Phosphinimine–borane combinations in frustrated Lewis pair chemistry†
Abstract
The phosphinimines Ph3PNR (R = Ph 1, C6F52, 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 H2 resulted in the formation of the corresponding salts [Ph3PN(H)R][HB(C6F5)3] (R = Ph 5, C6F56, tBu 7). Reaction of 1 or 2 with B(C6F5)3 and carbon dioxide afforded Ph3PN(R)COOB(C6F5)3 (R = Ph 8, C6F59) 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 PhCCH proceeds to give either deprotonation or addition affording products of the form [Ph3PN(H)R][PhCCB(C6F5)3] or (Ph3PNR)(Ph)CCH(B(C6F5)3). The factors governing the nature of the dominant products are considered.
- This article is part of the themed collection: Boranes and borohydrides