Thiol hybridization

Resins with varying properties from toughened plastics to high elongation elastomers can be formed. Many acrylate thiol hybrid polymerizations that result in modifications of mechanical properties of the polymeric network are... 

Sulfur is most commonly encountered in biological molecules either in compounds called thiols, which have a sulfur atom bonded to one hydrogen and one carbon, or in sulfides, which have a sulfur atom bonded to two carbons. Produced by some bacteria, methanethiol (CH3SH) is the simplest example of a thiol, and dimethyl sulfide [(ChP S l is the simplest example of a sulfide. Both can be described by approximate sp3 hybridization around sulfur, although both have significant deviation from the 109.5° tetrahedral angle. 

Disulfide(s), 668 from thiols, 668 hybridization of, 20 reduction of, 668 thiols from. 668... 

Thiol (s), 652, 667-668 disulfides from, 668 electrostatic potential map of, 75 from alkyl halides, 667 hybridization of, 20 naming, 667 odor of, 667 oxidation of, 668 pKa of, 604... 

Ghosh, S.S., Kao, P.M., McCue, A.W., and Chappelle, H.L. (1990) Use of maleimide-thiol coupling chemistry for efficient syntheses of oligonucleotide-enzyme conjugate hybridization probes. Bioconjugate Chem. 1, 71-76. 

As well as fluorescence-based assays, artificial membranes on the surface of biosensors offered new tools for the study of lipopeptides. In a commercial BIA-core system [231] a hydrophobic SPR sensor with an alkane thiol surface was incubated with vesicles of defined size distribution generating a hybrid membrane by fusion of the lipid vesicles with the alkane thiol layer [232]. If the vesicles contain biotinylated lipopeptides their membrane anchoring can be analyzed by incubation with streptavidine. Accordingly, experiments with lipopeptides representing the C-terminal sequence of N-Ras show clear differences between single and double hydrophobic modified peptides in their ability to persist in the lipid layer [233]. 

Figure 5.22 Cu UPD on a Au/mica substrate modified by a hybrid nanostructure consisting of a hydrogen-bonded network and a thiol SAM. (a) Cartoon ofthe hybrid structure and molecular structures of the components. The hydrogen-bonded network is composed of 1,3,5-triazine-2,4,6-triamine (melamine, triangles) and perylene-3,4,9,10-tetracarboxylic di-imide (PTCDI, rectangles) that interact via a triple hydrogen bond (dotted lines). Pores ofthe...

The possibility of orbital reorganization in ion-radicals should be taken into account. Thus, organic derivatives of three-valence phosphorus exist in the sp hybrid state and an electron is removed from one of these orbitals. The cation-radical formed can retain the initial orbital configuration, but can also convert into the sp d hybrid state. In the latter case, one additional orbital of the phosphorus atom becomes accessible for the reactant attack. If Y—H bond in the reactant is weak, the reaction R3P+ -f YH proceeds with the participation of an sp frontal orbital according to the radical mechanism. Thiols are typical reactants with the weak Y—H bonds. If anions (A ) react with RjP, the vacant sp d orbital of the phosphorus appears to be a target. Scheme 3.14 illustrates the orbital pictures and the reaction directions. 

SAMs of thiols (and thiol-modified ONDs) can be highly ordered and densely packed, improving the availability of active surface groups (and capture probes) for binding and hybridization. However, dense packing may not always be advantageous in DNA hybrid capture. Steric hindrance effects can occur if the immobilized capture probes are too close together. 

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