Isolating individual chains of selenium by incorporation into the channels of a zeolite

Abstract

One of the disappointments to emerge from the recent intensive study of low-dimensional solids has been the increasing realization that relatively few of the investigated systems exhibit genuine one-or two-dimensional behaviour. Measured electronic and optical properties of crystalline and amorphous low-dimensional solids signify that there is significant interchain or interlayer perturbation. One possible way of eliminating such perturbation in so-called one-dimensional systems is to accommodate individual chains within the pores of a host dielectric material, which, preferentially, should itself be crystalline and well ordered. Here we report the use of combined high-resolution electron microscopy and computer simulation, to achieve the successful incorporation of chains of selenium into a synthetic mordenite, a zeolite which has one-dimensional channels (diameter ∼7 Å) running parallel to its c-axis. Remarkably, the uptake of selenium, which converts the white mordenite into an orange colour, occurs in a patchwise fashion leading to domains of occupied channels. The incorporation is readily accomplished thermally, and can be effected with a range of other zeolitic hosts, including ZSM-5, ZSM-23 and zeolites L and Y.