Thiol functional groups, surface

Amphiphilic compounds also are used to constmct self-assembled monolayers on gold surfaces. The usual agents have a thiol functional group at one end to bind to the gold and a methyl group or some organic functional group at the other end. 

Ligands A, B, and C have similar chemical structures. They all carry an end thiol functional group (for attaching onto a gold surface of a QCM device), an alkane chain (to form the well-packed SAM ), and a triethylene glycol linker (to prevent nonspecific adsorption ). The resulting 1 1 mixed SAMs... 

Figure 2.2 A number of small thiol-containing molecules have proven useful for modification of gold or metallic surfaces. The dithiol derivatives provide better dative bond stability and can t be displaced easily by competing thiols or oxidation. Most thiol-containing compounds used for surface modification also contain terminal functional groups or reactive groups for coupling affinity ligands.

Advances have been achieved in recent years, such as the use of CL reagents as labels to derivatize and sensitively determine analytes containing amine, carboxyl, hydroxy, thiol, and other functional groups and their application in HPLC and CE [35, 36], the synthesis and application of new acridinium esters [37], the development of enhanced CL detection of horseradish peroxidase (HRP) labels [38], the use of immobilization techniques for developing CL-based sensors [39-42], some developments of luminol-based CL in relation to its application to time-resolved or solid-surface analysis [43], and the analytical application of electrogenerated CL (ECL) [44-47], among others. 

M. Buck reviews in great depth the literature on self-assembled monolayers (SAMs) of thiols on gold, a classic means of surface modification. The wide variety of functional groups that is provided by synthetic chemists makes thiol-SAMs an exciting playground for applications where the gap between two worlds, the inorganic and the organic, needs to be closed. Examples are molecular electronics and biochemistry. 

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