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Perez-Hernandez N.,Institute Investigaciones Quimicas CSIC | Febles M.,University of La Laguna | Perez C.,University of La Laguna | Martin J.D.,Institute Investigaciones Quimicas CSIC | Creus A.H.,University of La Laguna
Journal of Physical Chemistry C | Year: 2010

A comparative scanning tunneling microscopy study of the behavior of chemically very similar amphiphilic compounds on Au surfaces is performed. It has been possible to relate different tendencies on a Au(111) single crystal surface to the distinct crystalline supramolecular structures to which the compounds give rise in the solid state. Moreover, the supramolecular hexameric ring that structures the crystal structure of one of the compounds could be identified on the Au surface. This technique has allowed us to obtain a qualitative picture of the aggregation states in solution previous to the nucleation. For the family of the studied compounds, it thus provides information about the likelihood of self-assembling in a particular way in the solid state. © 2010 American Chemical Society.

Perez-Hernandez N.,Institute Investigaciones Quimicas CSIC | Fort D.,Institute Investigaciones Quimicas CSIC | Perez C.,University of La Laguna | Martin J.D.,Institute Investigaciones Quimicas CSIC
Crystal Growth and Design | Year: 2011

We prepared tubular crystals of the hydrated hydroxyl-acid, (1R*,5R*)-7,7-diallyl-5-hydroxymethyl-6-oxabicyclo[3.2.1] octane-1-carboxylic acid, (±)9·2H2O. Crystals grew in a solution of water and carbon tetrachloride under a water vapor atmosphere. These hollow macrocrystals had mostly hexagonal cross sections and were, on average, approximately 5-10 mm in length, with internal diameters in the range of 300-500 μm, and wall thicknesses in the range of 250-400 μm. The experimental results showed that crystal growth was compatible with a lattice defect mechanism, where vacancies corresponded to sub-nano-liquid glassy regions, where water "diffusion" and monomer "dissolution" processes occurred. We propose that the mechanism underlying the formation of the tubular structures is a "build-and-etch" growth process. The etching, or dissolution, started at the middle of each of the basal surfaces of a solid prism and continued along the inside of the long axis; thus, the solid crystals gradually converted into semitubes, which finally became complete hollow tubes. Recrystallization on the external surface was concomitant with the dissolution process; this increased the diameters of the final tubes compared to those of the initial solid prisms.(Figure Presented) © 2011 American Chemical Society.

Guzzi C.,Institute Investigaciones Quimicas CSIC | Munoz-Garcia J.C.,Institute Investigaciones Quimicas CSIC | Enriquez-Navas P.M.,Institute Investigaciones Quimicas CSIC | Rojo J.,Institute Investigaciones Quimicas CSIC | And 2 more authors.
Pure and Applied Chemistry | Year: 2013

The recent introduction of saturation transfer difference (STD) NMR has increased the tools for the study of protein-carbohydrate complexes. This is useful when it is combined with transfer nuclear Overhauser enhancement spectroscopy (NOESY) measurement, or when it is interpreted using the expected calculated values of transference, yielding additional, very valuable information for the study of this type of complex. The objective of this work is to cover the advances of the STD technique as exemplified by the investigations of DC-SIGN (dendritic cell-specific ICAM-3 grabbing non-inte-grin) recognition by simple carbohydrates or mimics of them, based on structures containing a terminal mannose or fucose. We also will discuss the methods for quantification of the STD values based on the initial growing rates with the saturation time. © 2013 IUPAC.

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