Guanosine-based hydrogen-bonded 2D scaffolds: metal-free formation of G-quartet and G-ribbon architectures at the solid/liquid interface

Garah, Mohamed El; Perone, Rosaria Carmela; Santana‐Bonilla, Alejandro; Haar, Sébastien; Campitiello, Marilena; Gutiérrez, Rafael; Cuniberti, Gianaurelio; Masiero, Stefano; Ciesielski, Artur; Samorı́, Paolo

doi:10.1039/c5cc03197d

Cited by 38 publications

(32 citation statements)

References 35 publications

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“…30,33,[37][38][39][40] Conversely, when the intermolecular van der Waals interactions are stronger than those between molecules and substrate, the molecules tend to adopt an edge-on configuration. 56 Herein, we present a sub-molecularly resolved STM study on the self-assembly on graphite surface of porphyrins scaffolds functionalized in their meso positions with amide substituents comprising Fc electroactive units. 41 The best strategy to construct edge-on stacked porphyrin-based architectures is to promote the π-π stacking between the aromatic cores.…”

Section: Introductionmentioning

confidence: 99%

Molecular design driving tetraporphyrin self-assembly on graphite: a joint STM, electrochemical and computational study

et al. 2016

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Tuning the intermolecular interactions among suitably designed molecules forming highly ordered self-assembled monolayers is a viable approach to control their organization at the supramolecular level. Such a tuning is particularly important when applied to sophisticated molecules combining functional units which possess specific electronic properties, such as electron/energy transfer, in order to develop multifunctional systems. Here we have synthesized two tetraferrocene-porphyrin derivatives that by design can selectively self-assemble at the graphite/liquid interface into either face-on or edge-on monolayer-thick architectures. The former supramolecular arrangement consists of two-dimensional planar networks based on hydrogen bonding among adjacent molecules whereas the latter relies on columnar assembly generated through intermolecular van der Waals interactions. Scanning Tunneling Microscopy (STM) at the solid-liquid interface has been corroborated by cyclic voltammetry measurements and assessed by theoretical calculations to gain multiscale insight into the arrangement of the molecule with respect to the basal plane of the surface. The STM analysis allowed the visualization of these assemblies with a sub-nanometer resolution, and cyclic voltammetry measurements provided direct evidence of the interactions of porphyrin and ferrocene with the graphite surface and offered also insight into the dynamics within the face-on and edge-on assemblies. The experimental findings were supported by theoretical calculations to shed light on the electronic and other physical properties of both assemblies. The capability to engineer the functional nanopatterns through self-assembly of porphyrins containing ferrocene units is a key step toward the bottom-up construction of multifunctional molecular nanostructures and nanodevices.

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Section: Introductionmentioning

confidence: 99%

Molecular design driving tetraporphyrin self-assembly on graphite: a joint STM, electrochemical and computational study

et al. 2016

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“…Within the lamella, the aromatic cores of Salophens appear as ab right protrusion. Such ah igh contrast of Salophen cores in the STM image is related to their high electronic density.M oreover,n otable features centered in the core of Salophens can be seen, and can be attributed to ferrocene groups adsorbed and immobilized as as econd molecular layer [37] (Figure 2a). The molecular model of 9 presentedi nt he Figure 2b exhibits the spatial distribution of the ferrocene units (in blue color) matching to the molecular packingp ortrayed from the STM image.…”

Section: Surface Modificationstudies With Salophen Derivativesmentioning

confidence: 99%

Phenoxyaluminum(salophen) Scaffolds: Synthesis, Electrochemical Properties, and Self‐Assembly at Surfaces of Multifunctional Systems

Mengozzi

Garah

Gualandi

et al. 2018

Chemistry A European J

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Salophens and Salens are Schiff bases generated through the condensation of two equivalents of salicylaldehyde with either 1,2-phenylenediamines or aliphatic diamines, respectively. Both ligands have been extensively exploited as key building blocks in coordination chemistry and catalysis. In particular, their metal complexes have been widely used for various catalytical transformations with high yield and selectivity. Through the modification of the phenol unit it is possible to tune the steric hindrance and electronic properties of Salophen and Salen. The introduction of long aliphatic chains in salicylaldehydes can be used to promote their self-assembly into ordered supramolecular structures on solid surfaces. Herein, we report a novel method towards the facile synthesis of robust and air-stable [Al(Salophen)] derivatives capable of undergoing spontaneous self-assembly at the graphite/solution interface forming highly-ordered nanopatterns. The new synthetic approach relies on the use of [MeAl (Salophen)] as a building unit to introduce, via a simple acid/base reaction with functionalized acidic phenol derivatives, selected frameworks integrating multiple functions for efficient surface decoration. STM imaging at the solid/liquid interface made it possible to monitor the formation of ordered supramolecular structures. In addition, the redox properties of the Salophen derivatives functionalized with ferrocene units in solution and on surface were unraveled by cyclic voltammetry. The use of a five-coordinate aluminum alkyl Salophen precursor enables the tailoring of new Salophen molecules capable of undergoing controlled self-assembly on HOPG, and thereby it can be exploited to introduce multiple functionalities with subnanometer precision at surfaces, ultimately forming ordered functional patterns.

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“…Unfortunately, the designed molecules were non capable of self‐assembling on HOPG. Luckily, by a slight modification of guanosine, the ability to prepare an ordered structure on HOPG was observed 65. The need for new molecules containing ferrocene, able to control their arrangement on HOPG, has stimulated other design and synthetic efforts.…”

Section: Carbenium Ion For Qcamentioning

confidence: 99%

From QCA (Quantum Cellular Automata) to Organocatalytic Reactions with Stabilized Carbenium Ions

Gualandi

Mengozzi

Manoni

et al. 2016

The Chemical Record

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What do quantum cellular automata (QCA), "on water" reactions, and SN 1-type organocatalytic transformations have in common? The link between these distant arguments is the practical access to useful intermediates and key products through the use of stabilized carbenium ions. Over 10 years, starting with a carbenium ion bearing a ferrocenyl group, to the 1,3-benzodithiolylium carbenium ion, our group has exploited the use of these intermediates in useful and practical synthetic transformations. In particular, we have applied the use of carbenium ions to stereoselective organocatalytic alkylation reactions, showing a possible solution for the "holy grail of organocatalysis". Examples of the use of these quite stabilized intermediates are now also considered in organometallic chemistry. On the other hand, the stable carbenium ions are also applied to tailored molecules adapted to quantum cellular automata, a new possible paradigm for computation. Carbenium ions are not a problem, they can be a/the solution!

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Guanosine-based hydrogen-bonded 2D scaffolds: metal-free formation of G-quartet and G-ribbon architectures at the solid/liquid interface

Cited by 38 publications

References 35 publications

Molecular design driving tetraporphyrin self-assembly on graphite: a joint STM, electrochemical and computational study

Molecular design driving tetraporphyrin self-assembly on graphite: a joint STM, electrochemical and computational study

Phenoxyaluminum(salophen) Scaffolds: Synthesis, Electrochemical Properties, and Self‐Assembly at Surfaces of Multifunctional Systems

From QCA (Quantum Cellular Automata) to Organocatalytic Reactions with Stabilized Carbenium Ions

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