Metamorphic Channels in Periodic Mesoporous Methylenesilica

Abstract

Bridging methylene groups are transformed into terminal methyl groups when periodic mesoporous methylenesilicas, prepared for the first time by surfactant‐templated synthesis, are subjected to controlled thermal treatment at 350–600°C. The methylene groups integrated “inside the channel walls” transform smoothly to methyl groups suspended “within the channel spaces” (shown schematically).

Large Pore Methylene-Bridged Periodic Mesoporous Organosilicas: Synthesis, Bifunctionalization and Their Use as Nanotemplates

“…This result confirms the presence of the methylene groups inside the frameworks of PMO-Me. 11,25 The small signal at 70.5 ppm arises from the ethylene oxide block of the P123 surfactant. 26 The peak at 57.9 ppm is attributed to the carbons from the surface ethoxy groups (Si-OCH 2 CH 3 ), which form during solvent extraction in acidic ethanol solutions.…”

“…Thus, PMOs contain a uniform distribution of organic and inorganic moieties at the molecular level within their frameworks. To date, a series of small mesopore PMOs have been prepared under basic conditions, [11][12][13][14][15][16] and large pore PMOs have been synthesized under acidic conditions. 17 Bifunctionalized PMOs have also been fabricated by the cocondensation of bridged silsesquioxanes and silicon coupling agents.…”

Modification of Mesoporous Silicates for Immobilization of Enzymes

“…The adsorption of His-tagged proteins onto Ni(II) or Co(II) functionalised surfaces has been demonstrated previously [25,26,44]. Cho et al (1,4,8,11-tetraazacyclotetradecane) is a widely used 14-membered tetra-amine macrocycle.…”

“…PMOs may be synthesised under acidic or basic conditions. PMOs were initially prepared using ionic surfactants such as cetyltrimethylammonium bromide [24][25][26] and B50-6600 (EO 39 PO 47 EO 39 ) [27]. As an example of the stability of these materials, PMO-SBA-15 synthesized from P123 in acidic media [28], was stable for 60 days when placed in boiling water.…”

Effect of the C-bridge length on the ultraviolet-resistance of oxycarbosilane low-k films

“…33 Nevertheless, contribution from Si(CH 3 ) x is not excluded due to conversion of the alkylene groups into alkyl. 34,35 Furthermore, the region below 3000 cm À1 contains the signals associated with the C-H stretch vibrations in -CH 3 (2975 and 2905 cm À1 ) and -CH 2 (2930 and 2880 cm À1 ) units. The CH 3 groups in MeLK are bonded to the matrix as Si-CH 3 while the CH 2 signal is mainly attributed to the remaining template.…”