| Abstract
| - The rate of electron transfer is measured to two ferrocene and one iron tetraphenylporphyrin redox speciescoupled through terminal acetylenes to azide-terminated thiol monolayers by the Cu(I)-catalyzed azide−alkyne cycloaddition (a Sharpless “click” reaction) to form the 1,2,3-triazole linkage. The high yield,chemoselectivity, convenience, and broad applicability of this triazole formation reaction make such a modularassembly strategy very attractive. Electron-transfer rate constants from greater than 60,000 to 1 s-1 are obtainedby varying the length and conjugation of the electron-transfer bridge and by varying the surrounding diluentthiols in the monolayer. Triazole and the triazole carbonyl linkages provide similar electronic coupling forelectron transfer as esters. The ability to vary the rate of electron transfer to many different redox speciesover many orders of magnitude by using modular coupling chemistry provides a convenient way to studyand control the delivery of electrons to multielectron redox catalysts and similar interfacial systems thatrequire controlled delivery of electrons.
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