Silicates, organically modified

Another electro-oxidation example catalyzed by bimetallic nanoparticles was reported by D Souza and Sam-path [206]. They prepared Pd-core/Pt-shell bimetallic nanoparticles in a single step in the form of sols, gels, and monoliths, using organically modified silicates, and demonstrated electrocatalysis of ascorbic acid oxidation. Steady-state response of Pd/Pt bimetallic nanoparticles-modified glassy-carbon electrode for ascorbic acid oxidation was rather fast, of the order of a few tens of seconds, and the linearity was observed between the electric current and the concentration of ascorbic acid. 

Organically Modified Silicates as Inorganic-Organic Polymers... 

Precursors are generally ORMOSILs, that is, organically modified silicates. The procedure for metal catalysts is similar to that for lipases, apart from the use of an argon atmosphere. More details of these procedures can be found in the literature [26]. 

Tsuru, K., Ohtsuki, C., Osaka, A., Iwamoto, T. and Mackenzie, J.D. (1997) Bioactivity of sol-gel derived organically modified silicates, Parti In vitro examination. Journal of Materials Science-Materials in Medicine, 8, 157-161. 

Hu, Y. and Mackenzie J.D. (1992) Rubber-like elasticity of organically modified silicates. Journal of Materials Science, 27, 4415 1420. 

Various polymer matrices can be used as solid support into which pH indicator dye can be immobilized (cellulose, PVA, PVC). R. Makote and M.M. Collinson shows that also organically modified silicate films can be used for stable pH sensors37. 

Makote R., Collinson M.M., Organically modified silicate films for stable pH sensors, Analytica Chimica Acta 1999 394 195-200. 

M.M. Collinson, Recent trends in analytical applications of organically modified silicate materials. 

Remarkably analogous findings have been established in recent years from the study of a number of catalytic species entrapped in sol-gel glasses. In particular, molecular entrapment in hybrid organic-inorganic ceramic matrices such as organically modified silicates resulted in... 

Along with these recent technologies, sol-gel entrapped catalysts made of organically modified silicates (ORMOSIL) doped with one or... 

Figure 6.3 Leaching of sensor layers M4, M1, M2 and M3 (from top) on exposure to a flow of buffer solution (left) and titration plots of AF in poly-TMOS (Ml), an organically modified silicate (M4), and covalently immobilized on ICPS (M2) and GOPS (M3) (right). (Reproduced from ref. 4, with permission.)...

Scanning electron microscopy (SEM) used to investigate the structure of similar organically modified silicate (ORMOSIL) films shows that certain [Ru(dpp)3]2+-doped octyl-triethylorthosilicate (triEOS)-tetra-ethylorthosilicate (TEOS) composites form uniform, crack-free xerogel films (Figure 6.6) that can be used to construct high-sensitivity oxygen... 

Figure 6.5 A fluorinated organically modified silicate doped with [Ru(dpp)3]2+ is a highly sensitive 02 sensor. Fluorine here ensures unprecedented sensitivity and a remarkable stability (2% drift over 6 months). The material has been implemented in sol-gel handheld oxygen sensors that are already commercialized. (Reproduced from ref. 6, with permission.)...

D. A. Higgins, M. M. Collinson, G. Saroja and A. M. Bardo, Single-Molecule Spectroscopic Studies of Nanoscale Heterogeneity in Organically Modified Silicate Thin Films, Chem. Mater., 2002, 14, 3734. 

A. Walcarius and C. Delacote, Rate of Access to the Binding Sites in Organically Modified Silicates. 3. Effect of Structure and Density of Functional Groups in Mesoporous Solids Obtained by the Co-Condensation Route, Chem. Mater., 2003, 15, 4181. 

M. M. Collinson and B. Novak, Diffusion and Reactivity of Ruthenium (II) Tris(bipyridine) and Cobalt (II) Tris(bipyridine) in Organically Modified Silicates, J. Sol-Gel Sci. Technol., 2002, 23, 215. 

Koo YE, Cao Y, Kopelman R, Koo SM, Brasuel M, Philbert MA (2004) Real-time measurements of dissolved oxygen inside live cells by organically modified silicate fluorescent nanosensors. Anal Chem 76 2498-2505... 

Y.-E. L. Koo, Y. Cao, R. Kopelman, S. M. Koo, M. Brasuel, and M. A. Philbert, Real-Time Measurements of Dissolved Oxygen Inside Living Cells by Organically Modified Silicate Fluorescent Nanosensors, And, Chem. 2004, 76, 2498. 

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