Formation of the high-energy isomer HSiO+ by chemical reaction in the gas phase

✍ Scribed by Arnold Fox; Diethard K. Bohme

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 323 KB
• Volume: 187
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(91)80297-b

✦ Synopsis

The high-energy isomer HSiO+ of protonated SiO has been generated by a fast O-atom transfer reaction between SiH* and N20 in helium and hydrogen buffer gases at 0.35 Torr and 295 k 2 K. Formation of HSiO* by O-atom transfer proceeds in competition with formation of the ground-state SiOH+ isomer, which is formally an Insertion reaction. Other insertion reactions were observed in the reactions of SiH+ with COa and SO*. The mechanism of insertion is rationalized in terms of sequential Oatom transfer and isomerization of HSiO+ to SiOH+ within the intermediate complex, where the isomerization may be achieved via a proton shuttle within the complex or unimolecularly, when suffkient excessenergy is available in the initial O-atom transfer. The high-energy isomer HSiO* does not convert to SiOH+ by reaction with H2 at the operating conditions of the experiments.

') The standard enthalpy changes for reaction are uncertain by about 5 kcal mol-'.