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An organic cation lacking specificity in its structure-directing action offers the possibility, through the screening of other structure-directing parameters, to synthesize a variety of zeolites. In this work we show that the organic structure-directing agent 2-isopropyl-1,3-dimethylimidazolium (2iPr13DMI) can produce up to seven different zeolite phases depending on water concentration, the presence of inorganic impurities, crystallization temperature and time, and germanium molar fraction. The obtained phases are very different in terms of pore system, connectivity of the zeolite structure and structural units. At the pure SiO2 side, ZSM-12 and SSZ-35 dominate, with ZSM-12 being favored by the presence of potassium impurities and by less concentrated conditions. The introduction of Ge at low levels favors SSZ-35 over ZSM-12 and as the Ge fraction increases it successively affords CSV, -CLO and two distinct UOS zeolites, HPM-11 and HPM-6. These two zeolites have the same topology but distinct chemical compositions and display powder X-ray diffraction patterns that are much different from each other and from that of as-synthesized IM-16 (UOS reference material). They also show different symmetry at 96 K. Rietveld refinements of the three as-made UOS materials mentioned are provided. HPM-6 and HPM-11 are produced in distinct, non-adjacent crystallization fields. The frequent cocrystallization of the chiral STW zeolite, however, did not afford its synthesis as a pure phase. Molecular mechanics simulations of the location of the organic cation and host–guest interactions fail to explain the observed trends, but also considering the intrinsic stability of the zeolites and the effect of germanium help to rationalize the results. The study is completed by DFT calculations of the NMR chemical shifts of 13C in UOS (helping to understand splittings in the spectrum) and 19F in CSV (supporting the location of fluoride inside the new [4452], which is an incomplete double 4-ring). [ABSTRACT FROM AUTHOR]

HPM‐14 is a new extra‐large pore zeolite synthesized using imidazolium‐based organic structure‐directing agents (SDAs), fluoride anions, and germanium and silicon as tetrahedral components of the framework. Owing to the presence of stacking disorder, the structure elucidation of HPM‐14 was challenging, and different techniques were necessary to clarify the details of the structure and to understand the nature of the disorder. The structure has been solved by three‐dimensional electron‐diffraction technique (3D ED) and consists of an intergrowth of two polymorphs possessing a three‐dimensional channel system, including an extra‐large pore opened through windows made up of sixteen tetrahedral atoms (16‐membered ring, 16MR) as well as two additional sets of odd‐membered (9MR) and small (8MR) pores. The intergrowth has been studied by scanning transmission electron microscopy (Cs‐STEM) and powder X‐ray diffraction simulations (DIFFaX), which show a large predominance of the monoclinic polymorph A. [ABSTRACT FROM AUTHOR]

IDM‐1 is a new silica zeolite with an ordered and well‐defined framework constructed by alternating pentasil layers and interrupted layers, giving rise to an intersecting system of straight medium pores and undulating extra‐large lobed pores. This unique structure was solved by rotation electron diffraction and refined against synchrotron powder X‐ray diffraction data. Despite the presence of both Si(OSi)3(OH) and Si(OSi)2(OH)2 sites, this new zeolite presents high thermal stability, withstanding calcination even to 1000 °C. The location of defects at specific sites of the structure results in alternating hydrophobic SiO2 and hydrophilic SiO(2−x)(OH)2x intracrystalline regions. This peculiar combination of intersecting medium and extra‐large pores and alternating regions of different chemical character may provide this zeolite with unique catalytic properties. [ABSTRACT FROM AUTHOR]

HPM-7, a germanosilicate synthesized using long imidazolium-based dications with two different linkers, is shown to possess the POS topology, although disorder may exist but it is very difficult to discern. First, three simple ordered polymorphs (POS-A to POS-C) with very similar energies and structural motifs could give rise to intergrowths that would be very difficult to recognize by powder X-ray diffraction, according to DIFFaX simulations. Another four structures (POS-D to POS-G) can be derived from POS by changing the orientation of two single four rings within the structure, possibly providing an additional source of disorder. While 3D EDT strongly suggests that HPM-7 basically possesses the POS-A (i.e. POS) topology, a detailed HR-STEM study demonstrates the rare existence of some disorder compatible with the polymorph POS-D. The general avoidance of polymorphs with very similar structural motifs and comparable energies points to a rather specific structure-direction by the organic dications used. [ABSTRACT FROM AUTHOR]