Coverage dependent structures of oligopyridine adlayers on (111) oriented Ag films

Abstract

The coverage dependent formation of ordered structures in vapor deposited 2,4'-bis(terpyridine)derivatives (2,4'-BTP) on (111) oriented Ag films was investigated by STM. Following a two-dimensional (2D) disordered gas phase at lowest coverages, a sequence of at least three ordered structures is observed with increasing coverage. These include a 'parallel chain structure' (PCS), a 'quasi-quadratic network' (QQN) structure, and a 'packed windmill structure' (PWS), with ideal coverages of 0.37, 0.4, and 0.44 molecules nm(-2). At intermediate coverages between 0.37 and 0.44 molecules nm(-2), these structures coexist in larger islands. The energetics of the different phases, whose structures are mainly determined by attractive C-H[dot dot dot]N bridges, are discussed in a picture including C-H[dot dot dot]N and C-H[dot dot dot]H-C interactions and lateral variations in the substrate-adsorbate interactions.

Intermolecular vs molecule–substrate interactions: A combined STM and theoretical study of supramolecular phases on graphene/Ru(0001)

“…These linear networks are characterized by their anti-parallel arrangement of the molecules. Similar to the adsorption of 2,4’-BTP molecules [4,12] on Ag thin films, these linear networks also exhibit intermolecular bonds between the linear elements. Finally, it is interesting to note that comparable 2D phases based on bent structures with 60° angles between different linear parts were not observed on HOPG.…”

“…It is well known that the formation of highly ordered 2D supramolecular networks on smooth surfaces, such as metal substrates or highly oriented pyrolytic graphite (HOPG), is mainly governed by the intermolecular interactions between adjacent molecules due to hydrogen bonding [1–4], covalent bonding [5–6], or, in the case of metal organic networks, by metal–ligand interactions [1,7–9]. In these cases, the interactions between the adlayer and the substrate, or more specifically, the local variations in that interaction, play a minor role.…”

Substrate Registry in Disordered Layers of Large Molecules

“…As shown previously [31,32] and indicated in Figures 2 a, 3 [31,32] Hence, the values of q can be parameterized as q r,s (phase a) = 458 + r 608 + s 908, where r = 0…2 indicates the domain and s = 0…3 produces the four orientations within each domain.…”

“…[31] The angles could be predicted by a geometric fit model requiring very few system specific details. [32] [a] T. Waldmann, R. These conclusions, however, were based on the orientations found for the molecules within densely packed, ordered arrays, where the lateral interactions also have an aligning effect, at least in a sense that they will favor uniformity.…”

Septipyridines as conformationally controlled substitutes for inaccessible bis(terpyridine)-derived oligopyridines in two-dimensional self-assembly

“…Hydrogen bonding interactions serve this purpose: They are directed, of intermediate strength, and adjustable [3–4]. The bis(terpyridine)-derived oligopyridines (BTPs), are large polyaromatic molecules with C 2 v symmetry, are well established compounds, and are known to self-assemble [5] at the liquid/HOPG [6–11] and at the gas/solid interface [12–14]. Self-assembly also occurs under electrochemical conditions [15], and the molecules assemble into a broad variety of two-dimensional (2D) structures based on weak intermolecular C–H … N hydrogen bonds.…”