"Pozice hlin\u00EDku v ZSM-5 zeolitu v kombinaci s 27Al 3Q MAS NMR spektroskopie a QM/MM v\u00FDpo\u010Dtu"@cs . "Pozice hlin\u00EDku v ZSM-5 zeolitu byly vy\u0161et\u0159ov\u00E1ny za pomoci 27Al 3Q MAS NMR spektroskopie a QM/MM v\u00FDpo\u010Dtu. Bylo zji\u0161t\u011Bno, \u017Ee obsazen\u00ED skelet\u00E1ln\u00EDch T pozic hlin\u00EDkem a koncentrace hlin\u00EDku v t\u011Bchto T pozic\u00EDch nen\u00ED ani n\u00E1hodn\u00E1 ani \u0159\u00EDzena jednoduch\u00FDm pravidlem. Oboj\u00ED z\u00E1vis\u00ED na podm\u00EDnk\u00E1ch synt\u00E9zy zeolitu. Nejm\u00E9n\u011B 12 z 24 rozli\u0161iteln\u00FDch skelet\u00E1ln\u00EDch T pozic v ZSM-5 jsou obsazeny hlin\u00EDkem ve zkouman\u00FDch vzorc\u00EDch ZSM-5. \u010C\u00E1ste\u010Dn\u00E1 identifikace t\u011Bchto Al pozic je mo\u017En\u00E1. Vypo\u010Dten\u00E9 27Al NMR st\u00EDn\u011Bn\u00ED bylo konvertov\u00E1no do 27Al isotropn\u00EDch chemick\u00FDch posun\u016F za vyu\u017Eit\u00ED experiment\u00E1ln\u00EDho isotropick\u00E9ho chemick\u00E9ho posunu 60.0 ppm vzta\u017Een\u00E9ho na vodn\u00ED roztok Al(NO3)(3) a p\u0159\u00EDslu\u0161n\u00E9ho vypo\u010Dten\u00E9ho NMR st\u00EDn\u011Bni 490.0 ppm pro k\u0159em\u00EDkem bohat\u00FD zeolit (Si/Al 38) chabazit jako sekund\u00E1rn\u00ED standard. Pozorovan\u00E9 27Al isotropick\u00E9 chemick\u00E9 posuny 50.0 and 54.7 ppm p\u0159\u00EDslu\u0161\u00ED Al atom\u016Fm v T20 a T6 pozic\u00EDch. P\u00E1r zm\u011B\u0159en\u00FDch isotropn\u00EDch chemick\u00FDch posun\u016F 52.9 and 53.7 ppm m\u016F\u017Ee b\u00FDt p\u0159i\u0159azen p\u00E1ru T4 a T8 pozic."@cs . "5"^^ . . "000263275400016" . . "RIV/61388955:_____/09:00322929!RIV09-AV0-61388955" . "[7A2BEC1CC915]" . . "Sklen\u00E1k, \u0160t\u011Bp\u00E1n" . "P(1ET400400413), P(GA203/06/1449), Z(AV0Z40400503)" . "G\u00E1bov\u00E1, Vendula" . "11"^^ . "8" . "Aluminium siting in the ZSM-5 framework by combination of high resolution Al-27 NMR and DFT/MM calculations" . "Physical Chemistry Chemical Physics" . . "Li, Chengbin" . . "GB - Spojen\u00E9 kr\u00E1lovstv\u00ED Velk\u00E9 Brit\u00E1nie a Severn\u00EDho Irska" . . . "MQ MAS NMR; approximate Coulomb potentials; ab-initio calculations"@en . "RIV/61388955:_____/09:00322929" . "Aluminium siting in the ZSM-5 framework by combination of high resolution Al-27 NMR and DFT/MM calculations"@en . . . "1463-9076" . "The Al siting in the ZSM-5 zeolite was investigated by Al-27 3Q MAS NMR spectroscopy and QM/MM calculations. It was found that the occupation of the framework T-sites by Al and the concentration of Al in these T-sites are neither random nor controlled by a simple rule. They both depend on the conditions of the zeolite synthesis. At least 12 out of the 24 distinguishable framework T-sites of ZSM-5 are occupied by Al in the set of the investigated zeolite samples. A partial identification of the Al sites is possible. The calculated 27 Al NMR shielding values were converted to 27 Al isotropic chemical shifts using the experimental isotropic chemical shift of 60.0 ppm referenced to the aqueous solution of Al(NO3)(3) and the corresponding calculated NMR shielding of 490.0 ppm of a silicon rich (Si/Al 38) chabazite structure zeolite as a secondary internal standard. The observed Al-27 isotropic chemical shifts of 50.0 and 54.7 ppm correspond to Al atoms in the T20 and T6 sites, resp." . "Pozice hlin\u00EDku v ZSM-5 zeolitu v kombinaci s 27Al 3Q MAS NMR spektroskopie a QM/MM v\u00FDpo\u010Dtu"@cs . . . . "302593" . . "Aluminium siting in the ZSM-5 framework by combination of high resolution Al-27 NMR and DFT/MM calculations"@en . "D\u011Bde\u010Dek, Ji\u0159\u00ED" . "Li, Chengbin" . "The Al siting in the ZSM-5 zeolite was investigated by Al-27 3Q MAS NMR spectroscopy and QM/MM calculations. It was found that the occupation of the framework T-sites by Al and the concentration of Al in these T-sites are neither random nor controlled by a simple rule. They both depend on the conditions of the zeolite synthesis. At least 12 out of the 24 distinguishable framework T-sites of ZSM-5 are occupied by Al in the set of the investigated zeolite samples. A partial identification of the Al sites is possible. The calculated 27 Al NMR shielding values were converted to 27 Al isotropic chemical shifts using the experimental isotropic chemical shift of 60.0 ppm referenced to the aqueous solution of Al(NO3)(3) and the corresponding calculated NMR shielding of 490.0 ppm of a silicon rich (Si/Al 38) chabazite structure zeolite as a secondary internal standard. The observed Al-27 isotropic chemical shifts of 50.0 and 54.7 ppm correspond to Al atoms in the T20 and T6 sites, resp."@en . "Sauer, J." . . . . . . "Wichterlov\u00E1, Blanka" . "7"^^ . "11" . "Aluminium siting in the ZSM-5 framework by combination of high resolution Al-27 NMR and DFT/MM calculations" . . . . "Sierka, M." .