Frustrated Lewis Pair in Zeolite Cages for Alkane Activations

The frustrated Lewis pair (FLP) concept in homogeneous catalysis was extended to heterogeneous catalysis via the supramolecular system of FLP between deprotonated zeolite framework oxygens and confined carbocations in methanol-to-olefin (MTO) reactions. In this FLP, the polymethylbenzenium (PMB+) functioned as the Lewis acid to accept an electron pair, and the deprotonated framework oxygen site acted as the Lewis base to donate an electron pair. This FLP theoretically demonstrated the ability to undergo H-2 heterolysis and alkanes dehydrogenation, and this was further confirmed by gas chromatography-mass spectrometer (GC-MS) catalytic experiments inside FLP-containing chabazite zeolites. All these findings not only bring new recognition to the carbocation chemistry in zeolite cages but also put forward a new reaction pathway as one part of MTO reactions.