Publicaciones 2011-2020

@article{RN87,
title = {Sol-Gel Incorporation of Organometallic Compounds into Silica: Useful Precursors to Metallic Nanostructured Materials},
author = { C. Diaz and M.L. Valenzuela and D. Garrido and P. Aguirre},
url = {/brokenurl#<Go to ISI>://WOS:000305169800021},
issn = {0717-9707},
year = {2012},
date = {2012-01-01},
journal = {Journal of the Chilean Chemical Society},
volume = {57},
number = {2},
pages = {1155-1162},
abstract = {Inclusion of the organometallic MLn = [HOC5H4N center dot Cp2TiCl][PF6] (I), HOC5H4N center dot W(CO)(5) (2), HOC5H4N center dot Mo(CO)(5) (3), [HOC6H4CH2CN center dot Cp2TiCl][PF6] (4), HOC6H4CH2CN center dot W(CO)(5) (5) and HOC6H4CH2CN center dot Mo(CO)(5) (6) into amorphous silica using the gelator precursor TEOS and N3P3N-H[CH2](3)Si[OEt](3)(6) afford the gels (MLn)(SiO2)(n). The inorganic-organic hybrid nanocomposites were pyrolyzed under air at 800 degrees C to give nanostructured metal oxides and/or metal pyrophosphates (phosphates) included in the silica matrices. The morphology of the monolithic nanocomposites exhibited a strong dependence on the gel precursor used being mainly laminar for those prepared using N2P3NH[CH2](3)Si[OEt](3) as gelator. TEm images show different shape and size such as circular nanoparticles, nanocables and agglomerates in some cases with sizes of 20 nm for the circular nanostructures, and diameter about 25 nm for the nanocables.},
keywords = {bridged magnetic-properties, materials, matrix, mesoporous molecular nanoclusters nanocomposites, nanoparticles, nanostructured, nanowires, organic-inorganic polysilsesquioxanes, precursors, pyrophosphates, silica, sol-gel, source thermolytic transformation},
pubstate = {published},
tppubtype = {article}
}

@article{RN88,
title = {The Inclusion of Organometallic Derivatives of Cyclotriphosphazenes inside Sio2 Matrix and Their Conversion to Nanostructured Metal-Oxides and Phosphates},
author = { C. Diaz and M.L. Valenzuela and D. Carrillo and J. Riquelme and R. Diaz},
url = {/brokenurl#<Go to ISI>://WOS:000307754600022},
doi = {10.1007/s10904-012-9692-x},
issn = {1574-1443},
year = {2012},
date = {2012-01-01},
journal = {Journal of Inorganic and Organometallic Polymers and Materials},
volume = {22},
number = {5},
pages = {1101-1112},
abstract = {Organometallic derivatives of the cyclotriphosphazene N3P3[OC6H4CH2CN center dot TiClCp2](6) (1), N3P3(O6H5)(5)[OC6H4N center dot W(CO)(5)] (2), N3P3[OC6H4CH2CN center dot Mo(CO)(5)](6) (3), [N3P3(O6H5)(5)(OC5H4N center dot CpRu(PPh3)(2))][PF6] (4), [N3P3(O2C12H8)(2)OC5H4N center dot Ag(PPh3)][OSO2CF3] (5), N3P3[OC6H5](5) [OC5H4N center dot Cu][PF6] (6) and N3P3[OC6H4CH2CN center dot CuCl](6)[PF6](6) (7),were incorporated inside SiO2 through the sol-gel method. The metal-organic nanocomposites of the general formula N3P3[OC6H4CH2CN center dot TiClCp2](6)center dot nSiO(2) (G (1) ), N3P3[OC6H4N center dot W(CO)(5)]center dot nSiO(2) (G (2) ), N3P3[OC6H4CH2CN center dot Mo(CO)(5)](6)center dot nSiO(2) (G (3) ), N3P3(O6H5)(5)OC5H4N center dot CpRu(PPh3)(2)][PF6]center dot nSiO(2) (G (4) ), [N3P3(O2C12H8)(2)OC5H4N center dot Ag(PPh3)][OSO2CF3]center dot nSiO(2) (G (5) ), N3P3[OC6H5](5)[OC5H4N center dot Cu][PF6]center dot(SiO2) (n) (G (6) ), and N3P3[OC6H4CH2CN center dot CuCl](6)[PF6](6)center dot(SiO2) (n) (G (7) ), were characterized by IR spectroscopy; C-12, (31) P and Si-29 MAS NMR measurements as well as UV-Visible diffuse reflectance spectra, indicating the presence of the respective organometallic derivatives of the cyclotriphosphazene incorporated into SiO2. Pyrolysis of these nanocomposites under air at 800 A degrees C gives rise to nanostructured metal-oxides and metal phosphates incorporated into amorphous SiO2, with the presence in some cases of complexes phase mixtures. From some precursors, we obtained metal-oxides/phosphates nanoparticles separated from the SiO2 nanoparticles instead the oxides/phosphates nanoparticles inside the SiO2 matrix. Additionally and for comparison purposes, we used the compound N3P3[NH(CH2)(3)Si(OEt)(3)](6) as gelator. Nanocomposites (G' (1) ), (G' (2) ) and (G' (3) ) exhibited mainly morphological differences while in some cases composition differences when using TEOS as gelator., Some simple metal-containing compounds as (O3SCF3)Ag(PPh3)(HOC5H4N), [CuCl2 center dot NC5H4OH] and [CuCl2 center dot NCCH2C6H4OH]-which are useful models of the most complexes (G (5) ), (G (6) ) and (G (7) ) were also prepared and incorporated in amorphous silica. Their pyrolytic products were compared with those of more complex cyclotriphosphazene analogous. Interestingly, the pyrolysis of the nanocomposite [(O3SCF3)Ag(PPh3)(HOC5H4N)][SiO2] (n) affords the firstly-reported materials containing Ag2O along with SiO2 nanoparticles.},
keywords = {bridged catalyst, copper cyclotriphospahzenes, mesoporous metallic nanoparticles, nanostructures, phosphoric-acid polysilsesquioxanes, precursors, silica, sol-gel sol-gel, synthesis, thermolytic thin-films, transformation, xerogel},
pubstate = {published},
tppubtype = {article}
}

@article{RN1_98,
title = {Adsorption Behavior of Hydrophobically Modified Polyelectrolytes onto Amino- or Methyl-Terminated Surfaces},
author = { X. Briones and M.V. Encinas and D.F.S. Petri and J. Pavez and R.A. Tapia and M. Yazdani-Pedram and M. Urz\'{u}a},
url = {/brokenurl#<Go to ISI>://WOS:000296598300017},
doi = {10.1021/la2025632},
issn = {0743-7463},
year = {2011},
date = {2011-01-01},
journal = {Langmuir},
volume = {27},
number = {22},
pages = {13524-13532},
abstract = {The adsorption of hydrophobically modified polyelectrolytes derived from poly(maleic anhydride-alt-styrene) (P(MA-alt-St)) containing in their side chain aryl-alkyl groups onto amino- or methyl-terminated silicon wafers was investigated. The effect of the spacer group, the chemical nature of the side chain, molecular weight of polyelectrolyte, and ionic strength of solution on the polyelectrolyte adsorbed amount was studied by null ellipsometry. The adsorbed amount of polyelectrolyte increased with increasing ionic strength, in agreement with the screening-enhanced adsorption regime, indicating that hydrophobic interactions with the surface play an important role in the adsorption process. At constant ionic strength, the adsorbed amount was slightly higher for polyelectrolytes with larger alkyl side chain and decreased with the hydrophobicity of aryl group. The adsorption behavior is discussed in terms of the side chain flexibility of the polymer. Characteristics of the adsorbed layer were studied by atomic force microscopy (AFM) and contact angle measurements. AFM images show the presence of aggregates and closed globular structure of polyelectrolyte onto the amino- or methyl-terminated surface, which agrees with a 3D and 2D growth mechanism, respectively. Fluorescence measurements showed that the aggregation of polyelectrolyte containing the hydrophobic naphthyl group occurs already in the solution. However, the aggregation of polyelectrolytes containing the phenyl group in its side chain is not observed in solution but is induced by the amino-terminated surface. This difference can be explained in terms of the higher flexibility of side chain bearing the phenyl group. The polyelectrolyte films showed a high chemical heterogeneity and moderate hydrophobicity.},
keywords = {anhydride), carboxymethyl cellulose, charge complexes, layers, silica, solid-surfaces, solvent, sulfate},
pubstate = {published},
tppubtype = {article}
}