Fig. 2: On-surface synthesis of 3D-OMC and electronic properties of the unit before and after debromination.

a Schematic drawings of the three-dimensional organometallic compound (3D-OMC) and its diradical species. Red, blue and yellow balls in c, d correspond to Br, H, and Ag atoms. Grey lines correspond to C-C bonds, respectively. b Large-scale STM image of 3D-OMCs synthesized on Ag(111). c Close view before and d after tip-induced debromination. e dI/dV curves measured on the dibrominated naphthyl group 1 and f after the tip-induced debromination. The dI/dV curves were measured at the sites indicated by cross markers with the same colors in e and f. g, h dI/dV maps taken at LUMO and HOMO energy levels on 1 and the debrominated unit. i, j Simulated constant height STM images at the labelled bias voltages and k, l the associated PDOS calculated from m, n the DFT optimized structures on five-layer Ag(111) surfaces on the left, and calculated HOMO and LUMO in vacuum (ROB3LYP-D3/6-311 G**) at the middle and right, respectively. Purple, green, white balls correspond to Br, C, and H, respectively. Purple and light red surfaces represent the relative signs of the orbital coefficients drawn at 0.04 e bohr⁻³ level. Measurement parameters: Sample bias voltage V = 500 mV and tunneling current I = 2 pA in b, V = 200 mV and I = 5 pA in c, and V = 1 V and I = 10 pA in d.