Supramolecular Chemistry Based on Frustrated Lewis Pairs – Reactions of an Al/P FLP with Potassium Formate and Cesium Fluoride

摘要

> Reactions of the Al/P‐based frustrated Lewis pair Mes ₂ P–C(Al t Bu ₂ )=C(H)–Ph ( 1 ) with the Br?nstedt acids HBr, HI, and HCO ₂ H resulted in the formation of the corresponding H X adducts Mes ₂ (H)P–C[Al( X ) t Bu ₂ ]=C(H)–Ph [ X = Br ( 4 ), I ( 5 ), OC(H)O ( 6 )]. Despite the well‐known sensitivity of Al–C bonds towards protolysis, the products were isolated in good yields. Short intramolecular distances between H and Br, I or O are consistent with the presence of P–H ··· X hydrogen bonds. Treatment of 1 with potassium formate or CsF yielded in poor to moderate yields the adducts Mes ₂ P–C(Al t Bu ₂ )=C(H)Ph · (KO ₂ CH) ( 7 ) and Mes ₂ P–C(Al t Bu ₂ )=C(H)Ph · (CsF) ( 8 ). The potassium compounds required the presence of additional solvent molecules to obtain isolable crystalline products. Two monomeric units were joined by interactions of each K + cation with two formate anions. Supramolecular entities resulted by the additional coordination of the K + cations to solvent molecules ( 7a , toluene; 7b , 1,2‐difluorobenzene; 7c , THF), weak contacts to a mes