ISSN:
1573-1111
Keywords:
Clathrasil
;
nonasil
;
synthesis
;
crystal structure
;
porous silica
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Nonasils-[4158], 88SiO2·8M8·8M9·4M20, have been synthesized with 2-methylpyrrolidine, hexamethyleneimine, 2-(aminomethyl)-tetrahydrofuran, 1,2-diaminocyclohexane, 2-methylpiperidine, 2-methylpiperazine, 1-aminobutane, 2-aminobutane, and 2-aminopentane as guest molecules, M20. The samples have been prepared from aqueous silicate solutions which were sealed in silica tubes and heated at about 200°C for several weeks. These clathrasils crystallize in space groupFmmm. For the nonasil with 2-aminopentane as the guest molecule and the unit cell dimensionsa o=22.232(6) Å,b 0=15.058(4) Å, andc o=13.627(4) Å, the structure has been refined using 550 non-equivalent single crystal reflexions to a reliability factorR w =0.125. The 3-dimensional 4-connected silica host framework has three types of cage-like voids, [5464], [4158], and [58612], the latter housing the structure-controlling guest molecules, M20. The non-spherical shape of the guest molecules is the most important factor for the formation of nonasils-[4158]. On heating nonasils-[4158] up to 950°C the organic guest species are driven out and the pure silica form of nonasil is obtained.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00656161
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