Substituent effect on electron affinity, gas-phase basicity, and structure of monosubstituted propynyl radicals and their anions: A theoretical study

✍ Scribed by Gab-Yong Lee

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 484 KB
• Volume: 30
• Category: Article
• ISSN: 0192-8651
• DOI: 10.1002/jcc.21216

✦ Synopsis

Abstract

The substituent effect of electron‐withdrawing groups on electron affinity and gas‐phase basicity has been investigated for substituted propynl radicals and their corresponding anions. It is shown that when a hydrogen of the α‐CH~3~ group in the propynyl system is substituted by an electron‐withdrawing substituent, electron affinity increases, whereas gas‐phase basicity decreases. These results can be explained in terms of the natural atomic charge of the terminal acetylene carbon of the systems. The calculated electron affinities are 3.28 eV (•CCCH~2~F), 3.59 eV (•CCCH~2~Cl) and 3.73 eV (•CCCH~2~Br), and the gas‐phase basicities of their anions are 359.5 kcal/mol (^−^:CCCH~2~F), 354.8 kcal/mol (:CCCH~2~Cl) and 351.3 kcal/mol (^−^:CCCH~2~Br). It is concluded that the larger the magnitude of electron‐withdrawing, the greater is the electron affinity of radical and the smaller is the gas‐phase basicity of its anion. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009