Derivative hybrid

Shchipunov, Yu.A., Karpenko, T.Yu., Bakunina, I.Yu., Burtseva, Yu.V. and Zvyagintseva, T.N. (2004) A new precursor for the immobilization of enzymes inside sol-gel derived hybrid silica nanocomposites containing polysaccharides. Journal of Biochemical and Biophysical Methods, 58, 25-38. 

B. Arkles, Commercial applications of sol gel-derived hybrid materials, MRS Bull., 2001, May, 402. 

Whilst in some cases near-stoichiometric amounts of reagents can be used [16], the excess (5-10 equiv.) of ketone reagent is preconceived in order to ensure convenient kinetics and conversion. Reactions can be run typically at room temperature [20] in a polar aprotic solvent such as CHC13, or in THF or i-PrOH. The presence of water was noted to be beneficial in some cases [21]. In ionic liquids, such as in [bmim]BF4, a low (5 mol%) catalyst concentration can be applied, while the enantioselectivity of the alkylation is modest in this solvent [22]. The ionic liquid-derived hybrid catalyst 10, used neat with a small amount of trifluoroacetic acid (TFA) as co-catalyst, affords quantitatively 4, though in a remarkably high dr syn/anti = 99/1) and ee (99%). It should be noted that this catalyst can easily be recovered by extraction, and re-used without loss of activity. 

Sol-gel derived hybrid materials are used as heterogeneous catalysts for the synthesis of N,N-dimethylformamide (dmf) using scC02 as both solvent and reactant. Results are compared to conventional homogeneous and heterogeneous catalysts. The turnover numbers exceed those reported so far for dmf synthesis by heterogeneous catalytic routes by more than three orders of magnitude. 

Amal-Herault C, Barboiu M, Pasc A, Michau M, Perriat P, van der Lee A (2007) Constitutional self-organization of adenine-uracil-derived hybrid materials. Chem Eur J 13 6792-6800... 

B. Alkies, Commercial Applications of Sol-Gel-Derived Hybrid Materials, MRS Bulletin, 402-407, 2001. 

Sol-gel derived hybrid Ti02 film deposited on glassy carbon electrode has been used to construct the phenol biosensor. The resulting biosensor is selective towards phenol with a linear range from 7.5 x 10 8 - 6 x 10"6 M with detection limit 1 x 10"8 and has response time as 10 s. The biosensor exhibits maximum response at 45 °C. The initial response current of the bioelectrode decreases to 95 % after 2 months [85],... 

Horiuchi, Y, Abe, K., Hirayama, F., Uekama, K. Control of dieophyl-hne by p-cyclodextrin derivatives hybridizing of hydrophihc and ionizable p-cyclodextrin complexes. J. Control Release 1991, 15, 177-182. 

Patient cells are fused witli a specially designed rodent cell line, creating hybrids that stably retain a subset of tlie human chromosomes. About one-quar ter of the derived hybrids contain a single copy of any human chromosome of interest. The diploid nature of the human genome is tliereby converted to a haploid state in which mutations are easier to detect because they are not accompanied by the normal sequence of the wild-type allele. Conversion is not a substitute for the detection methods described above, but rather a technique that provides improved templates and increased sensitivity. 

Model reactions of epoxypropane and epoxyhexane were analysed using Fourier Transform-Raman spectroscopy and Carbon-13 NMR spectroscopy to obtain information on the possible products of ring opening in epoxy silane-based sol-gel derived hybrid polymers. A mixture of epoxyalkane, tetramethoxysilane and aluminium sec-butylate was employed to investigate behaviour during the sol-gel process. Raman band and NMR peak assignments for various reaction products are presented and discussed. 24 refs. 

Rodrigues, D. E. Wilkes, G. L., Structure-Property Behavior of Sol-Gel Derived Hybrid Materials Using Microwave Processing. Prepr., Am. Chem. Soc., Div. Polym. Chem. 1989, 30(2), 227. 

Mansur Herman S., Orefice Rodrigo L., and Mansnr Alexandra A. P. Characterization of poly(vinyl alcohol)/poly(ethylene glycol) hydrogels and PVA-derived hybrids by small-angle X-ray scattering and FTIR spectroscopy. Polymer. 45 no. 21 (2004) 7193-7202. 

Some examples of the rich information provided by IR spectroscopy, described in this chapter, include the material structural evolution during the different stages of sol-gel processing, the detection of OH species and porosity, the analysis of structural homogeneity, phase separation and densification degree and the study of structural differences between thin films, thicker multilayer films and bulk sol-gel samples, as well as between purely inorganic and sol-gel derived hybrid materials. 

TABLE 7-5. ASSIGNMENTS OF THE VIBRATIONAL MODES IN MPTMS DERIVED HYBRIDS (ADAPTED FROM MEDDA, 2003)... 

Mackenzie J.D., Bescher E. Some factors governing the coating of organic polymers by sol-gel derived hybrid materials. J. Sol-Gel Sd. Technol. 2003 27 7-14 Makishima A., Mackenzie J.M. Hardness equation for Ormosils. J. Sol-Gel Sci. Technol. 2000 19 627-630... 

Brennan A, Wilkes G.L. Stmctnre-property behaviour of sol-gel derived hybrid materials Effect of a polymeric acid catalyst. Polymer 1991 32(N.4) 733-739 Ceram. Trans. 1995 55 291-298 Choi J., Harcup J., Yee A.F., Zhu Q, Laine R. Organic/inorganic hybrid composites from cubic silsesquioxanes. J. Am. Chem. Soc. 2001 123 11420-11430 Coltrain B.K., Sanchez C., Schaefer D.W., Wilkes G.L. (Eds.), Better Ceramics Through Chemistry VII Organic/inorganic Hybrid Materials. Pittsburgh Materials Research Society, 1996... 

LebeauB., HerletN., Livage J., Sanchez C. Optical properties of a near-infrared dyes lasa-incorporated inside sol-gel matrices. Chem. Phys. Lett. 1993 206(1-4) 15-20 Lebeau B., Sanches C. Sol-gel derived hybrid inorganic-organic nanocomposites for optics. Curr. Opin. Solid State Mater. Sci. 1999 4 11-23... 

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