Encapsulating Photoluminescent Materials in Zeolites. Crystal Structure of Fully Dehydrated Zeolite Y (Si/Al = 1.69) Containing Eu3+

Abstract

Photoluminescent materials may acquire long-term stability and modified luminosity by encapsulation in zeolites. A single crystal of Eu,Tl–Y (FAU, Si/Al = 1.69) was prepared by Tl+-exchange of Na–Y (|Na71(H2O)x|[Si121Al71O384]) to give fully Tl+-exchanged zeolite Y, followed by Eu3+ exchange. It was then dehydrated at 623 K and 3 × 10–4 Pa. Its structure (Eu,Tl–Y, Eu17.3Tl19.0–Y, or |Eu4O44+3.3Eu3+4.1Tl+19.0H+26.4Al(OH)4–1.5|[Si121Al69.5H6.0O384]–FAU; no intact H2O molecules are present) was determined by single-crystal crystallography using synchrotron X-radiation. It was refined in the space group Fd3m (a = 24.915(1) A) with all 1105 unique data to R1 = 0.059 (Fo > 4σ(Fo)) and R2 = 0.162. Eu3+ replaced 73% of the Tl+ ions during ion exchange. The 17.3 Eu3+ ions per unit cell occupy three crystallographically distinct cation sites: 0.6 ion is octahedral at site I, 3.6 ions are trigonal at site I′, and 13.2 ions, also octahedral, occupy a second site I′. The latter are members of Eu4O44+ clusters, tetrah...