Alkyl-Modified Gold Surfaces: Characterization of the Au–C Bond

The surface of gold can be modified with alkyl groups through a radical crossover reaction involving alkyliodides or bromides in the presence of a sterically hindered diazonium salt. In this paper, we characterize the Au–C(alkyl) bond by surface-enhanced Raman spectroscopy (SERS); the corresponding peak appears at 387 cm–1 close to the value obtained by theoretical modeling. The Au–C(alkyl) bond energy is also calculated, it reaches −36.9 kcal mol–1 similar to that of an Au–S–alkyl bond but also of an Au–C(aryl) bond. In agreement with the similar energies of Au–C(alkyl) and Au–S–(alkyl), we demonstrate experimentally that these groups can be exchanged on the surface of gold.