Onium Ions. 34. The Methoxydiazonium Ion: Preparation, 1H, 13C, and 15N NMR and IR Structural Studies, Theoretical Calculations, and Reaction with Aromatics. Attempted Preparation and the Intermediacy of the Hydroxydiazonium Ion

Article abstract of DOI:10.1021/ja00268a054

Nitrous oxide is methylated with CH3F -> SbF5 in SO2F2 or with CH3O(1+)SOClF in SO2ClF to give the stable methoxydiazonium ion CH3ON2(1+) (1), which was characterized by NMR (15N, 13C, 1H) and FT IR spectroscopic studies.It is stable below -30 deg C, above which it decomposes, regenerating N2O.When reacted with aromatics, such as toluene, 1 gives only methylation products and no methoxy derivatives are formed.Spectroscopic and chemical data indicate that the mesomeric form CH3O-N=N(1+) is a significant contributor to the overall structure of 1.Consideration of computed charge distribution (4-31 G with full geometry optimization and 4-31 G*) also supports this conclusion.Independent generation of 1 was also studied by solvolysis of methylazoxy triflate and diazotization of methoxylamine with NO(1+)BF4(1-).Preparation of the elusive hydroxydiazonium ion HON2(1+) (4) was attempted by protonation of nitrous oxide in superacids, but no long-lived ion could be observed.Diazotization of hydroxylamine with NO(1+)BF4(1-) gives nitrous oxide indicative of the intermediacy of 4.