Metastable Decompositions of gem-Dimethoxyalkanes, (RR'C(OCH3)2), upon Electron Impact. II. 1,1- and 2,2-Dimethoxypropanes.

Metastable decompositions of gem-dialkoxyalkanes upon electron impact. III. Diethoxymethane (CH2(OCH2CH3)2)

“…In previous papers,1,, 9,, 10 in order to examine the interaction of the two alkoxy groups, unimolecular metastable decomposition of several gem‐dialkoxyalkanes has been investigated. In those papers we reported that the sequential transfers of a methyl group and a hydrogen atom to the other ether oxygen occur during the decompositions of the m/z 75 ions [M − ; H] + from dimethoxymethane (CH 2 (OCH 3 ) 2 , 2 ), [M − CH 3 ] + from 1,1‐dimethoxyethane (CH 3 CH(OCH 3 ) 2 , 3 ) and [M − CH 3 CH 2 ] + from 1,1‐dimethoxypropane (CH 3 CH 2 CH(OCH 3 ) 2 , 4 ) and of the m/z 89 ions ([M − H] + from 3 and [M − CH 3 ] + from 2,2‐dimethoxypropane ((CH 3 ) 2 C(OCH 3 ) 2 , 5 ) into the m/z 47 ion.…”

Metastable ion study of organosilicon compounds. Part XIII: dimethoxydimethylsilane, (CH3)2Si(OCH3)2, and dimethoxymethylsilane, CH3SiH(OCH3)2

“…The latter is an imaginary reaction that occurs by the migration of a methyl in the methoxy group to the other ether oxygen, in a similar manner to the corresponding carbon analogue. 8,9 From Fig. 3, although H f of CH 3 OSi C C CH 3 OCH 3 is higher than that of CH 3 SiO C C CH 3 OCH 3 , as described above, the energy of the transition state of the latter reaction is 66 kJ mol 1 higher than that of the former.…”

“…This is different than the case of 3 Cž , because in that case a methyl group in the methoxy group migrates to the other ether oxygen during the elimination of CH 3 OCH 3 . 8,9 If the mechanism Figure 3 shows the energy diagram obtained with a semi-emprical MO calculation method (AM1). The total heat of formation H f of CH 3 Si C HOCH 3 C CH 2 O is 101 kJ mol 1 lower than that of CH 3 OSi C C CH 3 OCH 3 .…”

“…8,9 The ion at m/z 89 in the carbon analogue eliminates predominantly a CH 3 OCH 3 in the metastable time window. 8,9 These results require further consideration, because 1 ). As shown in Fig.…”

Complex Acts of Knowing: Paradox and Descriptive Self‐Awareness

“…The MIKE spectrum (not shown) of the source‐generated m / z 99 ions indicates that these ions eliminate essentially exclusively a 28 Da neutral species to give the m / z 71 ions. From this result alone, we cannot confirm whether the neutral species is CO or C 2 H 4 , although this type of precursor ion generally eliminates CO 19, 20. However, in this case the value of ΣΔ H f of (CH 3 ) 2 SiCH + + CO is 119 kJ mol −1 higher than that of H 2 SiCHCO + + C 2 H 4 as estimated from the Δ H f values listed in Table 1.…”