Structure of thiols

Influence of the Structure of Thiol and Enone on the Course of the Asymmetric Thiol... 

Fig. 4.4.7 Models for the surface structures of thiol-modified Agl particles. The shadow represents the inner part of particles. The solid and dashed lines show the surface and adsorbed ions, respectively. Structure A stands for the half-filled model and B for highest coverage model. (From Ref. 10.)...

Figure 4.33 General structure of thiol-derivatized siloxane polymers...

Potential dependent halide adsorption, including order-disorder phenomena, is well known [134, 246, 247], and it is reasonable to expect that the breakdown of the PEG-C1 blocking layer might also be potential dependent. In a similar fashion, the composition and structure of thiols and disulfides adsorbed on gold from simple electrolytes have been shown to be potential dependent [282]. In the present example, it is also possible that the approach of SPS to the electrode surfaces is screened by complexation with the potential dependent concentration of Cu+ that is generated at the electrode. Importantly, the equilibrium Cu+ concentration in the additive-free system (i.e. Equations 2.1 and 2.2) is of the order of 400 (tmol L 1 and Cu+ is known to form complexes with all the additives under consideration [239, 279, 280, 283-285]. Furthermore, the equilibrium Cu+ concentration decreases exponentially with potential, that is, 60 mV per decade of concentration [283-285]. Thus, the increasing rate of SPS adsorption with... 

Figure 4.2 Schematic structure of thiol-organosilica nanoparticles.

The free-radical chemistry of fluoroalkanesulfenyl chlorides with hydrocarbons was also investigated [S, 9], Depending upon the structures of the sulfenyl chloride and the hydrocarbon, these reactions yield as major products up to three of the following four types of organic compounds thiols, disulfides, sulfides, and chlorohydrocarbons (equation 6), Perfluoroisobutanesulfenyl chloride is unique m that the only major products detected are the thiol and chlorohydrocarbon [ ] (equation 6) (Table 3). 

Another example of the shape similarity effect on molecular recognition involves the similarity between the structures of the binding sites. Investigation was made for four reaction systems I-IV each consisting of a 1 1 mixture of thiols HS—X and HS—Y... 

The 20 common amino acids can be further classified as neutral, acidic, or basic, depending on the structure of their side chains. Fifteen of the twenty have neutral side chains, two (aspartic acid and glutamic acid) have an extra carboxylic acid function in their side chains, and three (lysine, arginine, and histidine) have basic amino groups in their side chains. Note that both cysteine (a thiol) and tyrosine (a phenol), although usually classified as neutral amino acids, nevertheless have weakly acidic side chains that can be deprotonated in strongly basic solution. 

Osmium tetroxide, reaction with alkenes, 235-236 toxicity of, 235 Oxalic add, structure of, 753 Oxaloacetic acid, structure of, 753 Oxetane, reaction with Grignard reagents, 680 Oxidation, 233, 348 alcohols, 623-626 aldehydes, 700-701 aldoses, 992-994 alkenes, 233-236 biological, 625-626 phenols, 631 sulfides, 670 thiols, 668... 

The pharmaceutical interest in the tricyclic structure of dibenz[6,/]oxepins with various side chains in position 10(11) stimulated a search for a convenient method for the introduction of functional groups into this position. It has been shown that nucleophilic attack at the carbonyl group in the 10-position of the dibenzoxepin structure renders the system susceptible to water elimination. Formally, the hydroxy group in the enol form is replaced by nucleophiles such as amines or thiols. The Lewis acids boron trifluoride-diethyl ether complex and titanium(IV) chloride have been used as catalysts. 

Propiolactone is one example. It will alkylate amino, imino, hydroxyl and carboxyl groups, all of which occur in proteins, and react also with thiol and disulphide groups responsible for the secondary structure of proteins and the activity of some enzymes. 

Sulfiir-anchored SAMs and thin films, mostly from organosulfiir precursors, have been discussed at length by a number of authors [10, 181]. SAMs of organosulfiir compounds (thiols, disulfides, sulfides) form on gold substrates by spontaneous adsorption from either the liquid or the vapor phase. A number of experimental factors can affect the formation and structure of SAMs such as choice of solvent, temperature, concentration, immersion time, purity of adsorbate, oxygen concentration in solution, cleanliness, and structure of the adsorbate. Interestingly, the... 

Figure 25. Formation of an artificial structure of metal nanoparticles by dip pen nanolithography using an AFM (a), tip to transport functionalized thiol molecules onto a gold surface (b) and to trap the nanoparticles (c).

Dijkwel, P.A. and Wenink, P.W. (1986). Structural integrity of the nuclear matrix differential effects of thiol agents and metal chelators. J. Cell Sci. 84, 53-67. 

A recently developed application of the Ramberg-Backlund reaction is the synthesis of C-glycosides. The required thioethers can be prepared easily by exchange with a thiol. The application of the Ramberg-Backlund conditions then leads to an exocyclic vinyl ether that can be reduced to the C-nucleoside.95 Entries 3 and 4 in Scheme 10.6 are examples. The vinyl ether group can also be transformed in other ways. In the synthesis of partial structures of the antibiotic altromycin, the vinyl ether product was subjected to diastereoselective hydroboration. 

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