Célia Fonseca Guerra

Publications (108) View all

• Article: Supramolecular H-bonded Porous Networks at Surfaces: Exploiting Primary and Secondary Interactions in a Bi-component Melamine-Xanthine System

  A. Ciesielski, S. Haar, G. Paragi, Z. Kupihár, Z. Kele, S. Masiero, C. Fonseca Guerra, F. M. Bickelhaupt, G.P. Spada, L. Kovács, P. Samorì
  Physical Chemistry Chemical Physics 01/2013; · 3.57 Impact Factor
• Article: Solvent Effects on Hydrogen Bonds in Watson-Crick, Mismatched, and Modified DNA Base Pairs

  J. Poater, M. Swart, C. Fonseca Guerra, F. M. Bickelhaupt
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  ABSTRACT: We have theoretically analyzed a complete series of Watson–Crick and mismatched DNA base pairs, both in gas phase and in solution. Solvation causes a weakening and lengthening of the hydrogen bonds between the DNA bases because of the stabilization of the lone pairs involved in these bonds. We have also shown that chlorouracil can mimic the behavior of thymine, and thus perfectly incorporate into a DNA strand, in nice agreement with recent experiments involving Escherichia coli. Moreover, through quantitative bond analyses in the framework of Kohn–Sham DFT, we have further consolidated the notion that donor–acceptor orbital interactions between lone-pairs and N–H σ* orbitals contribute in the same order of magnitude to the hydrogen-bond strength as electrostatic interactions.
  Computational and Theoretical Chemistry 01/2013; 998:57-63.
• Chapter: Guanine, Xanthine and Uric Acid Assemblies: Comparative Theoretical and Experimental Studies

  G. Paragi, J. Szolomajer, Z. Kupihar, G. Batta, Z. Kele, P. Padar, B. Penke, H. Zijlstra, C. Fonseca Guerra, F. M. Bickelhaupt, L. Kovacs
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  ABSTRACT: An important part in studying Quadruplexes is via theoretical modeling, analysis and prediction. This primarily provides a theoretical background of basic self-assembly processes through which structural and electronic properties of example molecular devices can be calculated. Combined with experimental results, such studies help in predicting new properties and design novel of novel materials. The folding of G-quadruplexes is directed by controllable factors. The structural basis underlying the precise relationship between DNA sequences and folding into quadruplexes has been investigated towards prediction of structural folds. The theoretical modeling and analysis includes a variety of methods that span from ab initio quantum chemical techniques to classical molecular dynamics. Different computer-based methodologies have been used to study structural properties of quadruplexes with main emphasis on biological applications and drug discovery. Development of multi-scale approaches to treat different theory levels can aid in studying different parts of complex devices (molecule, surface, solution, electrodes etc.).
  01/2013: pages 179-193; , ISBN: 978-1-84973-695-4
• Article: Self-assembly of N3-substituted xanthines in the solid state and at the solid-liquid interface.

  Artur Ciesielski, Sebastien Haar, Attila Bényei, Gabor Paragi, C Fonseca Guerra, F Matthias Bickelhaupt, Stefano Masiero, János Szolomájer, Paolo Samori, Gian Piero Spada, Lajos Kovács
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  ABSTRACT: Self-assembly of small molecular modules interacting through non-covalent forces is increasingly being used to generate functional structures and materials for electronic, catalytic, and biomedical applications. The greatest control over the geometry in H-bond supramolecular architectures, especially in H-bonded supramolecular polymers, can be achieved by exploiting the rich programmability of artificial nucleobases undergoing self-assembly through strong H-bonds. Here N3-functionalized xanthine modules are described, which are capable of self-associating through self-complementary H-bonding patterns to form H-bonded supramolecular ribbons. The self-association of xanthines through directional H-bonding between neighboring molecules allows the controlled generation of highly compact 1D supramolecular polymeric ribbons on graphite. These architectures have been characterized by scanning tunneling microscopy at the solid-liquid interface, corroborated by dispersion-corrected density functional theory (DFT) studies and X-ray diffraction.
  Langmuir 01/2013; · 4.19 Impact Factor
• Article: Self-assembly of N3-substituted xanthines in the solid state and at the solid-liquid interface

  A. Ciesielski, S. Haar, A. Bényei, G. Paragi, C. Fonseca Guerra, F. M. Bickelhaupt, S. Masiero, J. Szolomájer, P. Samorì, G. P. Spada, L. Kovács
  [show abstract] [hide abstract]
  ABSTRACT: Self-assembly of small molecular modules interacting through non-covalent forces is increasingly being used to generate functional structures and materials for electronic, catalytic, and biomedical applications. The greatest control over the geometry in H-bond supramolecular architectures, especially in H-bonded supramolecular polymers, can be achieved by exploiting the rich programmability of artificial nucleobases undergoing self-assembly through strong H-bonds. Here N3-functionalized xanthine modules are described, which are capable of self-associating through self-complementary H-bonding patterns to form H-bonded supramolecular ribbons. The self-association of xanthines through directional H-bonding between neighboring molecules allows the controlled generation of highly compact 1D supramolecular polymeric ribbons on graphite. These architectures have been characterized by scanning tunneling microscopy at the solid–liquid interface, corroborated by dispersion-corrected density functional theory (DFT) studies and X-ray diffraction.
  Langmuir 01/2013; · 4.19 Impact Factor