Fig. 2

Molecular conformers and assembled structures of intact p-DBTB. a STM overview of the Kagome networks monitored at T = 113 K. A unit cell is highlighted by the rhombus (a = b = 3.35 nm, γ = 60°). b Most of the molecules appear in the trans-D_2h shape. A “defect”, C_2v-conformer, is indicated by an ellipse. Tentative structural model of a trimeric cluster is overlaid. Carbon, gray; nitrogen, blue; bromine, red; hydrogen, white. c Br···Br halogen bonds of a trimeric cluster. d–f Magnified topographs of the trans-D_2h, C_2v and cis-D_2h conformers, overlaid by the corresponding molecular models. g A close-packed island composed of cis-D_2h conformers observed at 293 K. A “defect”, C_2v conformer, is marked by an ellipse. h Tentative structural model of the close-packed structure. i Spontaneous conformational transition of the molecules monitored at 293 K. One C_2v conformers (marked by an arrow) was transformed into a cis-D_2h conformer during a continuous scanning in 3 min. Scale bars: (a) 5 nm; (b) 2 nm; (g) 3 nm. Data acquisition conditions (U, I, T): (a, b, d and e) −1.5 V, 0.2 nA, 113 K; (f) −1.2 V, 0.1 nA, 293 K; (g, i) −1.2 V, 0.1 nA, 293 K