Publicaciones 2011-2020

@article{orellana2017palmitic,
title = {Palmitic Acid and Hexadecylamine Molecules Assdsorbed on Titania Surface in Hybrid Composites. Effect of Surfactants Using Density Functional Theory},
author = { C. Orellana and F. Mendizabal and G. Gonz\'{a}lez and S. Miranda-Rojas and L. Barrientos-Poblete},
url = {/brokenurl#<Go to ISI>://WOS:000401679900007},
doi = {10.1016/j.comptc.2017.04.006},
issn = {2210-271x},
year = {2017},
date = {2017-01-01},
journal = {Computational and Theoretical Chemistry},
volume = {1110},
pages = {50-59},
publisher = {2017 Elsevier B.V.},
abstract = {A complete theoretical characterization of the factors involved in the stabilization of hybrid laminar composites is reported, with the purpose of understanding the main interactions involved in the formation of these types of systems. The models were built using two different surfactants: hexadecylamine (HDA) and palmitic acid (PAc), on a cluster of titania (TiO2) which represents its anatase crystalline phase. We explored the relevance of the titania-surfactant and surfactant-surfactant interactions, and of the protonation state of the palmitic acid in the stabilization of the hybrid laminar composites. The results were rationalized using energy decomposition analysis (EDA) and the non-covalent interaction index (NIC). The interaction energies between HDA and the TiO2 surface without the contribution of the dispersion forces were -25 kcal/mol and -29 kcal/mol for the (1 0 0) and (1 01) surfaces, respectively. These results suggest the formation of a donor-acceptor bond between HDA-TiO2 allowing its stabilization. On the other hand, the interaction energy between PAc and the TiO2 (1 0 1) surface was about -45 kcal/mol without the dispersion term. Thus, the PAc-TiO2 model has a higher covalent character than the HDA-TiO2 interaction, as confirmed by the energy decomposition analyses. The results suggest new hybrid laminar composites which are better when carboxylic acid was used instead of amines. Therefore, the use of surfactants with the carboxyl functional group yielded more stable TiO2 hybrid composites. The interaction energy between surfactant chains was about -13 kcal/mol, confirming the importance of dispersion forces in the stabilization of these types of systems. The study of systems with palmitic acid was complemented by building some anionic models to show the importance of acid protons in those systems. However, when the acidic hydrogens were removed, the interaction energy between the PAc molecules considering the dispersion correction increased to 45 kcal/mol, with a highly repulsive character. These results suggest that the acid hydrogens of the PAc surfactants play a fundamental role in terms of correctly representing the carboxylic acid-TiO2 interface and the stabilization of the laminar hybrid composites.},
keywords = {basis-sets, bsse, calculations, catalysis, clusters, compounds, dft dft, dioxide dispersion enzymatic hexadecylamine, hydrogen-bonds, interactions, laminar n-body noncovalent palmitic photocatalysis properties, sensitized solar-cells, spectroscopic strong term, tio2, titanium},
pubstate = {published},
tppubtype = {article}
}

@article{RN301,
title = {Evidence of the Disassembly of Alpha-Cyclodextrin-Octylamine Inclusion Compounds Conjugated to Gold Nanoparticles Via Thermal and Photothermal Effects},
author = { N. Silva and S. Moris and M. Diaz and N. Yutronic and E. Lang and B. Chornik and M.J. Kogan and P. Jara},
url = {/brokenurl#<Go to ISI>://WOS:000389918200026},
doi = {10.3390/molecules21111444},
year = {2016},
date = {2016-01-01},
journal = {Molecules},
volume = {21},
number = {11},
abstract = {Cyclodextrin (CD) molecules form inclusion compounds (ICs), generating dimers that are capable of encapsulating molecules derived from long-chain hydrocarbons. The aim of this study is to evaluate the structural changes experienced by ICs in solution with increasing temperatures. For this, a nuclear magnetic resonance (H-1-NMR) titration was performed to determinate the stoichiometric alpha-cyclodextrin (alpha-CD):octylamine (OA) 2:1 and binding constant (k = 2.16 M-2) of ICs. Solution samples of alpha-CD-OA ICs conjugated with gold nanoparticles (AuNPs) were prepared, and H-1-NMR spectra at different temperatures were recorded. Comparatively, H-1-NMR spectra of the sample irradiated with a laser with tunable wavelengths, with plasmons of conjugated AuNPs, were recorded. In this work, we present evidence of the disassembly of ICs conjugated with AuNPs. Thermal studies demonstrated that, at 114 degrees C, there are reversible rearrangements of the host and guests in the ICs in a solid state. Migration movements of the guest molecules from the CD cavity were monitored via temperature-dependent H-1-NMR, and were verified comparing the chemical shifts of octylamine dissolved in deuterated dimethylsulfoxide (DMSO-d(6)) with the OA molecule included in alpha-CD dissolved in the same solvent. It was observed that, at 117 degrees C, OA exited the alpha-CD cavity. CD IC dimer disassembly was also observed when the sample was irradiated with green laser light.},
keywords = {beta-cyclodextrin, complex, compounds, constants, core crystals, cyclodextrin, effects, gold inclusion nanoparticles, octylamine, photothermal},
pubstate = {published},
tppubtype = {article}
}

@article{RN137,
title = {Adhesion of Gold and Silver Nanoparticles onto Urea-Alkylamine Inclusion Compounds},
author = { C. Campos and M. Munoz and L. Barrientos-Poblete and E. Lang and P. Jara and I. Sobrados and N. Yutronic},
url = {/brokenurl#<Go to ISI>://WOS:000314898300018},
doi = {10.1007/s10847-012-0157-1},
issn = {1388-3127},
year = {2013},
date = {2013-01-01},
journal = {Journal of Inclusion Phenomena and Macrocyclic Chemistry},
volume = {75},
number = {1-2},
pages = {165-173},
abstract = {We report the synthesis and characterization of a new series of urea inclusion compounds containing primary alkylamine (octyl, decyl and dodecyl) as guests, as well as the deposition of gold and silver nanoparticles onto the crystalline surface of these complexes. X-ray diffraction confirms the inclusion process of the amine in the urea cavities. The structures determined for the three complexes correspond to a hexagonal channel structure with space group P6(1)22. Alkylamine-urea stoichiometric ratios in all cases satisfy the relationship 1:3n (n = 2 for octylamine and 3 for decylamine and dodecylamine), determined by elemental analysis. The deposition of gold and silver nanoparticles by the magnetron sputtering technique onto microcrystals of the complexes was analyzed by Diffuse Reflectance Spectroscopy, showing characteristic surface plasmon resonance for metal nanoparticles. Transmission electron microscopy demonstrates the presence of metal nanoparticles (MNPs) in a size range between 5 and 60 nm for gold and between 5 and 20 nm for silver, and furthermore, in some cases it shows vestiges of a hexagonal arrangement of the MNPs. X-ray diffraction and IR measurements demonstrate that the basic structure of the matrix remains unchanged after the MNPs adhesion. IR also shows increased broadening and intensity of the characteristic NH2 bending frequencies (1,597 cm(-1)) when the MNPs interact with the inclusion compounds. We conclude that the interactions between the inclusion compounds and metal nanoparticles occurs mainly through the amino groups of the guest molecules that can emerge from the entrance of the inclusion compound cavities attracted by the metallic nanoparticles, in opposition to the restoring van der Waals interactions present inside channels, which increase with increasing chain length of the guest molecules., Schematic representation of urea inclusion compounds containing primary alkylamine (octyl, decyl and dodecyl) as guests and the deposition of gold and silver nanoparticles onto the crystalline surface of these complexes.},
keywords = {alpha-cyclodextrin, amine aspects, compounds, dynamics gold guests, inclusion molecules, nanoparticle, nanoparticles, reduction, silver structural temperature, thiourea, urea x-ray-diffraction},
pubstate = {published},
tppubtype = {article}
}

@article{RN138,
title = {Selective Nanodecoration of Modified Cyclodextrin Crystals with Gold Nanorods},
author = { B. Herrera and C. Adura and N. Yutronic and M.J. Kogan and P. Jara},
url = {/brokenurl#<Go to ISI>://WOS:000310763900006},
doi = {10.1016/j.jcis.2012.08.027},
issn = {0021-9797},
year = {2013},
date = {2013-01-01},
journal = {Journal of Colloid and Interface Science},
volume = {389},
pages = {42-45},
publisher = {2012 Elsevier Inc.},
abstract = {Gold nanorods (AuNRs) stabilized by cetyltrimethylammonium bromide (CTAB) were deposited onto crystals of alpha-cyclodextrin (alpha-CD) inclusion compounds (ICs) that contained octanethiol (OT) as guest molecules. The nanodecoration was produced specifically at the 001 crystal planes through interaction between the -SH groups of the ICs and the AuNRs.},
keywords = {alpha-cyclodextrin, cationic complex compound, compounds, cyclodextrin, deposition, gold inclusion nanodecoration, nanoparticles, nanorods, surfactants},
pubstate = {published},
tppubtype = {article}
}

@article{RN97,
title = {Vibrational and Scaled Quantum Chemical Study of O,O-Dimethyl S-Methylcarbamoylmethyl Phosphorodithioate, Dimethoate},
author = { G. Diaz-Fleming and F. Celis and A. Aracena and M. Campos-Vallette and A.E. Aliaga and R. Koch},
url = {/brokenurl#<Go to ISI>://WOS:000301471600032},
doi = {10.1016/j.saa.2011.12.032},
issn = {1386-1425},
year = {2012},
date = {2012-01-01},
journal = {Spectrochimica Acta Part a-Molecular and Biomolecular Spectroscopy},
volume = {89},
pages = {222-230},
publisher = {2011 Elsevier B.V.},
abstract = {Infrared and Raman spectra of O,O-dimethyl S-methylcarbamoylmethylphosphorodithioate, dimethoate, have been recorded. Density functional theory, DFT, with the B3LYP functional was used for the optimization of the ground state geometry and simulation of the infrared and Raman spectra of this molecule. Calculated geometrical parameters fit very well with the experimental ones. Based on the recorded data, the DFT results and a normal coordinate analysis based on a scaled quantum mechanical (SQM) force field approach, a complete vibrational assignment was made for the first time.},
keywords = {analysis, assignment basis, calculations, compounds, coordinate dft dimethoate, field, force force-constants, gaussian-type infrared, infrared-spectra, methods, molecular-orbital monosubstituted normal organic-molecules, phosphorus raman, sqm},
pubstate = {published},
tppubtype = {article}
}