopiperazine ring derived from proline with an alkyl group at C-3; thus, we termed them asparagus-derived proline-containing 3-alkyldiketopiperazines (Asparaprolines). In an HSP70 mRNA induction assay in HL-60 cells, Asparaprolines significantly enhanced the expression of HSP70 mRNA compared with a control. To our knowledge, these results demonstrate for the first time that proline-containing diketopiperazines derived from natural amino acids exhibit HSP70 mRNA induction activity.

The determination of force constants from isotopic frequencies using parameter representation

1973 ◽  
Vol 16 (1) ◽  
pp. 149-157 ◽  
Author(s):  
T.R. Ananthakrishnan ◽  
C.P. Girijavallabhan ◽  
G. Aruldhas
Keyword(s):  
Force Constants ◽  
Parameter Representation
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