First Experimental Observation on Different Ionic States of thetert-Butoxy [(CH3)3CO.] Radical

Abstract

A continuous tert-butoxy (CH3)+CO* radical beam is produced in situ by respective pyrolysis of both (CH3)3CONO at 115(+/-0.5) degrees C and (CH3)3COOC(CH3)3 at 87(+/- 0.5) degrees C. By combining the HeI photoelectron (PE) spectrum with the improved density function theory (DFT) calculations, we have concluded that the (CH3)3CO* radical has C3V symmetry and X2E ground state. The study does not only provide the ionization energies of different ionic states of the (CH3)3CO* radical for the first time, but also the first example in which there have been similar vibrational structures in different ionic states caused by removal of the electron on an orbital. It is also pointed out that (CH3)3CONO is a good source for obtaining the (CH3)3CO* radical beam, and that NO is a stable regent for the active radical. The results will promote the studies in electron spin resonance (ESR) research on the mechanisms of both the initiation of the formation of a new radical and the radical-chain polymerization in which the (CH3)3CO* radical participates.

The diradical (CH3)2CHN and its isomeric molecule (CH3)2C=HN: Generation and characterization

“…In addition, NO is a good stabilizing reagent of some radicals. 18,23,24 III. G2 AND IMPROVED DFT CALCULATIONS "REF.…”

“…NO was found to be a stabilizing reagent of ͑CH 3 ͒ 3 CO radical in pyrolysis of ͑CH 3 ͒ 3 CONO 18 and used to generations of the nitrenes. 19,20,23 As a stabilizing reagent for some radicals, a possible explanation of the NO action is that once the diradicals RN ͑or RO͒ are generated on the surface of the molecular sieve, a complex species RN-NO between NO and RN may be formed, and then this species is quickly decomposed on photoionization point.…”

“…From a careful analysis of Bock's experimental process, it is obvious that: the pyrolysis temperature ͑higher than 620 K͒ was much too high to record the PES signals of the short-lived and unstable transient species, such as nitrenes in their PES experiment the distance from the pyrolysis point to the photoionization point was too long ͑maybe more than half meter͒. 2 Through pyrolysis of well-selected parent compounds, we reported a lot of the PES studies on reactive open-shell species, such as NO 3 , 14 CH 3 O, 15 CH 3 S, 15 CH 3 SS, 16 CH 3 CH 2 S, 17 and ͑CH 3 ͒ 3 CO. 18 Recently, both CH 3 N 19 radical and CH 3 CH 2 N 20 diradicals were obtained by respective pyrolysis of CH 3 N 3 at 145͑Ϯ0.5͒°and CH 3 CH 2 N 3 at 135͑Ϯ0.5͒°C, their PE spectra were also recorded in situ. But the pyrolysis details have not been discussed in detail.…”

Novel gaseous transient species: Generation and characterization

“…( 2 A′) [54] C 3v -(CH 3 ) 3 CO . ( 2 E) [55] Ionic Finally, the broad band at 15.20 eV can be tentatively assigned to transition of an electron on the 5a 1 orbital to the 3 E ionic state (Table 4). Similarly, ethoxy radical CH 3 CH 2 O .…”

“…Besides, the vacuum flash pyrolysis of (CH 3 ) 3 COOC(CH 3 ) 3 is another effective way of producing tert-butoxy radical (CH 3 ) 3 CO . at 87 (± 0.5)℃ with the catalysis of 20 Å molecular sieves, although side-products like CH 3 CH 3 and acetone (CH 3 ) 2 CO are also detected [55] . Due to the large electron donor property of the (CH 3 ) 3 C group, the first ionization band of (CH 3 ) 3 CO .…”