On-surface polymerization on a semiconducting oxide: aryl halide coupling controlled by surface hydroxyl groups on rutile TiO₂(011)

Abstract

Based on scanning tunneling microscopy experiments, we show that the covalent coupling of aryl halide monomers on the rutile TiO2(011)-(2 × 1) surface is controlled by the density of surface hydroxyl groups. The efficiency of the polymerization reaction depends on the level of surface hydroxylation, but the presence of hydroxyl groups is also essential for the reaction to occur.

On‐Surface Synthesis of Atomically Precise Graphene Nanoribbons

“…Alternatively, one may consider devising a strategy for the direct synthesis on the surface of a semiconductor or insulator. In this case, the catalytic role of the metal needs to be taken over by other mechanisms, such as the interaction with surface hydroxyl groups in the polymerization of aryl halides on the rutile TiO 2 (011) surface [ 72,73 ] or the excitation by UV light in laser-induced polymerization of DBBA on mica. [ 74 ] While this alternative route seems promising, the corresponding efforts are still at an early stage.…”

Ordering of Zn-centered porphyrin and phthalocyanine on TiO2(011): STM studies

“…In the context of adsorption studies, it is important to note that the (110) face of rutile usually contains numerous oxygen vacancies, often filled with hydroxy groups [13]. Those common surface defects are known to have an important effect on the molecule migration and surface diffusion barriers for Pd atoms [14–15], and as demonstrated by Kolmer et al, on the TiO 2 (011)-(2×1) surface, they play a very significant role in on-surface synthesis of polymers [16–17]. In the present work we use a TiO 2 (011)-(2×1) surface, since from our previous reports [5,12,18–22] we know that this rutile face offers higher mobility for molecular building blocks than the (110) one.…”

Porphyrin Metalation at MgO Surfaces: A Spectroscopic and Quantum Mechanical Study on Complementary Model Systems

“…[1], [15]- [17] and references therein),a nd by temperature-programmed desorption. [19][20][21] The effective engineering of hybrid nanomaterials should enable control over their functionalp roperties and activities. Here,w er eport fort he first time an adsorption process at magnesium oxide surfaces that is based on the simultaneous exchange of metal cations from the oxide surfacew ith protons from the molecules.…”

“…This connects to an interesting class of surface phenomena, [5] where-rather than being just spectators-hydroxyl groups stabilize defects as well as adsorbed species on metal oxide surfaces, such as surface-trapped electrons, surface radicals, or other reactives pecies. [19][20][21] The effective engineering of hybrid nanomaterials should enable control over their functionalp roperties and activities. This requires ac lose feedback loop between the generation of metal-oxide-based hybrid structures, to be achieved through the adsorption of functional organic molecules on inorganic substrates, and the in-depth physicochemical characterization of the resulting properties.…”