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Deprotonation and radicalization of glycine neutral structures

2007; Wiley; Volume: 21; Issue: 1 Linguagem: Inglês

10.1002/poc.1278

1099-1395

Gang Yang, Yuangang Zu, Lijun Zhou,

Electron Spin Resonance Studies

Abstract Ab initio calculations at MP2/6‐311++G(d,p) theoretical level were performed to study the deprotonation and radicalization processes of 13 glycine neutral structures (A. G. Császár, J. Am. Chem. Soc . 1992; 114 : 9568). The deprotonation processes to glycine neutral structures take place at the carboxylic sites instead of α ‐C or amido sites. Two carboxylic deprotonated structures were obtained with the deprotonation energies calculated within the range of 1413.27–1460.03 kJ · mol −1 , which are consistent with the experimental results. However, the radicalization processes will take place at the α ‐C rather than carboxylic O or amido sites, agreeing with the experimental results. Seven α ‐C radicals were obtained with the radical stabilization energies calculated within the range of 44.87–111.78 kJ · mol −1 . The population analyses revealed that the main conformations of the neutral or radical state are constituted by several stable structures, that is, the other structures can be excluded from the future considerations and thus save computational resources. Copyright © 2007 John Wiley & Sons, Ltd.