High-resolution fluorine-19 nuclear magnetic resonance spectroscopy. Studies of some Group V fluorophenyl derivatives

Abstract

The 19F n.m.r. spectra of (C6F5)nPh3-nE and (C6F5),Ph,-,P0(n = 1-3; E = P, As, and Sb) have been studied, and the spin-spin coupling constants are derived. The causes of broadening in the bis-and tris-pentafluorophenyl compounds are discussed. and l@F N.m.r. shifts of the phosphines ; tris-2.6-difluorophenylphosphine, tris-2.5-difluorophenylphosphine, and tris-2,3,6-trifluorophenylphosphine are also reported. The preparations of 2,5d if I uoro-and 2,3,6trif I uorophen yl-I it h i u m are given.MANY pentafluorophenyl compounds have been studied by 19F n.m.r. spectroscopy.1-3 In connection with the study of fluoroaryl Group V compounds and their metal complexes, the spectra of these ligands and some complexes with platinum and rhodium have been measured to determine whether correlations of the chemical shifts and the coupling constants with the structures exist.

Intramolecular Dehydrofluorinative Coupling of η5-Pentamethylcyclopentadienyl and Pentafluorophenylphosphine Ligands in Rhodium Complexes

“…δ −57, with phosphorus−fluorine coupling of 35−40 Hz. These data are similar to those of PhP(C 6 F 5 ) 2 …”

“…50% yield. The 31 P{ 1 H} NMR spectrum of 10 comprises a triplet at δ −32.6 with a value of 3 J PF of 37 Hz, comparable with the data for Ph 2 P(C 6 F 5 ) …”

1,2-Bis{(pentafluorophenyl)phenylphosphino}ethane: A Probe for Configurational Stability in Three-Legged Piano Stool Complexes

“…The spectrum was simulated using relative values of the 3 J PP , 3 J PF , 6 J PF , and 9 J PF coupling constants of 43.0, 33.0, 2.0, and 0 Hz, respectively, for resonances centered at δ −26.56 for 1a and at δ −26.43 for 1b . These coupling constants are similar to those of (C 6 H 3 F 2 -2,6) 2 PCH 2 CH 2 P(C 6 H 3 F 2 -2,6) 2 ( 3 J PP 47.2, 3 J PF 30.1, 6 J PF 1.2, and 9 J PF −0.4 Hz), and the chemical shifts are similar to that of PPh 2 (C 6 F 5 ) (δ −24.7) . The 19 F NMR spectrum shows only four resonances.…”