Luis Gómez-Hortigüela, Miguel A. Camblor, Peng Lu, Alvaro Mayoral, Yaping Zhang, Ministerio de Economía y Competitividad (España), National Natural Science Foundation of China, Gómez-Hortigüela Sainz, Luis [0000-0002-4960-8709], Camblor, Miguel Ángel [0000-0001-9591-3432], Gómez-Hortigüela Sainz, Luis, and Camblor, Miguel Ángel
[EN] Introduction of small molar fractions of Ge in a synthesis system otherwise yielding the monodimensional large-pore zeolite MTW produced three 3D large-pore materials as the Ge fraction increased: *BEA, HPM-8, and HPM-7. HPM-8 is a zeolite consisting of an intergrowth of polymorphs D and E of the zeolite Beta family with a large predominance (>80%) of polymorph D, according to DIFFaX simulations and high-resolution scanning transmission electron microscopy analysis. After calcination, HPM-8 becomes remarkably stable upon contact with ambient air. HPM-7 likely possesses the POS topology, which is related to polymorph C. The density of double 4-ring (D4R) units in the crystallized materials increases from *BEA to HPM-8 to HPM-7, that is, as the Ge fraction increases. Interestingly, molecular mechanics show that in both HPM-7 and HPM-8, the organic dications prefer to site with their imidazolium rings in close contact with the D4R units as a consequence of a stronger confinement in this position. Indeed, the structure-directing role of these long dications can be explained as a consequence of the appropriate distance match between adjacent D4R units in both zeolite frameworks (and hence the negative charges associated with the occluded fluoride) and the imidazolium rings of these organic dications (and hence the positive charges), which is dictated by the length of the alkyl spacers, thus driving the crystallization pathway toward these particular germanosilicate zeolites., Ministry of Science, Innovation and Universities (projects MAT2016-77496-R and MAT2015-71117-R) and the National Natural Science Foundation of China (NSFC-21850410448, NSFC- 21835002). P.L. is grateful to the China Scholarship Council (CSC) for a fellowship and to the Dalian Institute of Chemical Physics for permission to leave. A.M. and Y.Z. acknowledge The Centre for High-resolution Electron Microscopy (CℏEM), supported by SPST of ShanghaiTech University under contract No. EM02161943. The authors are also indebted to L.A. Villaescusa (Valencia) for helpful comments and suggestions. Centro Técnico Informático-CSIC is acknowledged for running the calculations, and Biovia for providing the computational software.