1421330-96-2Relevant academic research and scientific papers
The Lewis acidity of fluorophosphonium salts: Access to mixed valent phosphorus(iii)/(v) species
Hounjet, Lindsay J.,Caputo, Christopher B.,Stephan, Douglas W.
, p. 2629 - 2635 (2013/03/28)
Oxidative fluorination of the electron-deficient phosphine Ph 2P(C6F5) using XeF2, followed by fluoride ion abstraction from the resulting difluorophosphorane Ph 2P(F)2(C6F5), produces electrophilic fluorophosphonium salts [Ph2P(F)(C6F5)][X] (X = FB(C6F5)3 or O3SCF3). Variable temperature NMR spectroscopic analysis of [Ph2P(F)(C 6F5)][FB(C6F5)3] demonstrates a fluxional process attributed to fluoride ion exchange between B(C6F5)3 and [Ph2P(F)(C 6F5)]+, suggesting that these species have comparable Lewis acidities. This exchange can also be illustrated by adding phosphine Ph3P to [Ph2P(F)(C6F 5)][FB(C6F5)3] at ambient temperature to produce Ph2P(F)2(C6F 5) and Ph3P-B(C6F5)3, while heating this mixture results in thermally induced para-substitution of Ph3P at the C6F5 group of the phosphonium ion to generate [Ph3P(C6F4)P(F)2Ph 2][FB(C6F5)3]. Such frustrated Lewis pair reactivity also can be exploited by reacting [Ph2P(F)(C 6F5)][O3SCF3] with silylphosphine Ph2PSiMe3 to afford the unique mixed-valent salt [Ph 2P(C6F4)P(F)Ph2][O 3SCF3], which upon the addition of fluoride is converted to Ph2P(C6F4)P(F)2Ph2. XeF2 reacts with [Ph2P(C6F4)P(F) Ph2][O3SCF3] at ambient temperature, producing equal proportions of the dicationic salt [Ph2P(F)(C6F 4)P(F)Ph2][O3SCF3]2 and the bis(difluorophosphorane) Ph2P(F)2(C6F 4)P(F)2Ph2, the latter of which can then be quantitatively converted to the former by adding one equiv of Me 3SiO3SCF3.
