Precursors 3-aminopropyltriethoxysilane

The formulation of the ORMOSIL precursor is chosen in the light of screening experiments (Figure 6.13). For the recognition of ovalbumin, for example, the precursor is a 55 mol% TEOS, 2 mol% 3-aminopro-pyltriethoxysilane (APTES), 3 mol% n-octyItrimethoxysi 1 ane (C8-TMOS) and 40 mol% bis(2-hydroxyethyl)aminopropyltriethoxysilane (HAPTS) mixture. The resulting microarray sensor exhibits analytical... 

Organic ligands added to sol solutions can be used to control NC growth and size dispersities. " This approach, analogous to the method described for metal NCs in Section 2.1, employs bifunctional linkers to tether metal salts to the sol-gel network to improve the homogeneity of the sample. Silica precursors mixed with 3-aminopropyltriethoxysilane (APTES) and cadmium nitrate were allowed to gel. Following oxidative treatments, the resulting CdO particles were converted to CdS upon exposure to H2S, as shown in equation (4). The size distribution of particles was much narrower under these conditions than when APTES was omitted from the reaction. 

The precursor compound, phosphornitrilic chloride trimer, reacts with nitrogen and oxygen nucleophiles to form stable products [10]. Reaction of the trimeric phosphazene chloride with nitrogen nucleophiles, such as 3-aminopropyltriethoxysilane, facilitates the introduction of the silane component in a single step resulting in the modified compounds 13 and 14 in yields of about 90 % (Eq. 5 Table 3)... 

Table 1. Average metal particle diameters (from XRD) for some metal precursor/silane combinations [AEAPTS = 3-(2-aminoethylamino)propyltriethoxysilane, APS = aminopropyltriethoxysilane, TAS = (3-trimethoxy-silylpropyl)-diethylentriamine)].

As already underlined in the first part of the text, the mesoporosity can be controlled through the sol-gel process conditions, for example, when a two-step catalysis is applied to standard alkoxides such as TMOS [36, 82, 103]. If these simple tetia-alkoxides are mixed with a more exotic functionalized Si precursor, differences in the hydrolysis and condensation rates of the two precursors may drastically influence the final texture of the material. For example, when the functionalized precursor carries basic moieties such as an amine in 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS), 3-aminopropyltriethoxysilane (AES), or 3-aminopropyltrimethoxysilane (AMS), these functionalized precursors can act as nucleation centers for condensation and can lead to generation of large macropores [104, 105]. 

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