Publicaciones 2011-2020

@article{RN395,
title = {Solution, Solid-State Two Step Synthesis and Optical Properties of Zno and Sno2 Nanoparticles and Their Nanocomposites with Sio2},
author = { C. Diaz and M.L. Valenzuela and M. Segovia and K. Correa and R. De La Campa and A.P. Soto},
url = {/brokenurl#<Go to ISI>://WOS:000425608200006},
doi = {10.1007/s10876-017-1324-8},
issn = {1040-7278},
year = {2018},
date = {2018-01-01},
journal = {Journal of Cluster Science},
volume = {29},
number = {2},
pages = {251-266},
abstract = {Nanostructure luminescent ZnO and SnO2 materials are prepared by a two-step solid-state method based on the solution preparation of the macromolecular precursors ZnCl2 center dot Chitosan and SnCl2 center dot Chitosan having different ratios (1:1, 1:5 and 1:10), their pyrolysis under air at 800 A degrees C. The pyrolytic ZnO and SnO2 nanomaterials show a dependence of the particle size, morphology and luminescent properties with the ratio [metal/polymer] in the MCl2 center dot Chitosan precursors. Thus, ZnO semiconductor materials exhibit luminescence spectra with several emission at 440 nm corresponds to a radiative transition of an electron from the shallow donor level of oxygen vacancies, and the zinc interstitial, to the valence band. On the other hand, the photoluminescence spectrum of the nanostructured SnO2 shows an intense blue luminescence at a wavelength of 420 nm which may be attributed to oxygen-related defects that have been introduced during the growth process of the nanoparticles. Additionally, whereas SnO2 was successfully incorporated into SiO2 structure (SnO2//SiO2) by pyrolysis of solid-state mixtures of the precursors SnCl2 center dot Chitosan in the presence of SiO2, the same reaction carried out with ZnCl2 center dot Chitosan precursors led to a mixture of Zn2SiO4 and SiO2. Thus, this new methodology yields nanostructured semiconductor materials, ZnO and SnO2, suitable for optoelectronic and sensor solid-state devices.},
keywords = {center chitin, chitosan, crystal-structure, dot fine-structure, kinetics, mechanisms, nanostructures, photoluminescence, sio2, size sno2 solid-state synthesis, zinc-oxide, zno},
pubstate = {published},
tppubtype = {article}
}

@article{RN403,
title = {Inhibiting Pathogen Surface Adherence by Multilayer Polyelectrolyte Films Functionalized with Glucofuranose Derivatives},
author = { V. Villalobos and A. Leiva and H. Rios and J. Pavez and C.P. Silva and M. Ahmar and Y. Queneau and J.M. Blamey and F.P. Chavez and M. Urz\'{u}a},
url = {/brokenurl#<Go to ISI>://WOS:000442706600064},
doi = {10.1021/acsami.8b03605},
issn = {1944-8244},
year = {2018},
date = {2018-01-01},
journal = {Acs Applied Materials & Interfaces},
volume = {10},
number = {33},
pages = {28147-28158},
abstract = {Inhibiting pathogenic bacterial adherence on surfaces is an ongoing challenge to prevent the development of biofilms. Multilayer polyelectrolyte films are feasible antibacterial materials. Here, we have designed new films made of carbohydrate polyelectrolytes to obtain antibacterial coatings that prevent biofilm formation. The polyelectrolyte films were constructed from poly(maleic anhydride-alt-styrene) functionalized with glucofuranose derivatives and quaternized poly(4-vinylpyridine) N-alkyl. These films prevent Pseudomonas aeruginosa and Salmonella Typhimurium, two important bacterial contaminants in clinical environments, from adhering to surfaces. When the film was composed of more than 10 layers, the bacterial population was greatly reduced, while the bacteria remaining on the film were morphologically damaged, as atomic force microscopy revealed. The antibacterial capacity of the polyelectrolyte films was determined by the combination of thickness, wettability, surface energy, and most importantly, the conformation that polyelectrolytes adopt the function of nature of the carbohydrate group. This polyelectrolyte film constitutes the first green approach to preventing pathogenic bacterial surface adherence and proliferation without killing the bacterial pathogen.},
keywords = {antibacterial bacterial, biofilm biomaterials, carbohydrate challenges coatings, construction, formation, inhibition, mechanisms, p. polyelectrolytes, resistance, s. surfaces, typhimurium},
pubstate = {published},
tppubtype = {article}
}

@article{RN255,
title = {Crystallizing Vanadium Pentoxide Nanostructures in the Solid-State Using Modified Block Copolymer and Chitosan Complexes},
author = { C. Diaz and G. Barrera and M. Segovia and M.L. Valenzuela and M. Osiak and C. O'dwyer},
url = {/brokenurl#<Go to ISI>://WOS:000354681800001},
doi = {10.1155/2015/105157},
issn = {1687-4110},
year = {2015},
date = {2015-01-01},
journal = {Journal of Nanomaterials},
volume = {10.1155/2015/105157},
abstract = {A systematic study of the synthesis of V2O5 nanostructured materials using macromolecular PS-co-4-PVP center dot(VCl3)(y) and chitosan center dot(VCl3)(y) complexes is presented. It is demonstrated that various coordination degrees of the metal into the polymeric chain specifically influence the product formation after pyrolysis. PS-co-4-PVP center dot(VCl3)(y) and chitosan center dot(VCl3)(y) complexes were prepared by simple coordination reaction of VCl3 with the respective polymer inmolar ratios 1 : 1, 1 : 5, and 1 : 10 metal/polymer and characterized by elemental analysis, IR spectroscopy, and TGA/DSC analysis. Solid-state thermolysis of these precursors at several temperatures under air results in nanostructured V2O5 using all precursors. The size and shape of the nanostructured V2O5 depend on the nature of the polymer. For the chitosan center dot(VCl3)(y) precursors sub-10nm nanocrystals are formed. The calcination process, involved in the preparation method, produces V2O5 with photoluminescence in the visible light region, suggesting the possible application in oxygen sensing devices.},
keywords = {electrochemical gold growth, intercalation, mechanisms, nanocomposites, nanoparticles, optical-properties, photoluminescence, precursors, properties, ruthenium},
pubstate = {published},
tppubtype = {article}
}

@article{RN103,
title = {Predicting the Reaction Mechanism of Nucleophilic Substitutions at Carbonyl and Thiocarbonyl Centres of Esters and Thioesters},
author = { R. Ormazabal-Toledo and E.A. Castro and J.G. Santos and D. Millan and A. Canete and R. Contreras and P.R. Campodonico},
url = {/brokenurl#<Go to ISI>://WOS:000313125800038},
doi = {10.1002/poc.3048},
issn = {0894-3230},
year = {2012},
date = {2012-01-01},
journal = {Journal of Physical Organic Chemistry},
volume = {25},
number = {12},
pages = {1359-1364},
publisher = {2012 John Wiley & Sons, Ltd.},
abstract = {In nucleophilic substitution reactions at carbonyl centres, there are two possible channels. The first one occurs when the attack of nucleophilic agents takes place simultaneously with the departure of the nucleofuge. This process is named as concerted. The second possibility is the formation of a reaction intermediate, typically a tetrahedral intermediate from which the nucleofuge departs after passing through a second transition state. This second mechanism is defined as stepwise. Whether a concerted or stepwise mechanism is to be expected for a given reaction depends on several factors. Among these determinants are the nucleophilicity of the attacking group, the leaving group ability of the nucleofuge, and the solvent, which affects both the stability of the intermediate or the transition states involved. The role of the electrophilic centre can however become an important factor that can determine the reaction mechanism. In this work we show that the group nucleophilic Fukui function model may be used to rationalize and to predict the reaction mechanism of the title compounds towards alicyclic amines. In general, when the electrophilic carbon centre is attached to the soft sulfur atom, the reaction mechanism is predicted to follow a stepwise route. When the electrophilic carbon atom is attached to a harder oxygen centre, the reaction mechanism is determined by chemical substitution at the nucleofuge moiety. Experimental verification for a set of four substrates is presented.},
keywords = {aminolysis, carbonyl carboxylic center, contrasting density derivatives, dithiocarbonates, electron electrophilic esters, fukui function, group group, kinetic kinetics, leaving measurements, mechanisms, o-ethyl phenyl, reaction reactivity, reorganization, secondary},
pubstate = {published},
tppubtype = {article}
}