Steric Effects in Isolated Molecules: Gas-Phase Basicity of Methyl-Substituted Acetophenones

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22310%2F05%3A00013521" target="_blank" >RIV/60461373:22310/05:00013521 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/61388963:_____/05:00021133 RIV/00216275:25310/05:00002643

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Steric Effects in Isolated Molecules: Gas-Phase Basicity of Methyl-Substituted Acetophenones

Popis výsledku v původním jazyce

The energies of 14 methyl-substituted acetophenones and of their protonated forms were calculated within the framework of the density functional theory at the B3LYP/6-311+G(d,p) level. The gas-phase basicities of some members of this series were measuredusing Fourier transform ion cyclotron resonance mass spectrometry in order to complete the known data. The protonated forms exist in two configurations differing in the position of the hydrogen atom; their equilibrium depends strongly on the substitution pattern. Taking into account all conformational equilibria, the experimental and calculated basicities agreed to within 2.7 kJ mol-1. Substituent effects were tentatively resolved into polar and steric contributions by comparing the corresponding orthoand para derivatives. The steric effect of the ortho-methyl groups defined in this way has a clear physical meaning proven by several correlations; it destabilizes the neutral acetophenone molecules but destabilizes the cations even more

Název v anglickém jazyce

Steric Effects in Isolated Molecules: Gas-Phase Basicity of Methyl-Substituted Acetophenones

Popis výsledku anglicky

The energies of 14 methyl-substituted acetophenones and of their protonated forms were calculated within the framework of the density functional theory at the B3LYP/6-311+G(d,p) level. The gas-phase basicities of some members of this series were measuredusing Fourier transform ion cyclotron resonance mass spectrometry in order to complete the known data. The protonated forms exist in two configurations differing in the position of the hydrogen atom; their equilibrium depends strongly on the substitution pattern. Taking into account all conformational equilibria, the experimental and calculated basicities agreed to within 2.7 kJ mol-1. Substituent effects were tentatively resolved into polar and steric contributions by comparing the corresponding orthoand para derivatives. The steric effect of the ortho-methyl groups defined in this way has a clear physical meaning proven by several correlations; it destabilizes the neutral acetophenone molecules but destabilizes the cations even more

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

CC - Organická chemie

OECD FORD obor

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Projekt

<a href="/cs/project/LN00A032" target="_blank" >LN00A032: Struktura a dynamika komplexních molekulových systémů a biomolekul</a><br>

Návaznosti

Z - Vyzkumny zamer (s odkazem do CEZ)

Rok uplatnění

2005

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

European Journal of Organic Chemistry

ISSN

1434-193X

e-ISSN

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Svazek periodika

2005

Číslo periodika v rámci svazku

12

Stát vydavatele periodika

DE - Spolková republika Německo

Počet stran výsledku

9

Strana od-do

2580-2588

Kód UT WoS článku

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EID výsledku v databázi Scopus

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