Single Tripyridyl–Triazine Molecular Junction with Multiple Binding Sites

Abstract

We present an electronic characterization of a single molecular junction of 2,4,6-tris(2′,2″,2‴-pyridyl)-1,3,5-triazine (TPTZ) with multiple metal–molecule binding sites using scanning tunneling microscopy-based break junction method under ambient conditions. The TPTZ molecule consists of a centered triazine moiety and surrounding three 2-pyridyl groups. The benzene rings containing a N atom in TPTZ act as molecular binding sites for bridging a gap between two Au electrodes to form a single molecular junction. Because the N atom at the ortho-position in the 2-pyridyl groups is spatially hidden from the electrode surfaces, the single molecular junction forms via direct metal−π couplings. We demonstrated that the single TPTZ molecular junctions exhibit highly conductive character up to 10–1 G0 (G0 = 2e2/h), which is due to the effect of the direct metal−π coupling. We found three preferential conductance states of ca. 10–1, 10–2, and 10–4 G0, which suggests that the single TPTZ molecular junctions have thre...