The ketene–water radical cation dipole complex [CH₂CO·H₂O]˙⁺

Abstract

The [C2H4O21.+ ion [CH2CO(OH2)]-+ is a stable gas phase species which behaves as a ketene radical cation-water (dipole) complex.

Formaldehyde mediated proton-transport catalysis in the ketene–water radical cation CH2C(O)OH2+

“…At internal energies in excess of only a few kcal mol −1 above 1a/1b, the water molecule can freely move from carbon to carbon. The sum of the product energies relative to 1a was calculated to be 15 kcal mol −1 [9] which reasonably agrees with our CBS-QB3 result of 13.4 kcal mol −1 .…”

“…Such an experiment could not be performed with the instrumentation of the study of Ref. [9] but our threesector ZAB-R magnetic deflection instrument does have this capability.…”

“…In 1986 Postma et al [9] provided experimental and supporting computational evidence that the source generated C 2 H 4 O 2…”

“…Appearance energy measurements of the m/z 60 ion [9] yielded an apparent heat of formation of 138 kcal mol −1 which was interpreted to correspond to the formation of 1 at the thermochemical threshold. This implies that the abundant loss of CH 2 O from low-energy ions DHA-1 -the MI spectrum of DHA-1 is dominated by a simple Gaussian shaped peak [11] at m/z 60 corresponding with a T 0.5 value of 25 meV -would also yield C 2 H 4 O 2…”

“…In the early ab initio calculations of Postma et al [9], the RHF/4-31G level of theory was used to optimize the geometries of various configurations of the ketene-water ion. Our CBS-QB3 calculations agree with their findings that ion 1a and the hydrogen-bridged radical cation 1b, whose optimized geometries are shown in Fig.…”