TY  - JOUR
A1  - Goebel, Ronald
A1  - Hesemann, Peter
A1  - Friedrich, Alwin
A1  - Rothe, Regina
A1  - Schlaad, Helmut
A1  - Taubert, Andreas
T1  - Modular thiol-ene chemistry approach towards mesoporous silica monoliths with organically modified pore walls
JF  - Chemistry - a European journal
N2  - The surface modification of mesoporous silica monoliths through thiol-ene chemistry is reported. First, mesoporous silica monoliths with vinyl, allyl, and thiol groups were synthesized through a sol-gel hydrolysis-poly-condensation reaction from tetramethyl orthosilicate (TMOS) and vinyltriethoxysilane, allyltriethoxysilane, and (3-mercaptopropyl) trimethoxysilane, respectively. By variation of the molar ratio of the comonomers TMOS and functional silane, mesoporous silica objects containing different amounts of vinyl, allyl, and thiol groups were obtained. These intermediates can subsequently be derivatized through radical photoaddition reactions either with a thiol or an olefin, depending on the initial pore wall functionality, to yield silica monoliths with different pore-wall chemistries. Nitrogen sorption, small-angle X-ray scattering, solid-state NMR spectroscopy, elemental analysis, thermogravimetric analysis, and redox titration demonstrate that the synthetic pathway influences the morphology and pore characteristics of the resulting monoliths and also plays a significant role in the efficiency of functionalization. Moreover, the different reactivity of the vinyl and allyl groups on the pore wall affects the addition reaction, and hence, the degree of the pore-wall functionalization. This report demonstrates that thiol-ene photoaddition reactions are a versatile platform for the generation of a large variety of organically modified silica monoliths with different pore surfaces.
KW  - mesoporous materials
KW  - photochemistry
KW  - sol-gel processes
KW  - surface chemistry
Y1  - 2014
U6  - https://doi.org/10.1002/chem.201403982
SN  - 0947-6539
SN  - 1521-3765
VL  - 20
IS  - 52
SP  - 17579
EP  - 17589
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Goebel, Ronald
A1  - Hesemann, Peter
A1  - Weber, Jens
A1  - Moeller, Eléonore
A1  - Friedrich, Alwin
A1  - Beuermann, Sabine
A1  - Taubert, Andreas
T1  - Surprisingly high, bulk liquid-like mobility of silica-confined ionic liquids
N2  - Mesoporous silica monoliths were prepared by the sol - gel technique and. lled with 1-ethyl-3-methyl imidazolium [Emim]-X (X = dicyanamide [N(CN)(2)], ethyl sulfate [EtSO4], thiocyanate [SCN], and triflate [TfO]) ionic liquids (ILs) using a methanol-IL exchange technique. The structure and behavior of the ILs inside the silica monoliths were studied using X-ray scattering, nitrogen sorption, IR spectroscopy, solid-state NMR, and thermal analysis. DSC finds shifts in both the glass transition temperature and melting points (where applicable) of the ILs. Glass transition and melting occur well below room temperature. There is thus no conflict with the NMR and IR data, which show that the ILs are as mobile at room temperature as the bulk (not confined) ILs. The very narrow line widths of the NMR spectra suggest that the ILs in our materials have the highest mobility reported for confined ILs so far. As a result, our data suggest that it is possible to generate IL/silica hybrid materials (ionogels) with bulk-like properties of the IL. This could be interesting for applications in, e.g., the solar cell or membrane fields.
Y1  - 2009
UR  - http://xlink.rsc.org/jumptojournal.cfm?journal_code=CP
U6  - https://doi.org/10.1039/B821833a
SN  - 1463-9076
ER  -