Phosphinimine-borane combinations in frustrated Lewis pair chemistry

The phosphinimines Ph3PNR (R = Ph 1, C6F5 2, tBu 3) are combined with B(C6F5)(3) in an effort to explore the frustrated Lewis pair (FLP) chemistry. While compound 1 is shown to form an adduct with the borane, compounds 2 and 3 exhibit no apparent interaction. Nonetheless exposure of each of the three combinations to H-2 resulted in the formation of the corresponding salts [Ph3PN(H)R][HB(C6F5)(3)] (R = Ph 5, C6F5 6, tBu 7). Reaction of 1 or 2 with B(C6F5)(3) and carbon dioxide afforded Ph3PN(R)COOB(C6F5)(3) (R = Ph 8, C6F5 9) while the corresponding reaction with 3 gave rise only to the tBuNCO and (Ph3PO) B(C6F5)(3). Reactions of 1-3 and B(C6F5)(3) with PhC=CH proceeds to give either deprotonation or addition affording products of the form [Ph3PN(H)R][PhC CB(C6F5)(3)] or (Ph3PNR)(Ph)C=CH(B(C6F5)(3)). The factors governing the nature of the dominant products are considered.