Surface Functionalization of Silica by Si–H Activation of Hydrosilanes

Abstract

Inspired by homogeneous borane catalysts that promote Si-H bond activation, we herein describe an innovative method for surface modification of silica using hydrosilanes as the modification precursor and tris(pentafluorophenyl)borane (B(C6F5)3) as the catalyst. Since the surface modification reaction between surface silanol and hydrosilane is dehydrogenative, progress and termination of the reaction can easily be confirmed by the naked eye. This new metal-free process can be performed at room temperature and requires less than 5 min to complete. Hydrosilanes bearing a range of functional groups, including alcohols and carboxylic acids, have been immobilized by this method. An excellent preservation of delicate functional groups, which are otherwise decomposed in other methods, makes this methodology appealing for versatile applications.

Facile Synthesis of a Luminescent Material, PAN@{SiO2}n, Having a Simultaneous Binding Capacity of High and Low Oxidation States: HOMO and LUMO, Quantum-mechanical Descriptor of Break-through Capacity

“…[11][12][13][14][15][16][17][18][19][20][21] The composition ({Si A new kind of reaction occurs, whereby the material uniquely binds two different metal centers (Cd(II) and Tl(I)) in their HLOS simultaneously at its respective HOMO and LUMO, residing at two different spatial locations (Scheme 2a). Thereby, it differs from the existing mode of reaction reported until now (Scheme 2b).…”

“…11,12 Thus, functionalized SG (FSG) with greater selectivity is a necessity. 7,13,14 It is obtained by either coating a high molecular mass liquid cation exchanger (HMMLCE) on silanised SG, 9,13 or by the formation of covalent siloxanes (Si-O-Si) (denoted as grafting) 15,16 through a suitable grafting component (viz. 3-aminopropyltrimethoxysilane, 11 3-mercaptopropyltrimethoxy-silane, 17 allyl-, 18 methallyl-, 19 vinylsilane, 20 isocyanosilane 21 hydrosilanes 16 etc.).…”

“…15,16 However, the cross-linking activity of the bridging component increases the size of FSG, and its surface activity was turned down to a moderate level. 11 Moreover, such a type of siloxane synthesis either required complicated steps under stringent reaction conditions (refluxing, 24 -90 h; starring; very high or low temperature; repetitive filtrations; inert atmosphere; vacuum; costly and hazardous chemicals), 8,11,17,22 or needs very strong Lewis acids (like B(C6F5)3 in the hydrosilylation reaction) 16 or transition/noble metals [18][19][20] as a catalyst. Such extractors having HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) at the same spatial location are able to bind metals either at high or low oxidation states (OS) using their HOMO and LUMO operative on the same metal center.…”

A New Route for Preparation of Hydrophobic Silica Nanoparticles Using a Mixture of Poly(dimethylsiloxane) and Diethyl Carbonate

“…Also, chemically modified silicas are widely used as an anti-settling and anti-sagging agent of pigments, and in epoxy coatings, respectively. Organophilization of silica surfaces can be performed using various traditional kinds of modifying agents such as alkoxy-, halo-, aminosilanes and organosilazanes [1][2][3][4][5][6][7][8]. However, due to high reactivity and moisture sensitivity of above-mentioned modifying agents, purification is often critical for these hydrolyzable precursors.…”

Versatile Double-Cross-Linking Approach to Transparent, Machinable, Supercompressible, Highly Bendable Aerogel Thermal Superinsulators

“…Besides, as presented in Figure 2c, the bands located at 1406 cm −1 and 1456 cm −1 are ascribed to the symmetric deformation and bending of C-H bonds, respectively, while the bands located at 2865 cm −1 , 2923 cm −1 , and 2964 cm −1 are attributed to the stretching of C-H bonds. [37][38][39] These bands mainly result from the aliphatic hydrocarbon chains of PVPSQ and PAPSQ aerogels, and the hydrocarbon chains plus methyl groups of PVPMS and PAPMS aerogels. It is noteworthy that, unlike PVPSQ and PAPSQ aerogels, the PVPMS and PAPMS aerogels show intense absorption bands at 780 cm −1 , ~818 cm −1 and 1260 cm −1 corresponding to the asymmetric stretching of Si-C bonds, rocking of CH3 and asymmetric deformation of C-H bonds, 37 respectively, indicating the methyl-rich polymethylsiloxane structure of PVPMS and This is the original manuscript before revision.…”