Fluoro‐nitrogen Cations

Abstract

The crystal structures of [NH3F]+[CF3SO3]−, [NH2F2]+[SbF6]−, and [N2F3]+[Sb3F16]− have been determined, representing the first structural characterizations of these simple fluoro‐nitrogen cations. The influences of the hybridization of the central nitrogen atom and of the number of fluorine substituents on the N−F bond lengths are evaluated for the series N2F+, N2F3+, NF2O+, NH3F+, NH2F2+, and NF4+. It is shown that the N−F bond length decreases from 1.40 Å to 1.26 Å with increasing fluorine substitution and increasing s‐character of the nitrogen atom, and that unusual N−F bond lengths reported in the previous literature are caused by disorder problems

Extreme NMR shielding in fluoro-nitrogen cations

“…† There is excellent agreement between the calculated geometries and available experimental and high-level theoretical data. The present CCSD(T)-F12b/cc-pVQZ-F12 geometries are in agreement with the previous results of Christe 16 at the same level of theory for NNF + , NH 3 F + , NH 2 F 2 + , NHF 3 + , NF 4 + , and ONF 2…”

“…Cations with N-F bonds have found applications in high energy density materials, rocket propellents, powerful oxidizing agents, and electrophilic fluorinating agents. [12][13][14][15][16] Until recently, few X-ray crystal structures of N-F cations were available. However, Christe has reported crystal structures of NH 3 F + , NH 2 F 2 + , and N 2 F 3 + .…”

“…However, Christe has reported crystal structures of NH 3 F + , NH 2 F 2 + , and N 2 F 3 + . 16 Together with N 2 F + , ONF 2 , and NF 4 + , these are all stable salts at ambient temperature that enable solid-state and solution studies to be conducted. Cremer and Kraka have recently proposed new classes of fluorinating agents from a theoretical investigation of N-F containing molecules.…”

“…The set of molecules is derived from Cremer and Kraka's potential fluorinating agents 17,18 and Christe's crystallographically characterised N-F cations. 16 This set of N-F containing cations offers a severe test of computational methods in the prediction of NMR shielding constants. While experimental 19 F and 15 N chemical shifts are available for several of these compounds, results from our theoretical studies will provide an accurate reference for future experimental studies.…”