[12a-N302-1~10] 12.2 Characterization and Materials Physics

△ [12a-N302-4] Single-molecule Observation of Complexation Reaction and Control of Reactivity

〇(DC)Takanori Harashima¹, Nishino Tomoaki¹ (1.TokyoTech)

Keywords:single-molecule, scanning probe microscope, charge transfer complex

This study investigated the charge transfer complexation on a single-molecule scale using electrical conductance measurements. 1,4-bis(4-aminophenoxy)benzene (APB) was used as electron donor and methyl viologen (MV) as electron acceptor. As a result, the complexation and dissociation on the single-molecule wire of APB were successfully identified by conductance, and the binding constant was determined to be 20 M^-1. On the other hand, the binding constant of 0.56 M^-1 was obtained from UV-vis spectrum. The binding constant increased significantly at the single-molecule wire. This result is due to the increase in the local concentration of MV, a divalent cation, near the nanogap by the formation of the electric double layer.