Stereochemical effects in the gas-phase pinacol rearrangement. 2. Ring contraction versus methyl migration in cis- and trans-1,2-dimethylcyclohexane-1,2-diol

1988 ◽  
Vol 110 (4) ◽  
pp. 1098-1103 ◽  
Author(s):  
Giulia. De Petris ◽  
Pierluigi. Giacomello ◽  
Adriano. Pizzabiocca ◽  
Gabriele. Renzi ◽  
Maurizio. Speranza
Keyword(s):  
Gas Phase ◽  
Ring Contraction ◽  
Pinacol Rearrangement ◽  
Cis And Trans ◽  
In Cis

scholarly journals Bethe-Salpeter Study of the Optical Absorption of trans and cis Azobenzene-Functionalized Metal-Organic Frameworks using Molecular and Periodic Models

2021 ◽  
Author(s):  
Aseem Rajan Kshirsagar ◽  
Claudio Attaccalite ◽  
Xavier Blase ◽  
Jing Li ◽  
Roberta Poloni
Keyword(s):  
Optical Absorption ◽  
Gas Phase ◽  
Metal Organic Framework ◽  
Molecular Models ◽  
Gw Approximation ◽  
Periodic Models ◽  
Metal Organic ◽  
Reasonable Description ◽  
Cis And Trans ◽  
In Cis

The optical absorption spectra of the azobenzene-functionalized metal-organic framework, PCN-123, are calculated in cis and trans configurations using the Bethe-Salpeter equation (BSE) formalism and the GW approximation using periodic and non-periodic models. In the visible, near-UV and mid-UV region the optical excitations in the MOF are associated with the azobenzene functionalities and this results in spectral features similar to the case of the gas phase azobenzene and the azo-functionalized ligand. The most noticeable difference is the significantly more intense S<sub>1</sub> band for cis in the MOF as compared to the free molecules which points to a faster and more complete cis→trans isomerization in the framework, with strong implications for the design of MOFs with high photoconversion efficiencies. Consistent with these findings, all the molecular models employed to represent the MOF, including the smallest, are found to yield a reasonable description of the low energy optical spectra (between 2 and 5 eV) of the periodic framework, with the exception of the stronger S<sub>1</sub> band of cis in the MOF, a feature that we attribute to a limitation of the fragment model to correctly represent the wavefunction of the extended framework.

scholarly journals Bethe-Salpeter Study of the Optical Absorption of trans and cis Azobenzene-Functionalized Metal-Organic Frameworks using Molecular and Periodic Models

2021 ◽  
Author(s):  
Aseem Rajan Kshirsagar ◽  
Claudio Attaccalite ◽  
Xavier Blase ◽  
Jing Li ◽  
Roberta Poloni
Keyword(s):  
Optical Absorption ◽  
Gas Phase ◽  
Metal Organic Framework ◽  
Molecular Models ◽  
Gw Approximation ◽  
Periodic Models ◽  
Metal Organic ◽  
Reasonable Description ◽  
Cis And Trans ◽  
In Cis

The optical absorption spectra of the azobenzene-functionalized metal-organic framework, PCN-123, are calculated in cis and trans configurations using the Bethe-Salpeter equation (BSE) formalism and the GW approximation using periodic and non-periodic models. In the visible, near-UV and mid-UV region the optical excitations in the MOF are associated with the azobenzene functionalities and this results in spectral features similar to the case of the gas phase azobenzene and the azo-functionalized ligand. The most noticeable difference is the significantly more intense S<sub>1</sub> band for cis in the MOF as compared to the free molecules which points to a faster and more complete cis→trans isomerization in the framework, with strong implications for the design of MOFs with high photoconversion efficiencies. Consistent with these findings, all the molecular models employed to represent the MOF, including the smallest, are found to yield a reasonable description of the low energy optical spectra (between 2 and 5 eV) of the periodic framework, with the exception of the stronger S<sub>1</sub> band of cis in the MOF, a feature that we attribute to a limitation of the fragment model to correctly represent the wavefunction of the extended framework.

The α(C—C)/β(C—H) ratio of the primary processes in the 184.9 nm photolysis of gaseous cis- and trans-2-butene

1987 ◽  
Vol 65 (7) ◽  
pp. 1631-1638 ◽  
Author(s):  
Hélène Deslauriers ◽  
Wlodzimiercz Makulski ◽  
Guy J. Collin
Keyword(s):  
Quantum Yield ◽  
Gas Phase ◽  
Molecular Property ◽  
Bond Rupture ◽  
Complete Study ◽  
Yield Values ◽  
In Trans ◽  
Cis And Trans ◽  
In Cis

A complete study of the 184.9 nm photolysis of cis- and trans-2-butene has been done in the gas phase. The main primary processes (>90%) are the α(C—C) and β(C—H) bond ruptures. Both processes have similar quantum yield values in cis-2-butene: [Formula: see text]. Conversely, the α(C—C) bond rupture is more important in trans-2-butene: [Formula: see text]. These values are compared with those measured in propene (0.57) and isobutene (0.95). No simple molecular property seems sufficient to explain such an effect.

Stereochemical effects in the gas-phase pinacol rearrangement of cis- and trans-1,2-dimethylcyclopentane-1,2-diol

1986 ◽  
Vol 108 (24) ◽  
pp. 7491-7495 ◽  
Author(s):  
Giulia. De Petris ◽  
Pierluigi. Giacomello ◽  
Tito. Picotti ◽  
Adriano. Pizzabiocca ◽  
Gabriele. Renzi ◽  
...  
Keyword(s):  
Gas Phase ◽  
Pinacol Rearrangement ◽  
Cis And Trans

scholarly journals Hydrogen Peroxide Oxidation of Coordinated Thiocyanate Ion in cis- and trans-[Coen2NH3NCS]2+: The Preparation and Properties of trans-[Coen2NH3CN]2+

1973 ◽  
Vol 51 (24) ◽  
pp. 4152-4158 ◽  
Author(s):  
Albert Richard Norris ◽  
James William Lennox Wilson
Keyword(s):  
Hydrogen Peroxide ◽  
Spectral Properties ◽  
Peroxide Oxidation ◽  
Reaction Conditions ◽  
Thiocyanate Ion ◽  
Hydrogen Peroxide Oxidation ◽  
Percent Conversion ◽  
Cis And Trans ◽  
In Cis

The hydrogen peroxide oxidation of thiocyanate ion in cis- and trans-[Coen2NH3NCS]2+ leads to the formation of the corresponding cis- and trans-cyanoammine- and diamminebis(ethylenediamine)cobalt-(III) complexes. The spectral properties of the previously unreported trans-[Coe2NH3CN]2+ are reported and compared to the spectral properties of the cis-isomer.Observations are made concerning the reaction conditions which favor a high percent conversion of trans-[Coen2NH3NCS]2+ to trans-[Coen2NH3CN]2+.

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