Polyheteroatom Cations of Halogens with Oxygen or Nitrogen

Polyheteroatom Cations of Halogens with Oxygen or Nitrogen. 

Strahle and co-workers971 were the first to report the synthesis of the dichloroni-tronium ion [Eq. (4.226)]. According to X-ray crystal structure analysis of the hexachloroantimonate salt, which shows a remarkable stability up to 145°C, the cation is almost planar (maximum deviation from the plane is 0.038 A) and has Cs symmetry. The N—O bond distance is 1.31 A, that is, lies between the length of a NO single bond (1.151 A) and a NO double bond (1.47 A). This is indicative of a decreased Tt-bond contribution, which is also reflected in the IR spectrum (stretching vibration at 1650 cm 1 as compared to 1827 cm-1 of phosgene). 

An improved method developed by Minkwitz et al.972 allowed to obtain other salts [Eq. (4.227)]. The structure of the cation was characterized by vibrational spectroscopy, 14N NMR (a single peak at 814N -282 from CH3N02), and by ab initio theory. 

An ionic structure for the complex between NF30 and AsF5 was suggested by Bartlett et al.,973 which was subsequently proved by Christe and Maya967 by preparing and characterizing (IR, X-ray) stable salts [Eq. (4.228)]. The 19F NMR spectrum of 

The mixed halonitronium ion ClENO+ has been obtained by Minkwitz et al.975 by oxidative fluorination of ONC1 [Eq. (4.230)]. The ion has much lower stability than the difluoro analog. Subsequently, however, the validity of the structure determination of both Cl2NO+ and ClFNO+ was questioned on the basis of large discrepancies between experimental and theoretical vibrational spectra.978,979 

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