Rate of Interfacial Electron Transfer through the 1,2,3-Triazole Linkage

Abstract

The rate of electron transfer is measured to two ferrocene and one iron tetraphenylporphyrin redox species coupled 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 modular assembly strategy very attractive. Electron-transfer rate constants from greater than 60,000 to 1 s −1 are obtained by varying the length and conjugation of the electron-transfer bridge and by varying the surrounding diluent thiols in the monolayer. Triazole and the triazole carbonyl linkages provide similar electronic coupling for electron transfer as esters. The ability to vary the rate of electron transfer to many different redox species over many orders of magnitude by using modular coupling chemistry provides a convenient way to study and control the delivery of electrons to multielectron redox catalysts and similar interfacial systems that require controlled delivery of electrons.

Inhibiting platelet-stimulated blood coagulation by inhibition of mitochondrial respiration

“…Compounds 1a, 3b, and 3c, the CcO model, (4-((4-azidophenyl) ethynyl)phenyl)methanethiol, and Tris-(benzyltriazolylmethyl)amine (TBTA) were synthesized according to literature procedures (23)(24)(25)(26)(27)(28). The compound 1d was obtained from the Developmental Therapeutics Program Open Chemical Repository at the National Cancer Institute.…”

Synthesis of giant globular multivalent glycofullerenes as potent inhibitors in a model of Ebola virus infection

“…27 The absence of a well resolved peak around 405.0 eV demonstrates the lack of the electron-deficient nitrogen of the azide group in the final compound. 28,29 The composition of compounds 17b and 17c has also been ascertained by their respective XPS analyses which showed the presence of the expected elements, according to their relative abundance (see Supplementary Figure 4 Previous inhibition studies using the same infection model and fullerenes displaying up to 36 mannoses show relative inhibitor potency (RIP) values at least two orders of magnitude smaller. 19 Moreover, huge virus-like particles (VLP) with a radius of 16 nm and up to 1640 mannoses 33 were 18 fold less potent than compound 17c described in this work (see Supplementary Table 2).…”

Role of a distal pocket in the catalytic O 2 reduction by cytochrome c oxidase models immobilized on interdigitated array electrodes

“…2) as a function of (i) the oxygen association rate [k on (O 2 )] and the rate of hydrolysis, both associated with the presence of water in the gas binding pocket, and (ii) the availability of electrons at the oxygen reduction site associated with the rate of electron arrival from the electrode to the catalyst [k(eT)] and/or the presence of redox active species in the vicinity of the heme. The latter aspects were specifically addressed in previous studies by immobilizing the active-site models onto self-assembled-monolayer (SAM)-coated rotating ring disk gold electrodes (RRDE) (8)(9)(10): k(eT) was controlled by the length and conjugated character of the linker between the catalyst and the gold electrode, and immobilization allowed site isolation. To get better collection efficiencies for the detection of PROS and to prevent damage to the SAM associated with high rotation rates, the present study used Au-Pt interdigitated array electrodes (IDAs).…”