Please use this identifier to cite or link to this item: doi:10.22028/D291-23953
Title: [TMPA]4[Si8O20] . 34H2O and [DDBO]4[Si8O20] . 32H2O are heteronetwork clathrates with 1,1,4,4-tetramethylpiperazinium (TMPA) and 1,4-dimethyl-1,4-diazoniabicyclo[2.2.2]octane (DDBO) guest cations
Author(s): Wiebcke, Michael
Emmer, Jörg
Felsche, Jürgen
Hoebbel, Dagobert
Engelhardt, Günter
Language: English
Year of Publication: 1994
OPUS Source: Zeitschrift für anorganische und allgemeine Chemie. - 620. 1994, S. 757-765
SWD key words: Kristallisation
DDC notations: 540 Chemistry
Publikation type: Journal Article
Abstract: [TMPA]4[Si8O20] · 34 H2O (1) and [DDBO]4[Si8O20] · 32 H2O (2) have been prepared by crystallization from aqueous solutions of the respective quaternary alkylammonium hydroxide and SiO2. The crystal structures have been determined by single-crystal X-ray diffraction. 1: Monoclinic, a = 16.056(2), b = 22.086(6), c = 22.701(2) Å, = 90.57(1)° (T = 210 K), space group C2/c, Z = 4. 2: Monoclinic, a = 14.828(9), b = 20.201(7), c = 15.519(5) Å, = 124.13(4)° (T = 255 K), space group P21/c, Z = 2. The polyhydrates are structurally related host-guest compounds with three-dimensional host frameworks composed of oligomeric [Si8O20]8- anions and H2O molecules which are linked via hydrogen bonds. The silicate anions possess a cube-shaped double four-ring structure and a characteristic local environment formed by 24 H2O molecules and six cations (TMPA, [C8H20N2]2+, or DDBO, [C8H18N2]2+). The cations themselves reside as guest species in large, irregular, cage-like voids. Studies employing 29Si NMR spectroscopy and the trimethylsilylation method have revealed that the saturated aqueous solutions of 1 and 2 contain high proportions of double four-ring silicate anions. Such anions are also abundant species in the saturated solution of the heteronetwork clathrate [DMPI]6[Si8O18(OH)2] · 48.5 H2O (3) with 1,1-dimethylpiperidinium (DMPI, [C7H16N]+) guest cations.
Link to this record: urn:nbn:de:bsz:291-scidok-19578
Date of registration: 22-Dec-2008
Faculty: SE - Sonstige Einrichtungen
Department: SE - INM Leibniz-Institut für Neue Materialien
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