title: High-silica zeolite SSZ-61 with dumbbell-shaped extra-large-pore channels.
abstract: The synthesis of the high-silica zeolite SSZ-61 using a particularly bulky polycyclic structure-directing agent and the subsequent elucidation of its unusual framework structure with extra-large dumbbell-shaped pore openings are described. By using information derived from a variety of X-ray powder diffraction and electron microscopy techniques, the complex framework structure, with 20 Si atoms in the asymmetric unit, could be determined and the full structure refined. The Si atoms at the waist of the dumbbell are only three-connected and are bonded to terminal O atoms pointing into the channel. Unlike the six previously reported extra-large-pore zeolites, SSZ-61 contains no heteroatoms in the framework and can be calcined easily. This, coupled with the possibility of inserting a catalytically active center in the channel between the terminal O atoms in place of H(+), afford SSZ-61 intriguing potential for catalytic applications.
authors.affiliation: Laboratory of Crystallography, ETH Zurich, 8093 Zurich (Switzerland).
authors.forename: Stef
authors.initials: S
authors.lastname: Smeets
authors.forename: Dan
authors.initials: D
authors.lastname: Xie
authors.forename: Christian
authors.initials: C
authors.lastname: Baerlocher
authors.forename: Lynne B
authors.initials: LB
authors.lastname: McCusker
authors.forename: Wei
authors.initials: W
authors.lastname: Wan
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zou
authors.forename: Stacey I
authors.initials: SI
authors.lastname: Zones
keywords: X-ray diffraction; electron microscopy; microporous materials; structure elucidation; zeolites