High Pressure Raman Study of the Hydrolysis Reaction of Tmos and Teos

1990 ◽  
Vol 180 ◽  
Author(s):  
G. Hoang ◽  
J. Watson ◽  
T. W. Zerda
Keyword(s):  
Raman Spectroscopy ◽  
Dielectric Constant ◽  
High Pressure ◽  
Hydrogen Bonding ◽  
Raman Band ◽  
Dipole Moments ◽  
Hydrolysis Reaction ◽  
Or Groups ◽  
Bonding Properties ◽  
Raman Study

ABSTRACTHigh pressure Raman spectroscopy is used to monitor the hydrolysis reaction of TMOS in solutions with methanol, acetonitrile, acetone, dioxane and formamide, and of TEOS as a function of pH and the catalyst used. The rate constants for various solvents, temperatures and pressures are experimentally determined from the time dependence of Raman band intensities. It is shown that the reaction is slow in dioxane and fast in methanol or formamide. The volume of activation is found from the pressure dependence of the rate constant. The volume of activation, the dielectric constant, dipole moments and hydrogen bonding properties and their role in the hydrolysis reaction are discussed. It is shown that solvents which can form hydrogen bonding with Si-OR groups can increase the rate of the reaction.

Conformation and Hydrogen Bonding Properties of an Aziridinyl Peptide:  X-ray Structure Analysis, Raman Spectroscopy and Theoretical Investigations

2004 ◽  
Vol 108 (51) ◽  
pp. 11398-11408 ◽  
Author(s):  
Tanja Schirmeister ◽  
Alexander Breuning ◽  
Alexander Murso ◽  
Dietmar Stalke ◽  
Milena Mladenovic ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Hydrogen Bonding ◽  
Structure Analysis ◽  
X Ray ◽  
Theoretical Investigations ◽  
Bonding Properties

Intermolecular Hydrogen Bonding and Structures in 1,3-Dioxane/D2O Mixtures Studied by High-Pressure Raman Spectroscopy

2005 ◽  
Vol 52 (4) ◽  
pp. 625-630
Author(s):  
Jui-San Lin ◽  
Jyh-Chiang Jiang ◽  
Chih-Min Chang ◽  
Wen-Wei Lai ◽  
Jing-Wen Fang ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Hydrogen Bonding ◽  
Intermolecular Hydrogen Bonding

High-pressure Raman study of the alkaline-earth metal fulleride, Ca2.75C60

2020 ◽  
Vol 34 (19n20) ◽  
pp. 2040056 ◽  
Author(s):  
A. G. V. Terzidou ◽  
T. Nakagawa ◽  
N. Yoshikane ◽  
R. Rountou ◽  
J. Rix ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Rare Earth ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Reduced Pressure ◽  
Pressure Coefficients ◽  
Raman Study ◽  
Orbital Mixing

The structural stability and electronic properties of [Formula: see text] are probed by means of high-pressure Raman spectroscopy using two different pressure transmitting media that lead to practically identical results. Although [Formula: see text] is isostructural with the rare-earth metal fulleride, [Formula: see text] of the same stoichiometry, the pressure coefficients of characteristic intramolecular [Formula: see text] modes are larger than those in the [Formula: see text] counterpart but similar to those in the pristine [Formula: see text] solid. Since the reduced pressure coefficients in the Sm fulleride have been attributed to strong [Formula: see text] coupling, our findings for the isostructural Ca fulleride are compatible with a reduced orbital mixing and [Formula: see text] coupling.

Study of the protonation of simple Schiff bases in solvents of various polarity by means of Raman spectroscopy

1991 ◽  
Vol 69 (2) ◽  
pp. 239-245 ◽  
Author(s):  
S. Alex ◽  
P. Turcotte ◽  
R. Fournier ◽  
D. Vocelle
Keyword(s):  
Amino Acids ◽  
Raman Spectroscopy ◽  
Hydrogen Bonding ◽  
Schiff Base ◽  
Organic Acids ◽  
Schiff Bases ◽  
Spectral Response ◽  
The Other ◽  
Intensity Measurements ◽  
Bonding Properties

In this study, the protonation of simple Schiff bases by organic acids in various solvents is investigated by Raman spectroscopy and the spectral response of the C=N+ stretching mode is correlated with the macroscopic properties of the medium surrounding the imine. Upon protonation, the unperturbed C=N stretch increases in frequency due to the combination of the coupling with the C=N+H bend and a partial rehybridization of the C=N bond. Depending on the proton location relative to that of its counterion, one mechanism may prevail over the other. Intensity measurements show that protonation is mostly controlled by the hydrogen bonding properties of the solvent and by the polarity of the medium. However, whatever the solvent, full proton transfer cannot be achieved with organic acids with pKa similar to the COOH of amino acids found in visual or bacterial pigments, meaning that the protonation mechanism may depend upon particular properties of the protein. Key words: imines, protonation, Raman spectroscopy, rhodopsin, Schiff base.

Hydrogen bonding in liquid methanol at ambient conditions and at high pressure

2000 ◽  
Vol 98 (3) ◽  
pp. 125-134 ◽  
Author(s):  
T. Weitkamp, J. Neuefeind, H. E. Fisch
Keyword(s):  
High Pressure ◽  
Hydrogen Bonding ◽  
Ambient Conditions

High-Pressure Raman Study of Liquid and Crystalline CH2F2up to 29 GPa

1994 ◽  
Vol 63 (3) ◽  
pp. 934-940 ◽  
Author(s):  
Wu Youhong ◽  
Mitsukazu Onomichi ◽  
Shigeo Sasaki ◽  
Hiroyasu Shimizu
Keyword(s):  
High Pressure ◽  
Raman Study

Raman spectroscopy on single- and multi-walled nanotubes under high pressure

1999 ◽  
Vol 69 (3) ◽  
pp. 309-312 ◽  
Author(s):  
C. Thomsen ◽  
S. Reich ◽  
H. Jantoljak ◽  
I. Loa ◽  
K. Syassen ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure

High-pressure structural phase transition and metallization in Ga2S3 under non-hydrostatic and hydrostatic conditions up to 36.4 GPa

2021 ◽  
Author(s):  
Linfei Yang ◽  
Jianjun Jiang ◽  
Lidong Dai ◽  
Haiying Hu ◽  
Meiling Hong ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
High Pressure ◽  
Structural Properties ◽  
Structural Phase Transition ◽  
First Principles ◽  
Theoretical Calculations ◽  
Structural Phase

The vibrational, electrical and structural properties of Ga2S3 were explored by Raman spectroscopy, EC measurements, HRTEM and First-principles theoretical calculations under different pressure environments up to 36.4 GPa.

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