Conformation Controls Mobility: 2H‐Tetranaphthylporphyrins on Cu(111)

Abstract

The adsorption behavior and the mobility of 2H‐Tetranaphthylporphyrin (2HTNP) on Cu(111) was investigated by scanning tunneling microscopy (STM) at room temperature (RT). The molecules adsorb, like the structurally related 2HTPP, in the “inverted” structure with the naphthyl plane restricted to an orientation parallel to the Cu surface. The orientation of the four naphthyl groups yields altogether 16 possible conformations. Due to the existence of rotamer pairs, 10 different appearances are expected on the surface, and all of them are identified by STM at RT. Most interestingly, the orientation of the naphthyl groups significantly influences the diffusion behavior of the molecules on Cu(111). We identify three different groups of conformers, which are either immobile, medium or fast diffusing at RT. The mobility seems to decrease with increasing size of the footprint of the conformers on the surface.

Structure and Conformation of Individual Molecules upon Adsorption of a Mixture of Benzoporphyrins on Ag(111), Cu(111), and Cu(110) Surfaces

“…This appearance is clearly different from the appearance of the molecules in the stripe phase on Cu(111). It is, however, similar to the appearance of 2H‐tetraphenylporphyrins (2H‐TPP) and 2H‐tetranaphthylporphyrins (2H‐TNP) on Cu(111), [23,34] which both have an inverted structure with two pyrrole groups oriented nearly perpendicular to the surface. From this similarity, we propose an inverted structure also for 2H‐diTTBP(x)BPs on Cu(110).…”

“…This appearance is clearly different from the appearance of the molecules in the stripe phase on Cu(111). It is, however, similar to the appearance of 2H-tetraphenylporphyrins (2H-TPP) and 2Htetranaphthylporphyrins (2H-TNP) on Cu(111), [23,34] which both ChemPhysChem Figure 7. STM images of 2H-diTTBP(x)BPs on Cu(110), as an overview (left, 50 × 50 nm 2 ), with close-up (right, 20 × 20 nm 2 ), and with high resolution (bottom left three, 2.5 × 1.86 nm 2 ; bottom-right, 2.5 × 2.5 nm 2 ), measured at RT.…”

On-Surface Synthesis of Rigid Benzenoid- and Nonbenzenoid-Coupled Porphyrin–Graphene Nanoribbon Hybrids

“…The nc-AFM images (Figure a) reveal two opposing pyrrole groups tilted upward, going in hand with a downward tilting of the naphthalenes, attributed to steric hindrance at the crowded naphthalene–pyrrole positions (gray circles Figure a). Indeed, significant distortions from planarity were reported for closely related β, meso -fused extended porphyrins, based on NMR and X-ray analyses. , Furthermore, such saddle-shaped macrocycle deformations are characteristic of functionalized porphyrins on Au(111) and Ag(111) surfaces. − Though there have been studies on naphthyl-functionalized porphyrins, , to our knowledge, Figure a provides the first experimental structural characterization of an individual porphyrin fused with naphthalenes, representing archetypical polycyclic aromatic hydrocarbons.…”

“…38,53 Furthermore, such saddle-shaped macrocycle deformations are characteristic of functionalized porphyrins on Au(111) and Ag(111) surfaces. 54−56 Though there have been studies on naphthyl-functionalized porphyrins, 57,58 to our knowledge, Figure 1a provides the first experimental structural characterization of an individual porphyrin fused with naphthalenes, representing archetypical polycyclic aromatic hydrocarbons. The oligomerization is induced by debromination of the naphthalenes, followed by C−C aryl−aryl coupling.…”

Estudo da adsorção, conformação e reatividade de porfirinas brominadas em Cu(111)

“…Além disso, o entendimento acerca dessas moléculas, em seu sentido mais fundamental, proporciona um controle preciso na construção de nanoestruturas e também caminhos para a aplicação destas moléculas. Podemos citar como exemplo a mudança conformacional da molécula ao interagir com um substrato, onde ela passa por mudanças estruturais intramoleculares que podem aumentar ou diminuir a barreira de energia para difusão entre sítios de adsorção da superfície [11]. Ou ainda pela funcionalização do macrociclo, que pode tornar a molécula mais sensível a gases ou à luz, visando aplicações em sensores e dispositivos fotônicos [12].…”