STM images of 1a. The diameter of the bright spots is about 1.0±0.1 nm, which is consistent with the size of the TP core. A unit cell for 1a structure is outlined with parameters of a = 3.0 ± 0.1 nm, θ = 85° ± 3°. (a) Large-scale STM image (60 nm × 60 nm) of a self-assembled monolayer of 1a on an HOPG surface. The imaging conditions were I_tip = 299 pA, V_bias = 650 mV. (b) High-resolution STM image (25 nm × 25 nm) of 1a self-assembly. The imaging conditions were I_tip = 358 pA, V_bias = 750 mV. (c) Structure model for 1a self-assembly.