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Abstract: Zeolite losod prepared with tetrabutylammonium hydroxide was applied as matrix for sulfur anion-radicals thermally generated from precursors (elemental sulfur and alkalis or alkaline oligosulfides). We hoped that large los cages could favor formation and stabilization of big radicals (e.g. red ). The products with maintained LOS structure, however, always showed light green or blue coloration (due to and radicals) and bigger radicals never were detected (EPR). It is likely that the sulfur radicals in the products occupy rather eri cages in LOS structure, whereas the large los cages do not accommodate any radicals, because several of them could stay there and subsequently recombine to ordinary oligosulfides. Some reduction of los cage size by means of Cs or K cations resulted in a degradation of LOS structure. Introduction of sulfur compounds already during the losod crystallization disturbed formation of LOS structure. [Copyright &y& Elsevier]

Abstract: Colored products have been obtained by thermal treatment of erionite mixed with elemental sulfur and alkalis (Na2CO3 or K2CO3). Synthesis at lower temperature (500°C) resulted in forming colored materials with preserved ERI structure (particularly with potassium cations), whereas the treatment of highly alkaline mixtures at high temperature (800°C) caused re-crystallization to SOD (when Na was used) or to unknown structures (with K). The ESR spectra of the products with preserved original ERI structure recorded at room temperature show two signals, one with g =2.030 and another with g tensor value either 2.045 (for sodium containing samples) or 2.005 (for the potassium bearing products). The latter signal could be considered as a reflection of radicals immobilized in small ε-cages, but it is more likely that it presents anisotropic component of the radical spectrum. The spectra measured at 77K show anisotropy indicating three values of orthorhombic g-tensor, which is typical of radical, although the values vary for particular samples. [Copyright &y& Elsevier]

Abstract: The colored products analogous to ultramarine have been obtained by thermal treatment (500–800°C) of cancrinite mixed with elemental sulfur and alkalis. The samples obtained at 500°C maintain the original structure of cancrinite, while heating of the mixture at 800°C resulted in zeolite structure transformation towards SOD in the case of mixture containing Na+ cations and to kaliophilite or unknown structures, when K+ or Li+ were applied as alkali sources. Encapsulation of sulfur species inside the cancrinite cages does not result in the generation of another radicals but , which is reflected in the ESR spectra resembling those embedded in sodalite cages. [Copyright &y& Elsevier]

Abstract: MOF-5 and ZIF-8 were used for the first time as matrices for pigments containing entrapped dmit. The chromophore was introduced either by impregnation or by its synthesis from CS2 inside the matrices. Pigments with ZIF-8 resisted washing and maintained the structure, while these with MOF-5 underwent structure altering or amorphization. [Copyright &y& Elsevier]

Imidazole (Im) introduced into the channels of H-MFI zeolites (with diverse framework Si/Al) shows remarkably enhanced proton conductivity in a broad temperature range (303–393 K), which increased with Im loading. Some conductivity raise is already noticed after its introduction into slilicalite-1 (i.e. SiO 2) due to escalated Im dispersion and subsequently enhanced mobility inside the channels. The increase, however, becomes much more spectacular for the Im composites based on H-forms of aluminosilicate MFI zeolite matrices. It results from additional beneficial interaction of the guest Im with the zeolite acid sites, particularly OH groups, acting as additional proton carriers. Nevertheless, there is no straight correlation between the number of acid sites and the proton conductivity. It seems that the strong Lewis acid sites, contrary to Broensted centers, hinder the conduction, because of firm bonding the Im molecules and reducing their motion. Thus, both kind of sites compete with each other. The highest conduction noticed for the composites based on the H-zeolite with Si/Al = 50 results not so much from pronounced contribution of Broensted centers, but rather from the small number of Lewis sites which are relatively weak. Both Grotthuss and vehicle conductivity modes could be considered. Image 1 • Anhydrous proton conductors. • Imidazole entrapped in H-zeolites MFI with various Si/Al. • Impact of acid sites on composite conductivity. [ABSTRACT FROM AUTHOR]

Abstract Imidazole entrapped in H-forms of FAU zeolites with various Si/Al ratios (1, 4, 40) exhibit high and stable proton conductivity (up to ∼10−3 S/cm) in a broad range of temperatures (293–393 K). The conductivity increases with temperature and imidazole loading. The number and strength of zeolite acid sites (resulting from various Si/Al) influence markedly the conductivity of composites. The samples based on zeolites with low Si/Al (1) show markedly higher conduction than these supported on the matrix with medium Si/Al (4), regardless of very similar number of the acid OH groups. The strong acid OH groups in zeolite with Si/Al = 4 result in protonation and immobilization of adsorbed imidazole, which reduce their mobility and subsequently the conduction. The low siliceous with weaker acid sites protonate imidazole and form a chain of H-bonds effective in proton propagation. Almost neutral high silica matrix provides a high mobility of dispersed imidazole, due to weak mutual interaction. The overloaded samples indicate a phase transition effect at elevated temperature due to melting of extra-matrix imidazole, which is reflected in dramatic increase in conductivity. Graphical abstract Image 1 Highlights • Proton conductivity of imidazole entrapped in H-forms of faujasites. • Role of imidazole loading, phase transition at high temperature. • Influence of Si/Al on efficiency and mechanism of conduction. [ABSTRACT FROM AUTHOR]

Fluorescein was entrapped inside FAU type zeolite (Y) by generating it from resorcinol and phthalic anhydride. Prior to the formation of fluorescein, zeolite Y was modified with various cations (H, Zn, Ce, Na, K). The modified zeolite acted as catalysts for the fluorescein Friedel–Crafts reaction synthesis, while at the same time it played a role of matrix for the stabilization and homogeneous dispersion of the guest molecules. The nature of the different cations influenced the content of fluorescein generated in the zeolite, and favoured the formation of some dye isomers (i.e. anion, dianion, cation or transition metal complex). The contribution of different fluorescein derivatives in the products was reflected in their absorption and fluorescence properties. The H-, Ce-, and Zn- containing Y zeolites revealed the highest content of fluorescein due to their distinct acid active sites. The composites with H- and ZnY zeolites indicated much higher fluorescence than that of the pristine fluorescein. Moreover, fluorescein in zeolite Y matrices did not show any photobleaching under continuous illumination (λ = 730 nm, in a two-photon experiment for 180 s), which suggests that these materials could be used for biomedical applications. [ABSTRACT FROM AUTHOR]