Thermal crystal phase transition in zeolitic imidazolate frameworks induced by nanosizing the crystal

Abstract

An unusual crystal phase transition was demonstrated in a zeolitic imidazolate framework with a rigid coordination network. Differential scanning calorimetry and powder X-ray diffraction revealed that the nanosizing crystal structure...

Metal–organic framework adhesives with exceptionally high heat resistance

“…These processes are also shown schematically in Figure 5 . The above results are consistent with the phase transition point from ZIF-67 sod to ZIF-67 qtz that reportedly occurs at ∼280°C and the thermal decomposition temperature at ∼400°C [ 16 ]. In addition, these results indicate that the ZIF-67 qtz phase is more easily pyrolyzed in air than in nitrogen, which is consistent with the TG-DTA results discussed above (Figure S5).…”

Formation of new crystalline qtz-[Zn(mIm)2] polymorph from amorphous ZIF-8

“…27 In an incredibly recent study, a material exhibiting the qtz topology was prepared by heating a sample of nanosized (20 nm) crystalline SOD-[Zn(mIm) 2 ] . 28 However, in this case, the authors were not able to obtain cell parameters, or atomic positions within this previously unknown structure. The qtz-[Zn(mIm) 2 ] has some differences to other previously published qtz topology ZIFs, qtz-[M(eIm) 2 ] where M = Zn,29 Fe and Co, 27 and [Fe(mIm) 2 ].…”

“…27 In an incredibly recent study, a material exhibiting the qtz topology was prepared by heating a sample of nanosized (20 nm) crystalline SOD-[Zn(mIm) 2 ]. 28 However, in this case, the authors were not able to obtain cell parameters, or atomic positions within this previously unknown structure. Gas sorption experiments were performed on ZIF-8, a m ZIF-8, and qtz-[Zn(mIm) 2 ], to investigate their porosity (Fig.…”

Direct observation of crystal degradation behaviour in porous crystals under low-dose electron diffraction conditions

“…Nanosized MOF crystals were prepared to maintain high crystallinity by previously reported synthetic procedures. 20,21 According to this method, 30 nm-sized ZIF-8 nanocrystals, which consist of a Zinc (II) ion and 2-methylimidazolate (2-MIm), were prepared using an appropriate combination of reaction temperature/ reaction solvent/additives (Fig. 1a).…”

“…Next, the electron beam resistance of the MOF crystals with different frameworks and compositions was evaluated to identify intrinsic structural factors in electron beam damage. Here, various nanosized MOFs were prepared, 20,21 including ZIF-67 consisting of cobalt (II) ions and 2-MIm, MAF-6 consisting of Zinc (II) ions and 2-ethylimidazole, Ti-doped UiO-66 composed of terephthalic acid and zirconium clusters partially replaced by Titanium (IV) ions, UiO-66-NH 2 consisting of a zirconium cluster and 2-aminoterephthalic acid, UiO-66-Br 2 consisting of a zirconium cluster and 2,5-dibromoterephthalic acid, UiO-67 consisting of a zirconium cluster and 4,4 0 -biphenyldicarboxylic acid, and ZIF-7 consisting of Zinc (II) ions and benzimidazole (Table S1, ESI †). Transmission electron microscope (TEM) images reveal that the crystal size of all MOFs is about 50 nm, as shown in Fig.…”