共 92 条
TETRAFLUOROPHOSPHITE, PF4-, ANION
被引:73
作者:
CHRISTE, KO
DIXON, DA
MERCIER, HPA
SANDERS, JCP
SCHROBILGEN, GJ
WILSON, WW
机构:
[1] ROCKETDYNE, CANOGA PK, CA 91309 USA
[2] MCMASTER UNIV, DEPT CHEM, HAMILTON L8S 4M1, ON, CANADA
关键词:
D O I:
10.1021/ja00086a018
中图分类号:
O6 [化学];
学科分类号:
0703 ;
摘要:
N(CH3)(4)(PF4-)-P-+, the first example of a PF4- salt, has been prepared from N(CH3)(4)F and PF3 using either CH3CN, CHF3, or excess PS as a solvent. The salt is a white, crystalline solid which is thermally stable up to 150 degrees C, where it decomposes to N(CH3)(3), CH3F, and PF3. The structure of;the PF4- anion was studied by variable temperature P-31 and F-19 NMR spectroscopy, infrared and Raman Spectroscopy, SCF, MP2, local and nonlocal density functional calculations, a normal coordinate analysis, and single-crystal X-ray diffraction. The anion possesses a pseudo trigonal bipyramidal structure with two longer axial bonds and an equatorial plane containing two shorter equatorial bonds and a sterically active free valence electron pair. In solution, it undergoes an intramolecular exchange process by the way of a Berry pseudorotation mechanism. The vibrational frequencies observed for PF4- in solid N(CH3)(4)PF4 are in excellent agreement with those calculated for free gaseous PF4-. The X-ray diffraction study (tetragonal, space group P42(1)m, a = 8.465(3) Angstrom, c = 5.674(2) Angstrom, Z = 2, R = 0.0723 for 268 observed [F greater than or equal to sigma(F)] reflections suffers from a 3-fold disorder with unequal occupancy factors for the equatorial fluorine atoms of PF4- but confirms its pseudo trigonal bipyramidal structure and the axial P-F bond length calculated for the free ion.
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页码:2850 / 2858
页数:9
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