Thermodynamics and Selectivity of Two-Dimensional Metallo-supramolecular Self-Assembly Resolved at Molecular Scale

Abstract

We investigated the thermodynamic processes of two-dimensional (2D) metallo-supramolecular self-assembly at molecular resolution using scanning tunneling microscopy and variable-temperature low-energy electron diffraction. On a Au(111) substrate, tripyridyl ligands coordinated with Cu in a twofold Cu-pyridyl binding mode or with Fe in a threefold Fe-pyridyl binding mode, forming a 2D open network structure in each case. The network structures exhibited remarkable thermal stability (600 K for the Cu-coordinated network and 680 K for the Fe-coordinated network). The Fe-pyridyl binding was selected thermodynamically as well as kinetically in self-assembly involving both modes. The selectivity can be effectively suppressed in a specifically designed self-assembly route.

Tuning two-dimensional band structure of Cu(111) surface-state electrons that interplay with artificial supramolecular architectures

“…1(a) and 1(b), the self-assembly of M1 or M2 resulted in large domains of network architectures with a honeycomb motif stabilized via pyridyl-Cu-pyridyl coordination bonds, 26,27 and denoted S1 or S2, respectively. M3 molecules underwent debromination and formed a honeycomb organometallic structure [cf.…”

Cooperative Modulation of Electronic Structures of Aromatic Molecules Coupled to Multiple Metal Contacts

“…As shown in Fig. 1(a), molecules of 1,3,5-tris(pyridyl)benzene (TPyB) self-assemble into a honeycomb network structure, wherein the adjacent TPyB molecules are linked via pyridyl-Cu-pyridyl coordination bonds involving the molecules' N atoms [22,23]. In the interior of the network domains each molecule is laterally coupled through three coordination bonds while at the edge of the network domains each molecule is coupled through two coordination bonds.…”

Site-specific bonding of copper adatoms to pyridine end groups mediating the formation of two-dimensional coordination networks on metal surfaces

“…The bonding structure is very unlikely for uncoordinated pyridine groups due to the repulsive character of the nitrogen lone-pair electrons and, therefore, suggests the presence of a bridging Cu adatom. Twofold coordination of Cu atoms with nitrogen-based end groups is known from previous works on metal-organic networks on metal surfaces [6,[13][14][15].…”

“…Self-assembled metal-organic networks consisting of molecular linkers and metal species provide longrange order [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] and a programmable network architecture based on the interplay of the functionalized parts of the organic molecule and the metal species. With the choice of the symmetry and size of the organic linker, the geometry of the metal-organic network can be tuned [5,6].…”

“…1(a). The nitrogen sites of the pyridine rings are known to form metal-organic bonds with transition-metal atoms via their lone-pair electrons [12][13][14][15][16]. In T4PT also the lone-pair electrons of the triazine nitrogen atoms may participate in forming bonds.…”