What are the Molecules of Which the Samples of Metal Alkoxides do Really Consist ?

1994 ◽  
Vol 346 ◽  
Author(s):  
N.Ya. Turova ◽  
N.I. Kozlova ◽  
E.P. Turevskaya ◽  
T.V. Rogova ◽  
V.G. Kessler
Keyword(s):  
Gas Phase ◽  
Aromatic Hydrocarbons ◽  
Mass Spectra ◽  
Mixed Oxides ◽  
Metal Alkoxides ◽  
Boiling Points ◽  
Thermal Constants ◽  
Molecular Masses ◽  
Molecular Complexity ◽  
The Stability

ABSTRACTOn the basis of consideration of the properties of AI, In, Ln, Ti, Zr, Hf, NbO3+, MoO4+, WO4+, MoO22+ MO22+, Fe, Co, Ni alkoxide derivatives the main regularities in poly- and oligomerization properties have been deduced:1) The molecular complexity increases in time (aging) and on action of alcohols. This process is followed by the increase in the melting and boiling points, decrease in solubility in ROH and weakening of colour. In the mass-spectra - in connection with the temperature of transition into the gas phase - increases the stability of products with lower molecular masses. 2) oligomerization occurs on dissolution in aromatic hydrocarbons or on a short thermal treatment (melting, distillation). The oligomerization products possess lower thermal constants, higher solubility in ROH and more intense colour. Their mass- spectra are containing the fragments of higher masses corresponding to oligomers existing apparently also in the condensed phase.The mastering of these regularities permits the monitoring of molecular composition and thus physicochemical properties of the samples which are of importance for their technological application.The presence of oxoalkoxides in the “M(OR)n” samples should be taken into consideration on the preparation of solutions used in the synthesis of powders and films of pure simple and mixed oxides.

scholarly journals Tracing The Acid-Base Catalytic Properties Of MON2O Mixed Oxides (M=Be, Mg, Ca; N=Li, Na, K) By Theoretical Calculations

2021 ◽  
Author(s):  
Dawid Faron ◽  
Piotr Skurski ◽  
Iwona Anusiewicz
Keyword(s):  
Alkali Metal ◽  
Gas Phase ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Theoretical Calculations ◽  
Lewis Acidity ◽  
Free Energies ◽  
Acid Base ◽  
The Stability ◽  
Fragmentation Processes

Abstract The stability and acid-base properties of MON2O mixed oxides (where M = Be, Mg, Ca; N = Li, Na, K) are studied by using ab initio methods. It is demonstrated that (i) the basicity of such designed systems evaluated by estimation of electronic proton affinity and gas-phase basicity (defined as the electronic and Gibbs free energies of deprotonation processes for [MON2O]H+) were found significant (in the ranges of 272–333 kcal/mol and 260–322 kcal/mol, respectively); (ii) in each series of MOLi2O/MONa2O/MOK2O the basicity increases with an increase of the atomic number of alkali metal involved; (ii) the Lewis-acidity of the corresponding [MON2O]H+ determined with respect to hydride anion (assessed as the electronic and Gibbs free energies of H− detachment processes for [MON2O]H2) decreases as the basicity of the corresponding oxide increases. The thermodynamic stability of all [MON2O]H2 systems is confirmed by estimating the Gibbs free energies for the fragmentation processes yielding either H2 or H2O.

The Generation of Low-Valence Tin Derivatives, RSn(I), in the Gas-Phase by Neutralization—reionization Mass Spectrometry

2002 ◽  
Vol 8 (5) ◽  
pp. 351-357 ◽  
Author(s):  
Dmitri Zagorevskii ◽  
Yang Yuan ◽  
C. Michael Greenlief ◽  
Alexander A. Mommers
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Quantum Chemical Calculations ◽  
Molecular Species ◽  
Quantum Chemical ◽  
Mass Spectra ◽  
Stable Species ◽  
The Stability ◽  
Franck Condon

Neutralization-reionization mass spectrometry (NRMS) was applied to the generation and characterization of low-valence Sn(I) derivatives. The observation of recovery signals in the NR mass spectra of RSn+ ions (R=H, Cl, Br, CH3, C2H, C6H5) demonstrated that their neutral counterparts are stable species in the gas-phase with a lifetime of at least 5 μs. According to quantum chemical calculations, a favorable Franck–Condon factor may contribute to the stability of RSn neutrals generated in the NR event. The experimental results for tin acetylide and phenyltin are the first examples of the generation of these previously unknown molecular species.

scholarly journals Tracing the acid-base catalytic properties of MON2O mixed oxides (M = Be, Mg, Ca; N = Li, Na, K) by theoretical calculations

2021 ◽  
Vol 27 (7) ◽  
Author(s):  
Dawid Faron ◽  
Piotr Skurski ◽  
Iwona Anusiewicz
Keyword(s):  
Gas Phase ◽  
Mixed Oxides ◽  
Catalytic Properties ◽  
Theoretical Calculations ◽  
Lewis Acidity ◽  
Ab Initio Methods ◽  
Free Energies ◽  
Acid Base ◽  
The Stability ◽  
Fragmentation Processes

AbstractThe stability and acid-base properties of MON2O mixed oxides (where M = Be, Mg, Ca; N = Li, Na, K) are studied by using ab initio methods. It is demonstrated that (i) the basicity of such designed systems evaluated by estimation of electronic proton affinity and gas-phase basicity (defined as the electronic and Gibbs free energies of deprotonation processes for [MON2O]H+) were found significant (in the ranges of 272–333 and 260–322 kcal/mol, respectively); (ii) in each series of MOLi2O/MONa2O/MOK2O, the basicity increases with an increase of the atomic number of alkali metal involved; (ii) the Lewis acidity of the corresponding [MON2O]H+ determined with respect to hydride anion (assessed as the electronic and Gibbs free energies of H− detachment processes for [MON2O]H2) decreases as the basicity of the corresponding oxide increases. The thermodynamic stability of all [MON2O]H2 systems is confirmed by estimating the Gibbs free energies for the fragmentation processes yielding either H2 or H2O.

scholarly journals Polyoxymethylene in Cometary Dust: Laboratory Tests

1991 ◽  
Vol 126 ◽  
pp. 265-268
Author(s):  
D.C. Boice ◽  
D.W. Naegeli ◽  
W.F. Huebner
Keyword(s):  
Gas Phase ◽  
Laboratory Tests ◽  
Mass Spectra ◽  
Water Solution ◽  
High Molecular Mass ◽  
Methanol Solution ◽  
Cometary Dust ◽  
Laboratory Results ◽  
End Capping ◽  
The Stability

AbstractWe have investigated the stability of gas-phase formaldehyde oligomers and its implications for cometary science. Our experiments indicate that when a formaldehyde-methanol solution is vaporized in the mass spectrometer, high molecular mass POM species (45, 61, 75, 91, 105, 121, 135, 151, 165 amu) exist in the gas phase in the temperature range 473 K to 773 K. These laboratory results complement our previous experiments using a formaldehyde-water solution and indicate that formaldehyde oligomers are stable in the gas phase up to at least 6 monomeric units in length. Methanol is important in the end-capping process of the oligomers, leading to increased stability and a richer mass spectrum when compared to the formaldehyde-water solution. The results are consistent with mass spectra obtained by theGiottoPICCA instrument exhibiting alternating 14-16 amu mass peaks.

High-Loading Crystals of Tetraaryladamantanes and the Uptake and Release of Aromatic Hydrocarbons from the Gas Phase

2017 ◽  
Vol 23 (38) ◽  
pp. 9018-9021 ◽  
Author(s):  
Pierre-Emmanuel Alexandre ◽  
Alexander Schwenger ◽  
Wolfgang Frey ◽  
Clemens Richert
Keyword(s):  
Gas Phase ◽  
Aromatic Hydrocarbons ◽  
High Loading ◽  
Uptake And Release

The gas phase reactivity of the dimethylchloronium ion with alkylbenzenes

1981 ◽  
Vol 59 (15) ◽  
pp. 2412-2416 ◽  
Author(s):  
John A. Stone ◽  
Margaret S. Lin ◽  
Jeffrey Varah
Keyword(s):  
High Pressure ◽  
Gas Phase ◽  
Mass Spectrometer ◽  
Aromatic Hydrocarbons ◽  
Relative Rate ◽  
Ion Source ◽  
Nucleophilic Displacement ◽  
Rate Of Reaction ◽  
Displacement Reactions ◽  
Bonded Complexes

The reactivity of the dimethylchloronium ion with a series of aromatic hydrocarbons has been studied in a high pressure mass spectrometer ion source using the technique of reactant ion monitoring. Benzene is unreactive but all others, from toluene to mesitylene, react by CH3+ transfer to yield σ-bonded complexes. The relative rate of reaction increases with increasing exothermicity in line with current theories of nucleophilic displacement reactions.

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