Hanzlová E, Váňa J, Shaffer CJ, Roithová J, Martinů T. Evidence for the cyclic CN2 carbene in the gas phase.
Org Lett 2014;
16:5482-5. [PMID:
25296289 DOI:
10.1021/ol5027602]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
3-Halodiazirine-3-carboxylic acids (c-CN2XCOOH, X = Cl or Br) were prepared from their esters and converted to the corresponding sodium salts. Collision-induced dissociation (CID) of the carboxylate ions led exclusively to the loss of CO2 and the resulting c-CN2X(-) ions dissociated to c-CN2 carbene at low energies. The bond dissociation energy (BDE) for c-CN2Br(-) was found to be less than 8 kcal/mol using CID of the anion generated by electrospray ionization of the carboxylate. The analogous difluoro system (CF2XCOOH/CF2X(-)/CF2) exhibits similar dissociative behavior. All experimental BDEs are in very good agreement with MP4/aug-cc-pVTZ calculations.
Collapse