Synthesis and structure of the medium-pore zeolite PST-35 with two interconnected cages of unusual orthorhombic shape

Abstract

The search for new zeolite structures and compositions remains important in synthetic materials science due to the high impact on developing new chemical technologies, as well as on improving existing ones. Herein we present the synthesis and structure of PST-35, a novel medium-pore germanosilicate (Si/Ge = 2.1–6.6) zeolite, achieved by combining the excess fluoride approach and the unique structure directing ability of Ge in the presence of 1,2,3-triethylimidazolium ions as an organic structure-directing agent. PST-35 contains a zig-zag 10-ring (4.6 × 6.7 Å) channel system constructed of strictly alternating large 28-hedral ([4⁸·5⁸·6⁸·8²·10²]) and smaller 18-hedral ([4⁶·5⁴·6⁴·8²·10²]) cages of anomalous orthorhombic shape. The PST-35 structure is built from the connection of pst-35 layers consisting of small 8-hedral ([4³·5⁴·6]) cages, previously unobserved zeolite building layers, through single 4-rings.