The gas-phase ion chemistry of methyl hydroperoxide (1) was investigated by mass spectrometric and theoretical methods. The proton affinity of 1, 173.3 ± 2 kcal mol−1 measured by the FT-ICR bracketing technique and the kinetic method, is in excellent agreement with the value of 172.6 ± 2 kcal mol−1 from G2 ab initio calculations, which identify the α oxygen atom as the most basic site. Methylation of 1 by (CH3)2F+ gives a mixed population of ions methylated at both oxygen atoms. The experimental proton affinity of CH3OOCH3 is 176.2 ± 4 kcal mol−1, versus a theoretically computed value of 180.4 ± 2 kcal mol−1, the most nucleophilic site being again the α oxygen atom. Nitrosation of 1 yields a (CH3OOH·NO)+ adduct that behaves as both a nitrosating and a protonating agent. The results are discussed and compared with earlier pertinent studies.
Gas-Phase Positive and Negative Ion Chemistry of Methyl Hydroperoxide / M., Aschi; M., Attinà; Cacace, Fulvio; Cipollini, Romano; Pepi, Federico. - In: INORGANICA CHIMICA ACTA. - ISSN 0020-1693. - STAMPA. - 275-276:(1998), pp. 192-202. [10.1016/S0020-1693(97)06077-5]
Gas-Phase Positive and Negative Ion Chemistry of Methyl Hydroperoxide.
CACACE, Fulvio;CIPOLLINI, Romano;PEPI, Federico
1998
Abstract
The gas-phase ion chemistry of methyl hydroperoxide (1) was investigated by mass spectrometric and theoretical methods. The proton affinity of 1, 173.3 ± 2 kcal mol−1 measured by the FT-ICR bracketing technique and the kinetic method, is in excellent agreement with the value of 172.6 ± 2 kcal mol−1 from G2 ab initio calculations, which identify the α oxygen atom as the most basic site. Methylation of 1 by (CH3)2F+ gives a mixed population of ions methylated at both oxygen atoms. The experimental proton affinity of CH3OOCH3 is 176.2 ± 4 kcal mol−1, versus a theoretically computed value of 180.4 ± 2 kcal mol−1, the most nucleophilic site being again the α oxygen atom. Nitrosation of 1 yields a (CH3OOH·NO)+ adduct that behaves as both a nitrosating and a protonating agent. The results are discussed and compared with earlier pertinent studies.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.