Benzene sorption complex of fully dehydrated fully Mn2+-exchanged zeolite Y (FAU) and its single-crystal structure

Abstract

The single-crystal structure of a benzene sorption complex of fully dehydrated fully Mn2+-exchanged zeolite Y, |Mn37.5(C6H6)24|[Si117Al75O384]-FAU, has been determined by single-crystal synchrotron X-ray diffraction techniques in the cubic space group Fd \( \overline{3} \) m at 100(1) K. A fully dehydrated and fully Mn2+-exchanged zeolite Y (|Mn37.5|[Si117Al75O384]-FAU, Si/Al = 1.56) was treated with zeolitically dried benzene at 297(1) K for 3 days. The structure was refined using all intensities to the final error indices (using the 544 reflections for which F o > 4σ(F o)) R 1 = 0.050 (based on F) and wR 2 = 0.147 (based on F 2). In this structure, Mn2+ ions occupy four crystallographic sites: 13.5 Mn2+ ions are at the centers of the double 6-rings; 4 Mn2+ ions are in the sodalite cavity opposite to the double 6-rings; the remaining 20 Mn2+ ions are found at two non-equivalent threefold axes in the sodalite cavity and supercage with occupancies of 2 and 18, respectively. The 24 benzene molecules are found at two distinct positions within the supercages. Eighteen benzene molecules are found on the threefold axes in the supercages where each interacts facially with one of site-II Mn2+ ions (Mn2+-benzene center = ca. 2.53 A). The remaining six benzene molecules lie on the planes of the 12-rings where each is stabilized by multiple weak electrostatic and van der Waals interactions with framework oxygens.