Generation, entrapment and reactivity of long-lived organic carbocations and radical cations within a supramolecular assembly: Ca Y zeolite

Abstract

Diarylethenes spontaneously form the corresponding radical cations and carbocations upon inclusion within activated Ca Y zeolite; oxygen plays an important role in the generation of the radical cations.

A unified approach to zeolites as acid catalysts and as supramolecular hosts exemplified

“…55 More recently, the same blue species has also been observed upon adsorption of 1,1-diphenylethylene in HY zeolite. 56,57 Although in one report the species was once again wrongly assigned to a radical cation, 56 our EPR measurements con- firmed earlier results on silica-alumina that the species cannot have an unpaired electron. 57 By generating the same blue species in solution, we have been able to record the 13 C NMR spectrum of the deep blue solutions and show that the species responsible for the intense colour is only present in trace amounts, below the detection limit of the 13 C NMR technique.…”

Energy transfer, proton transfer and electron transfer reactions within zeolites

“…In this section the thermal behavior of three alkenes, indene, 35 4-vinylanisole 36 and 1,1-diarylethylene, 37 within CaY is outlined. 38 In all cases CaY was activated in an oven at 500 °C; activation at 400 °C under vacuum resulted in a less active zeolite.…”

Dual Behavior of ZSM-5 as Brønsted Acid and Electron Acceptor in the Adsorption ofN,N′-Diphenylhydrazine

“…On the other hand, the zeolite-induced conversion of 1,1-diphenylethylene was ascribed to dual pathways initiated at different sites. [22] The conclusion that the divergent products are generated by different ZSM-5 sites suggests the interesting experiment to determine the product distribution obtained with a series of ZSM-5 samples containing exclusively Brønsted or exclusively Lewis sites. However, this intriguing experiment has not been possible to date.…”

“…[21] [22] In this paper we report the conversion of N,NЈ-diphenylhydrazine (DPH) to azobenzene (AB) upon adsorption onto acid H-ZSM-5; herein, the dehydrogenation product is accompanied by a reduced bond-cleavage product, aniline (AN). Diffuse reflectance optical spectroscopic results lead us to suggest that DPH…”