The self-assembly of small molecular modules into non-covalently linked polymeric nanostructures is a subject of continuous interest [1]. In particular, supramolecular structures with a high degree of order can be obtained through the self-association of organic molecules on flat solid surfaces. Such structures can be used as scaffolds to position electrically/optically active groups in pre-determined locations in 2D [2] thereby paving the way towards a wide range of applications, e.g. in electronic and optical devices. Among weak interactions, H-bonding offers high control over the process of molecular self-assembly because it combines reversibility, directionality, specificity and cooperativity. Such a unique character is the basis of sophisticated programs for self-assembly such as those based on the Watson–Crick base pairing which directs the formation of the helical structure of DNA. While the self-assembly of guanines into G-quartet based architectures on solid surfaces has been studied by Scanning Tunneling Microscopy (STM) under ultrahigh vacuum (UHV) [3], STM explorations at the solid-liquid interface have been primarily carried out on guanosine derivatives [4]. In this lecture we will present a sub-molecularly resolved STM study at the solid-liquid interface of the metal templated reversible assembly/reassembly process of a N9-alkylguanine into highly ordered quartets and ribbons on highly oriented pyrolitic graphite (HOPG) surfaces. The self-assembly of guanine derivatives on HOPG has been studied as neat component[5] and upon sub-sequent addition of cryptand [2.2.2] molecules, potassium picrate and triflic acid to trigger the reversible interconversion between two different highly ordered supramolecular motifs, i.e. H-bonded ribbon and G-quartet based architectures. In-situ STM imaging provided the first direct evidence on the sub-nm scale of a dynamer operating at surfaces. [6] Finally we will also provide the first example of sub-molecularly resolved vertically oriented switchable chromophores in physisorbed monolayers by monitoring the cis-trans isomerization of a physisorbed azobenzene at surfaces. [7] The nanoscale visualization of such supramolecular interconversion at the solid-liquid interface opens new avenues towards understanding the mechanism of formation and functioning of complex architectures. Furthermore, the in-situ reversible assembly and re-assembly between two highly ordered supramolecular structures at a given surface represents the first step towards the generation of nanopatterned responsive architectures. [1] J. M. Lehn, Science, 295, 2002, 2400. [2] G. P. Spada, S. Lena, S. Masiero, S. Pieraccini, M. Surin, P. Samorì, Adv. Mater., 2008, 20, 2433; A. Ciesielski, L. Piot, P. Samorì, A. Jouaiti, M. W. Hosseini, Adv. Mater., 2009, 21, 1131. [3] R. Otero, M. Schock, L. M. Molina, E. Laegsgaard, I. Stensgaard, B. Hammer, F. Besenbacher, Angew. Chem. Int. Ed., 2005, 44, 2270. [4] G. Gottarelli, S. Masiero, E. Mezzina, S. Pieraccini, J. P. Rabe, P. Samorì, G. P. Spada, Chem. Eur. J., 2000, 6, 3242; T. Giorgi, S. Lena, P. Mariani, M. A. Cremonini, S. Masiero, S. Pieraccini, J. P. Rabe, P. Samorì, G. P. Spada, G. Gottarelli, J. Am. Chem. Soc., 2003, 125, 14741; S. Lena, G. Brancolini, G. Gottarelli, P. Mariani, S. Masiero, A. Venturini, V. Palermo, O. Pandoli, S. Pieraccini, P. Samorì, G. P. Spada, Chem. Eur. J., 2007, 13, 3757. [5] A. Ciesielski, R. Perone, S. Pieraccini, G.P. Spada, P. Samorì, Chem. Commun 2010, 46, 4493. [6] A. Ciesielski, S. Lena, S. Masiero, G. P. Spada, P. Samorì, Angew. Chem. Int. Ed. 2010, 49, 1963. [7] D. Bléger, A. Ciesielski, P. Samorì, S. Hecht, 2010 submitted.

A. Ciesielki, S. Lena, S. Masiero, D. Bléger, S. Hecht, G. P. Spada, et al. (2010). NANOSCALE MONITORING OF RESPONSIVE SUPRAMOLECULAR NANOSTRUCTURES AT THE SOLID-LIQUID INTERFACE. s.l : s.n.

NANOSCALE MONITORING OF RESPONSIVE SUPRAMOLECULAR NANOSTRUCTURES AT THE SOLID-LIQUID INTERFACE

LENA, STEFANO;MASIERO, STEFANO;SPADA, GIAN PIERO;
2010

Abstract

The self-assembly of small molecular modules into non-covalently linked polymeric nanostructures is a subject of continuous interest [1]. In particular, supramolecular structures with a high degree of order can be obtained through the self-association of organic molecules on flat solid surfaces. Such structures can be used as scaffolds to position electrically/optically active groups in pre-determined locations in 2D [2] thereby paving the way towards a wide range of applications, e.g. in electronic and optical devices. Among weak interactions, H-bonding offers high control over the process of molecular self-assembly because it combines reversibility, directionality, specificity and cooperativity. Such a unique character is the basis of sophisticated programs for self-assembly such as those based on the Watson–Crick base pairing which directs the formation of the helical structure of DNA. While the self-assembly of guanines into G-quartet based architectures on solid surfaces has been studied by Scanning Tunneling Microscopy (STM) under ultrahigh vacuum (UHV) [3], STM explorations at the solid-liquid interface have been primarily carried out on guanosine derivatives [4]. In this lecture we will present a sub-molecularly resolved STM study at the solid-liquid interface of the metal templated reversible assembly/reassembly process of a N9-alkylguanine into highly ordered quartets and ribbons on highly oriented pyrolitic graphite (HOPG) surfaces. The self-assembly of guanine derivatives on HOPG has been studied as neat component[5] and upon sub-sequent addition of cryptand [2.2.2] molecules, potassium picrate and triflic acid to trigger the reversible interconversion between two different highly ordered supramolecular motifs, i.e. H-bonded ribbon and G-quartet based architectures. In-situ STM imaging provided the first direct evidence on the sub-nm scale of a dynamer operating at surfaces. [6] Finally we will also provide the first example of sub-molecularly resolved vertically oriented switchable chromophores in physisorbed monolayers by monitoring the cis-trans isomerization of a physisorbed azobenzene at surfaces. [7] The nanoscale visualization of such supramolecular interconversion at the solid-liquid interface opens new avenues towards understanding the mechanism of formation and functioning of complex architectures. Furthermore, the in-situ reversible assembly and re-assembly between two highly ordered supramolecular structures at a given surface represents the first step towards the generation of nanopatterned responsive architectures. [1] J. M. Lehn, Science, 295, 2002, 2400. [2] G. P. Spada, S. Lena, S. Masiero, S. Pieraccini, M. Surin, P. Samorì, Adv. Mater., 2008, 20, 2433; A. Ciesielski, L. Piot, P. Samorì, A. Jouaiti, M. W. Hosseini, Adv. Mater., 2009, 21, 1131. [3] R. Otero, M. Schock, L. M. Molina, E. Laegsgaard, I. Stensgaard, B. Hammer, F. Besenbacher, Angew. Chem. Int. Ed., 2005, 44, 2270. [4] G. Gottarelli, S. Masiero, E. Mezzina, S. Pieraccini, J. P. Rabe, P. Samorì, G. P. Spada, Chem. Eur. J., 2000, 6, 3242; T. Giorgi, S. Lena, P. Mariani, M. A. Cremonini, S. Masiero, S. Pieraccini, J. P. Rabe, P. Samorì, G. P. Spada, G. Gottarelli, J. Am. Chem. Soc., 2003, 125, 14741; S. Lena, G. Brancolini, G. Gottarelli, P. Mariani, S. Masiero, A. Venturini, V. Palermo, O. Pandoli, S. Pieraccini, P. Samorì, G. P. Spada, Chem. Eur. J., 2007, 13, 3757. [5] A. Ciesielski, R. Perone, S. Pieraccini, G.P. Spada, P. Samorì, Chem. Commun 2010, 46, 4493. [6] A. Ciesielski, S. Lena, S. Masiero, G. P. Spada, P. Samorì, Angew. Chem. Int. Ed. 2010, 49, 1963. [7] D. Bléger, A. Ciesielski, P. Samorì, S. Hecht, 2010 submitted.
2010
Guanosines and Quadruplexes
L1
L1
A. Ciesielki, S. Lena, S. Masiero, D. Bléger, S. Hecht, G. P. Spada, et al. (2010). NANOSCALE MONITORING OF RESPONSIVE SUPRAMOLECULAR NANOSTRUCTURES AT THE SOLID-LIQUID INTERFACE. s.l : s.n.
A. Ciesielki; S. Lena; S. Masiero; D. Bléger; S. Hecht; G. P. Spada; P. Samorì
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/97342
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