Tetrahydroxytetraindium(III) Nanoclusters, In4(OH)48+, in Air-Oxidized Fully In-Exchanged Zeolite Y (FAU, Si/Al = 1.69). Preparation and Crystal Structures of In−Y and In−Y[In4(OH)4]

The polyatomic tetrahydroxytetraindium(III) cations, In 4 (OH) 4 8+, have been synthesized in 94% of the sodalite cavities of zeolite Y (FAU, Si/Al = 1.69). In−Y ( | In 57.8 [In 5 ] 1.8 | [Si 121 Al 71 O 384 ]−FAU or In 66.8 −Y) was prepared by the oxidative solid state ion exchange (OSSIE) method from In 0 and single crystals of Tl−Y under anhydrous conditions at 623 K. One of these was exposed to the atmosphere and then zeolitically dry oxygen, both at 623 K, to give In−Y[In 4 (OH) 4 ] ( | In 7.6 [In 4 (OH) 4 ] 7.5 [In(OH) 2 ] 2.0 | [Si 121 Al 71 O 384 ]−FAU or In 39.6 (OH) 34.0 −Y). The structures of In−Y and In−Y[In 4 (OH) 4 ] were determined by single crystal crystallography with synchrotron X-radiation. They were refined in the space group Fd 3 m̅ ( a = 24.863(1) and 24.518(1) Å) with all unique data to the final error indices R 1 = 0.050 and 0.057 for the 1110 and 1037 reflections for which F o > 4σ( F o ), respectively. The In in In−Y is mostly In +; some In 5 7+ clusters are present in sodalite cavities. Upon oxidation in the presence of water, 41% of the In exited the zeolite. Most of the remainder formed In 4 (OH) 4 8+ clusters in the sodalite cavities of In−Y[In 4 (OH) 4 ]. In 4 (OH) 4 8+ is a tetrahedrally distorted In 4 O 4 cube with a hydrogen atom bound to each oxygen atom. In In 4 (OH) 4 8+, each In 3+ ion lies opposite a double 6-ring and is 6-coordinate octahedral with three bonds to OH − anions (2.245(4) Å) and three to framework oxygens (2.198(5) Å); each OH − ion is near a single 6-ring to which it hydrogen bonds. Small amounts of In(OH) 2 +, In 2+, and In + were also found.