Coordination-restricted dehydrogenative coupling of 1,4-BPyB on
Au(111) with coordinated Fe atoms. (a) Coordinated honeycomb network
formed by three-fold coordination of 1,4-BPyB and Fe atoms. (b) Detailed
STM image of the coordinated network. (c) Molecular model of a coordinated
trimer. (d) Compound network emerging after triggering the dehydrogenative
coupling at 350 K. Such network is composed of well-organized pristine
1,4-BPyB and product D through three-fold coordination interaction.
(e) Close-up image showing details of the compound network of octagonal
cavities in panel d. The contour of a product D has been marked in
white. (f) Schematic diagram interpreting the molecular structure
of product D and the formation of compound network with D as the only
product. (g, h) Calculated reaction path and energies of different
intermediate states based on a pyridine ring on Au(111) with one coordinated
Fe atom and one free Au adatom. The white arrows in panels a and d
point to [11̅0] direction. Scanning parameters: (a, d) constant-current
mode, Vb = 0.5 V, It = 30 pA; (b) constant-height
mode, Vb = 50 mV, It = 60 pA; (e) constant-height
mode, Vb = 10 mV, It = 70 pA.