Non-covalent derivatization

Harnessing bioinspired phenomena such as molecular recognition and self-assembly, a new approach termed Non-Covalent Derivatization was developed. The properties of hydroquinone were successfully altered by incorporating the hydroquinone molecules in a matrix with compatible alkylterephthalamide molecules. This was achieved via one-step solventless... 

Pollution Prevention via Molecular Recognition and Self Assembly Non-Covalent Derivatization. Warner, J. C., in Green Chemistry Frontiers in Benign Chemical Synthesis and Processes Anastas, P. and Williamson, T. Eds., Oxford University Press, London, pp 336 - 346. 1998. 

Two different techniques have been developed for MIP production, namely the covalent and the non-covalent approaches. The covalent way is based on the chemical derivatization of the template with molecules containing polymerizable groups using reversible covalent bonds. Different chemical reactions can be ap-... 

The modification of the exposed reactive groups, depending upon the nature of the modifying group may disrupt the non-covalent interactions, cause alteration in conformation of the protein with concomitant changes in physical properties. Chemical derivatization may be used to alter the reactivities of food proteins, to alter their thermal stability or to render them more water soluble. 

Chromatographic enantioseparations can be achieved when the diastereoisomeric interaction is established via a precolumn covalent derivatization, or a non-covalent association formed within the chromatographic system through the use of chiral mobile phase additives (primarily an LC technique) or chiral stationary phases. 

An enantioseparation in this mode is based on the formation of non-covalent diastereomer-ic complexes between the enantiomers of an analyte and the chiral additive in the mobile phase (CAMP). Compared with indirect enantioseparations, the CAMP technique has advantages such as the absence of a derivatization step or a higher flexibility (easier change of a chiral additive than a chiral or an achiral packing material). As documented by Davan-kov [105], the enantiomer migration order with CAMP most likely will be opposite to that observed with the same chiral selector as the stationary phase. The complementary enantio-selectivity of enantioseparation with CAMP compared with CSPs is a significant advantage. 

Sun and co-workers exploited the selectivity in the non-covalent functionalization of SWNTs with planar aromatic molecules, such as derivatized porphyrin or pyrene (Figure 6.3), for the post-production separation. The separation method simply splits the starting nanotube mixture by selectively solubilizing semiconducting SWNTs and leaving their metallic counterparts behind, and consequently is capable of handling significant sample quantities. Experimentally, as-produced samples of... 

Covalent derivatization of proteins in this instance dictated the modes of separation and enhanced detection sensitivity. Non-covalent dye-protein interactions can alternatively be exploited to facilitate protein determination by ju-chip electrophoresis with LIF detection, thus offering greater... 

Czerwenka, C, Maier, N.M., Lindner, W. (2004) Enantiomer discrimination by mass spectrometry non-covalent interactions of an N-derivatized dipeptide with various cinchona alkaloid derivatives and comparison with enantioselective liquid-phase separations. Anal. Bioanal. Chem., 379,1039-1044. 

There are several methods available for preparing surface functionalized metallic colloids for use as biological labels. The three most widely used fabrication methods include non-covalent absorption of biomolecules to the particle su face binding to the metal surface via a thiol functionalized cross linker, and covalent binding to a derivatized silica or polystyrene shell that encompasses the metal particle . 

The indirect approach has been widely applied since many functional groups can be derivatized with various chiral reagents and the covalent diastereoisomers can be separated with inexpensive non-chiral systems. Other advantages of the indirect approach are that method development is rather straightforward and that the detection sensitivity of the enantiomers can be improved by the selection of an appropriate CDR having a strong chromophor or fluorophor. 

Polystyrene does not enable the covalent, reversible attachment of synthetic intermediates unless the support is derivatized with suitable functional groups. The most common groups for the reversible attachment of intermediates are chloromethyl and hydroxymethyl, whereas aminomethyl groups are mainly used as non-cleavable points of attachment for linkers (see Chapter 3). 

Polyfunctional mercaptans. Polyfunctional mercaptans are some of the most powerful odorants in nature, and they must be quantified at extremely low levels. The methods developed for their determination make use either of a selective separation using -hydroxy-mercurybenzoate (Tominaga et al. 1998 Tominaga and Dubourdieu 2006 Ferreira et al. 2007), of covalent chromatography (Schneider et al. 2003) or of the derivatization with pentaflurobenzyl bromide (Mateo-Vivaracho et al. 2006, 2007). A recent report using non-selective headspace isolation with SPME has also been published, but the limits of quantification are more than one order of magnitude above the odor thresholds (Fedrizzi et al. 2007). 

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