Fourier transform ion cyclotron resonance determination of lithium cation basicities by the kinetic method: upward extension of the scale to phosphoryl compounds

✍ Scribed by Buncel, Erwin; Chen, Austin; Decouzon, Michèle; Fancy, Sally Ann; Gal, Jean-François; Herreros, Marta; Maria, Pierre-Charles

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 275 KB
• Volume: 33
• Category: Article
• ISSN: 1076-5174
• DOI: 10.1002/(sici)1096-9888(199808)33:8<757::aid-jms676>3.0.co;2-0

✦ Synopsis

Lithium cation basicities (LCBs) are reported for a series of 16 phosphoryl compounds, including phosphine oxides, phosphinates, phosphonates and phosphates. The experiments were carried out using the kinetic method applied to Fourier transform ion cyclotron resonance mass spectrometry. Two di †erent data treatments of the Napierian logarithm of ion peak intensity ratios were compared : extrapolation to zero kinetic energy and weighted averaging of data over the range of energies studied. The e †ect of pressure on the LCB determinations was also studied. An increase in the pressure of the collision gas allows one to decrease the collision energy necessary for efficient dissociation of the lithium-bonded dimer, thus favoring the fragmentation pathway of lowest energy. Among the monofunctional ligands, the phosphoryl derivatives studied have the largest LCBs yet known. The previously published self-consistent LCB scale of Taft and co-workers was extended upward by 14 kJ mol-1.

1998 John ( Wiley & Sons, Ltd.