Complete filling of zeolite frameworks with polyalkynes formed in situ by transition-metal ion catalysts

Alvaro, M., Cardin, D.J., Colquhoun, H.M., Garcia, H., Gilbert, A., Lay, A. K. and Thorpe, J.H. (2005) Complete filling of zeolite frameworks with polyalkynes formed in situ by transition-metal ion catalysts. Chemistry of Materials, 17 (10). pp. 2546-2551. ISSN 0897-4756 doi: 10.1021/cm040175y

Abstract/Summary

We report the use of transition-metal-exchanged zeolites as media for the catalytic formation and encapsulation of both polyethyne and polypropyne, and computer modeling studies on the composites so formed. Alkyne gas was absorbed into the pores of zeolite Y (Faujasite) exchanged with transition-metal cations [Fe(II), Co(II), Cu(II), Ni(II), and Zn(II)]. Ni(II) and Zn(II) were found to be the most efficient for the production of poly-ynes. These cations were also found to be effective in polymer generation when exchanged in zeolites mordenite and beta. The resulting powdered samples were characterized by FTIR, Raman, diffuse reflectance electronic spectroscopy, TEM, and elemental analysis, revealing, nearly complete loading of the zeolite channels for the majority of the samples. Based on the experimental carbon content, we have derived the percentage of channel filling, and the proportion of the channels containing a single polymer chain for mordenite. Experimentally, the channels for Y are close to complete filling for polyethyne (PE) and polypropyne (PP), and this is also true for polyethyne in mordenite. Computer modeling studies using Cerius2 show that the channels of mordenite can only accept a single polymer chain of PP, in which case these channels are also completely filled.