Spectroscopic and Structural Studies of Difluorophosphoryl Azide F<sub>2</sub>P(O)N<sub>3</sub>, Difluorophosphoryl Isocyanate F<sub>2</sub>P(O)NCO, and Difluorophosphoric Acid Anhydride, F<sub>2</sub>(O)POP(O)F<sub>2</sub>
作者:Xiaoqing Zeng、Michael Gerken、Helmut Beckers、Helge Willner
DOI:10.1021/ic902524u
日期:2010.3.15
Difluorophosphoryl azide, F2P(O)N-3, was fully characterized by F-19, P-31, N-14, and N-15 NMR, as well as by IR (gas, Ar-matrix), and Raman (liquid, solid) spectroscopy, For comparison the vibrational spectra of the isoelectronic difluorophosphor isocyanate, F2P(O)NCO was also studied. Both molecules were found to exist as single rotamers in the gas, liquid, and solid states. Their solid-state structures were determined by X-ray crystallography as the rotamers with the P=O bond being cis to the pseudohalide groups (with respect to the P-N bond). The F2P(O)N-3 molecule exhibits approximate C-s symmetry (phi(O1P1-N1N2) = -0.7(3)degrees), while F2P(O)NCO is significantly distorted from C-s symmetry (phi(O1P1-N1C1) = -18.9(5)degrees) because of intermolecular C center dot center dot center dot O contacts. The crystal structure of difluorophosphoric acid anhydride, F-2(O)POP(O)F-2, was also determined, possessing crystallographic C-2 symmetry with the two F2PO groups slightly staggered by 10.66(7)degrees along the P center dot center dot center dot P vector, and a P-O-P angle of 140.89(10)degrees for the bridging oxygen atom. The experimental results are supported by quantum chemical calculations, and the conformational properties of F2P(O)N-3 and F2P(O)NCO are discussed.