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

The single-crystal structure of a mesitylene sorption complex of fully dehydrated fully Mn2+-exchanged zeolite Y, |Mn37.5(C9H12)15|[Si117Al75O384]-FAU, has been determined by single-crystal synchrotron X-ray diffraction techniques in the space group Fd  3¯m at 100(1) K. A fully dehydrated fully Mn2+-exchanged zeolite Y crystal (|Mn37.5|[Si117Al75O384]-FAU, Si/Al = 1.56) was treated with zeolitically dried mesitylene at 297(1) K for 3 days. The structure of the resulting dark-brown crystal was refined using all intensities to the final error indices (using the 570 reflections for which Fo > 4σ(Fo)) of R1 = 0.063 and wR2 = 0.151. In this structure, 37.5 Mn2+ ions per unit cell are found at four crystallographic positions: 14.5 are at the centers of the double 6-rings (site I) and three are in the sodalite cavity opposite the double 6-rings (site I′). The remaining 20 are found at two nonequivalent sites II, near 6-rings in the supercage with occupancies of 5 and 15, respectively. Fifteen mesitylene molecules per unit cell lie on threefold axes where these interact facially with the 15 Mn2+ ions at the first site II (Mn2+-mesitylene center = ca. 2.65 Å). Of the three hydrogen atoms per methyl group, one is calculated to be 2.14 Å from a framework oxygen and another one is 2.48 Å from another framework oxygen atom. Mesitylene appears to be slightly distorted in the same way.

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► Mesitylene sorption complex of Mn37.5-Y zeolite was studied crystallographically.
► There are 37.5 Mn2+ ions at four crystallographic positions of FAU type zeolite.
► Fifteen mesitylenes interact facially with 15 ions at site II.
► Two Hydrogens per methyl group are close and interact with framework oxygens.