Table 2. Comparison of covalent bond rupture energies, distances, and forces for all covalent single bonds present in the experiment as well as for the Au-S bond. - PDF Document

Presentation Transcript

  1. Table 2.Comparison of covalent bond rupture energies, distances, and forces for all covalent single bonds present in the experiment as well as for the Au-S bond. Theoretical Experimental Theoretical (this work) Au-S† Au-Au 44 Bond C-O C-N C-S C-C C-S (TTF) 55 C-S (TTF2+) 55 C-C (TTF2+) 55 Deslipping 46 8.61 Bond energy, kcal•mol-1 Rupture distance, Å Rupture force, nN 85-91 69-75 61 83-85 1.43 1.38 1.82 1.54 2.4 1.77 1.68 1.47 2-13 >1.0‡ >1.0‡ >1.0‡ 0.074§ 4.3 4.1 3.7‡ 1.4 †Room temperature experiments measuring the rupture of alkane-thiols on Au surfaces and of gold nanowires have both given rupture forces of 1.4-1.5 ± 0.3 nN. It is unclear whether the Au-S bond is rupturing in experiment involving alkane-thiols on Au surfaces or whether Au-Au rupture is being observed. ‡The experimental loading rate for rupture of the C-S bond was not reported. Rupture values for the C-S bonds in TTF as well as C-S and C-C bonds in TTF2+ are expected to require >1 nN given the similarities in bond energies and distances to experimental data for the C-S bond and the fact that all published accounts of covalent bond rupture indicate rupture forces much greater than 1 nN. §The value of 0.074 nN is taken from the experimental AFM measurements presented in this work, which has been attributed to deslipping based on experimental and theoretical studies.