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de Donato A, Ghejan BA, Bakker JM, Bernhardt TM, Bromley ST, Lang SM. Gas-Phase Production of Hydroxylated Silicon Oxide Cluster Cations: Structure, Infrared Spectroscopy, and Astronomical Relevance. ACS EARTH & SPACE CHEMISTRY 2024; 8:1154-1164. [PMID: 38919856 PMCID: PMC11194846 DOI: 10.1021/acsearthspacechem.3c00346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 04/01/2024] [Accepted: 04/02/2024] [Indexed: 06/27/2024]
Abstract
The interaction of free cationic silicon oxide clusters, Si x O y + (x = 2-5, y ≥ x), with dilute water vapor, was investigated in a flow tube reactor. Product mass distributions indicate cluster size-dependent dissociative water adsorption. To probe the structure and vibrational spectra of the resulting Si x O y H2 + (x = 2-4) clusters, we employed infrared multiple photon dissociation spectroscopy and density functional theory calculations. The planar rhombic cluster core of the disilicon oxides (x = 2) appears to be retained upon dissociative adsorption of one H2O unit, whereas a significant structural transformation of the tri- and tetra-silicon oxides (x = 3 and 4) is induced, resulting in an increased coordination of the Si atoms and more 3D cluster structures. In an astronomical context, we discuss the potential relevance of Si x O y H z + clusters as seeds for dust nucleation and catalysts for carbon-based chemistry in diffuse or translucent interstellar clouds, where all the necessary conditions for producing these species are found. In the produced clusters, the frequency of the isolated silanol Si-OH stretching vibrational mode is considerably blue-shifted compared to that in hydroxylated bulk silica and small inorganic compounds. This mode has a characteristic frequency range between 1200 cm-1 (8.3 μm) and 1090 cm-1 (9.2 μm) and is associated with the anomalously small Si-OH bond lengths in these ionised species. In infrared observations such high frequency Si-O stretching modes are usually associated with a pure bulk silica component of silicate cosmic dust. The presence of Si x O y H2 + clusters in low silica astrophysical environments could thus potentially be detected via their signature Si-O band using the James Webb space telescope.
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Affiliation(s)
- Andreu
A. de Donato
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacio-nal (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, Barcelona 08028, Spain
| | | | - Joost M. Bakker
- Radboud
University, Institute of Molecules and Materials, FELIX Laboratory, Nijmegen 6525 ED, The Netherlands
| | | | - Stefan T. Bromley
- Departament
de Ciència de Materials i Química Física &
Institut de Química Teòrica i Computacio-nal (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, Barcelona 08028, Spain
- Institució
Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, Bar-celona E-08010, Spain
| | - Sandra M. Lang
- Institute
of Surface Chemistry and Catalysis, University
of Ulm, Ulm 89069, Germany
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Berniak T, Łątka P, Drozdek M, Rokicińska A, Jaworski A, Leyva-Pérez A, Kuśtrowski P. Covalent bonding of N-hydroxyphthalimide on mesoporous silica for catalytic aerobic oxidation of p-xylene at atmospheric pressure. Chempluschem 2024; 89:e202300631. [PMID: 38375758 DOI: 10.1002/cplu.202300631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 01/31/2024] [Accepted: 02/15/2024] [Indexed: 02/21/2024]
Abstract
The surface of SBA-15 mesoporous silica was modified by N-hydroxyphthalimide (NHPI) moieties acting as immobilized active species for aerobic oxidation of alkylaromatic hydrocarbons. The incorporation was carried out by four original approaches: the grafting-from and grafting-onto techniques, using the presence of surface silanols enabling the formation of particularly stable O-Si-C bonds between the silica support and the organic modifier. The strategies involving the Heck coupling led to the formation of NHPI groups separated from the SiO2 surface by a vinyl linker, while one of the developed modification paths based on the grafting of an appropriate organosilane coupling agent resulted in the active phase devoid of this structural element. The successful course of the synthesis was verified by FTIR and 1H NMR measurements. Furthermore, the formed materials were examined in terms of their chemical composition (elemental analysis, thermal analysis), structure of surface groups (13C NMR, XPS), porosity (low-temperature N2 adsorption), and tested as catalysts in the aerobic oxidation of p-xylene at atmospheric pressure. The highest conversion and selectivity to p-toluic acid were achieved using the catalyst with enhanced availability of non-hydrolyzed NHPI groups in the pore system. The catalytic stability of the material was additionally confirmed in several subsequent reaction cycles.
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Affiliation(s)
- Tomasz Berniak
- Department of Chemical Technology, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Piotr Łątka
- Department of Chemical Technology, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Marek Drozdek
- Department of Chemical Technology, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Anna Rokicińska
- Department of Chemical Technology, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Aleksander Jaworski
- Department of Materials and Environmental Chemistry, Stockholm University, Stockholm, SE-106 91, Sweden
| | - Antonio Leyva-Pérez
- Instituto de Tecnología Química (UPV - CSIC), Universitat Politècnica de València-Consejo Superior de Investigaciones Científicas, Avda. de los Naranjos s/n, Valencia, 46022, Spain
| | - Piotr Kuśtrowski
- Department of Chemical Technology, Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
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Wytrych P, Utko J, Kłak J, Ptak M, Stefanski M, Lis T, Ejfler J, John Ł. Synthesis, Crystal Structures, and Spectroscopic Properties of Novel Gadolinium and Erbium Triphenylsiloxide Coordination Entities. MOLECULES (BASEL, SWITZERLAND) 2021; 27:molecules27010147. [PMID: 35011379 PMCID: PMC8746333 DOI: 10.3390/molecules27010147] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/20/2021] [Accepted: 12/23/2021] [Indexed: 11/16/2022]
Abstract
In alkali metal and lanthanide coordination chemistry, triphenylsiloxides seem to be unduly underappreciated ligands. This is as surprising as that such substituents play a crucial role, among others, in stabilizing rare oxidation states of lanthanide ions, taking a part of intramolecular and molecular interactions stabilizing metal-oxygen cores and many others. This paper reports the synthesis and characterization of new lithium [Li4(OSiPh3)4(THF)2] (1), and sodium [Na4(OSiPh3)4] (2) species, which were later used in obtaining novel gadolinium [Gd(OSiPh3)3(THF)3]·THF (3), and erbium [Er(OSiPh3)3(THF)3]·THF (4) configuration, it can result in res were determined for all 1-4 compounds, and in addition, IR, Raman, absorption spectroscopy studies were conducted for 3 and 4 lanthanide compounds. Furthermore, direct current (dc) variable-temperature magnetic susceptibility measurements on polycrystalline samples of 3 and 4 were carried out in the temperature range 1.8-300 K. The 3 shows behavior characteristics for the paramagnetism of the Gd3+ ion. In contrast, the magnetic properties of 4 are dominated by the crystal field effect on the Er3+ ion, masking the magnetic interaction between magnetic centers of neighboring molecules.
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Affiliation(s)
- Patrycja Wytrych
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Józef Utko
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Julia Kłak
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Maciej Ptak
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 2 Okólna, 50-422 Wrocław, Poland; (M.P.); (M.S.)
| | - Mariusz Stefanski
- Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 2 Okólna, 50-422 Wrocław, Poland; (M.P.); (M.S.)
| | - Tadeusz Lis
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Jolanta Ejfler
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
| | - Łukasz John
- Faculty of Chemistry, University of Wrocław, 14 F. Joliot-Curie, 50-383 Wrocław, Poland; (P.W.); (J.U.); (J.K.); (T.L.); (J.E.)
- Correspondence:
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Smirnov KS. Structure and sum-frequency generation spectra of water on neutral hydroxylated silica surfaces. Phys Chem Chem Phys 2021; 23:6929-6949. [PMID: 33729227 DOI: 10.1039/d0cp06465c] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Structural organization and vibrational sum-frequency generation (VSFG) spectra of water on crystalline and amorphous neutral silica surfaces were investigated by classical molecular dynamics simulations. The liquid phase represented with neat water and 1 M NaCl solution was analysed in terms of bonded interfacial layer (BIL), diffuse layer (DL) and bulk region. The simulations show that the structure of BIL depends on the surface morphology and density of surface OH groups. The water-silanol H-bond network and BIL structure are mainly insensitive to the presence of ions in the liquid phase. Molecules in DL of SiO2/neat water interfaces preferentially orient their OH bonds towards the surfaces. This effect is directly related to an effective negative charge of formally neutral surfaces. Ions of the electrolyte solution affect the intermolecular structure in DL by screening the surface electric field and by the chaotropic effect. Calculated phase-sensitive VSFG (Im[χ(2)]) spectrum of BIL features low-frequency negative and high-frequency positive bands. Characteristics of the positive band reflect the strength of water-surface interactions and surface crystallinity, while the position and shape of the negative band are common to all interfaces. The Im[χ(2)] spectrum of DL is dominated by a contribution from the third-order χ(3) susceptibility with the sign of the contribution directly related to the sign of electrostatic potential in the interfacial region. The DL spectrum is strongly affected by the presence of solvated ions. The computed intensity and Im[χ(2)] spectra of the amorphous silica/NaCl solution interface are in a good agreement with the conventional and phase-sensitive experimental VSFG spectra of fused SiO2/water system at low pH, in contrast to the spectra of the amorphous silica/neat water interface. Origins of the discrepancy are discussed.
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Affiliation(s)
- Konstantin S Smirnov
- Univ. Lille, CNRS, UMR 8516 - LASIRe - Laboratoire Avancé de Spectroscopie pour les Interactions la Réactivité et l'Environnement, F-59000 Lille, France.
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Accolla M, Santoro G, Merino P, Martínez L, Tajuelo-Castilla G, Vázquez L, Sobrado JM, Agúndez M, Jiménez-Redondo M, Herrero VJ, Tanarro I, Cernicharo J, Martín-Gago JÁ. Silicon and Hydrogen Chemistry under Laboratory Conditions Mimicking the Atmosphere of Evolved Stars. THE ASTROPHYSICAL JOURNAL 2021; 906:44. [PMID: 33594293 PMCID: PMC7116752 DOI: 10.3847/1538-4357/abc703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Silicon is present in interstellar dust grains, meteorites and asteroids, and to date thirteen silicon-bearing molecules have been detected in the gas-phase towards late-type stars or molecular clouds, including silane and silane derivatives. In this work, we have experimentally studied the interaction between atomic silicon and hydrogen under physical conditions mimicking those at the atmosphere of evolved stars. We have found that the chemistry of Si, H and H2 efficiently produces silane (SiH4), disilane (Si2H6) and amorphous hydrogenated silicon (a-Si:H) grains. Silane has been definitely detected towards the carbon-rich star IRC+10216, while disilane has not been detected in space yet. Thus, based on our results, we propose that gas-phase reactions of atomic Si with H and H2 are a plausible source of silane in C-rich AGBs, although its contribution to the total SiH4 abundance may be low in comparison with the suggested formation route by catalytic reactions on the surface of dust grains. In addition, the produced a-Si:H dust analogs decompose into SiH4 and Si2H6 at temperatures above 500 K, suggesting an additional mechanism of formation of these species in envelopes around evolved stars. We have also found that the exposure of these dust analogs to water vapor leads to the incorporation of oxygen into Si-O-Si and Si-OH groups at the expense of SiH moieties, which implies that, if this type of grains are present in the interstellar medium, they will be probably processed into silicates through the interaction with water ices covering the surface of dust grains.
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Affiliation(s)
- Mario Accolla
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Gonzalo Santoro
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Pablo Merino
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics. c/Serrano 123, 28006 Madrid, Spain
| | - Lidia Martínez
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Guillermo Tajuelo-Castilla
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Luis Vázquez
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
| | - Jesús M. Sobrado
- Centro de Astrobiología (CAB. INTA-CSIC). Crta- de Torrejón a Ajalvir km4, 28850, Torrejón de Ardoz, Madrid, Spain
| | - Marcelino Agúndez
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics. c/Serrano 123, 28006 Madrid, Spain
| | - Miguel Jiménez-Redondo
- Instituto de Estructura de la Materia (IEM.CSIC). Molecular Physics Department. c/Serrano 123, 28006 Madrid, Spain
| | - Víctor J. Herrero
- Instituto de Estructura de la Materia (IEM.CSIC). Molecular Physics Department. c/Serrano 123, 28006 Madrid, Spain
| | - Isabel Tanarro
- Instituto de Estructura de la Materia (IEM.CSIC). Molecular Physics Department. c/Serrano 123, 28006 Madrid, Spain
| | - José Cernicharo
- Instituto de Física Fundamental (IFF. CSIC). Group of Molecular Astrophysics. c/Serrano 123, 28006 Madrid, Spain
| | - José Ángel Martín-Gago
- Instituto de Ciencia de Materiales de Madrid (ICMM. CSIC). Materials Science Factory. Structure of Nanoscopic Systems Group. c/Sor Juana Inés de la Cruz 3, 28049 Cantoblanco, Madrid, Spain
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Smirnov KS. A molecular dynamics study of the interaction of water with the external surface of silicalite-1. Phys Chem Chem Phys 2017; 19:2950-2960. [DOI: 10.1039/c6cp06770k] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The modeling study of the interaction of water with the external surface of silicalite-1 reveals retention of H2O molecules at the interface because of the formation of a structured water layer.
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Affiliation(s)
- Konstantin S. Smirnov
- Laboratoire de Spectrochimie Infrarouge et Raman
- UMR 8516 CNRS – Université de Lille – Sciences et Technologies
- France
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Lagström T, Gmür TA, Quaroni L, Goel A, Brown MA. Surface vibrational structure of colloidal silica and its direct correlation with surface charge density. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:3621-6. [PMID: 25761506 DOI: 10.1021/acs.langmuir.5b00418] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We show that attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy can be used to determine the surface charge density (SCD) of colloidal silica nanoparticles (NPs) in aqueous solution. We identify the Si-O stretch vibrations of neutral surface bound silanol, ≡Si-OH, and of the deprotonated group, ≡Si-O(-). The position of the Si-(OH) stretch vibration is shown to directly correlate with the NPs SCD as determined by traditional potentiometric titrations, shifting to lower wavenumber (cm(-1)) with increasing density of ≡Si-O(-). The origin of this shift is discussed in terms of inductive effects that reduce the ionic character of the Si-(OH) bond after delocalization of the negative charge left on a terminal ≡Si-O(-) group across the atoms within ∼1 nm of the charged site. Using this new methodology, we quantitatively determine the SCD of 9, 14, and 25 nm diameter colloidal silica in varying concentrations of NaCl electrolyte at different bulk pH. This novel spectroscopic approach to investigate SCDs provides several opportunities for in situ coupling, for example, in microfluidic channels or with liquid microjets, and requires only very little sample—all potential advantages over a traditional potentiometric titration.
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Affiliation(s)
| | | | - Luca Quaroni
- §Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
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Han HC, Tseng CA, Du CY, Ganguly A, Chong CW, Wang SB, Lin CF, Chang SH, Su CC, Lee JH, Chen KH, Chen LC. Enhancing efficiency with fluorinated interlayers in small molecule organic solar cells. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm34091g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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9
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Rother D, Sen T, East D, Bruce IJ. Silicon, silica and its surface patterning/activation with alkoxy- and amino-silanes for nanomedical applications. Nanomedicine (Lond) 2011; 6:281-300. [DOI: 10.2217/nnm.10.159] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Silica and silicates are widely used in nanomedicine with applications as diverse as medical device coatings to replacement materials in tissue engineering. Although much is known about silica and its synthesis, relatively few biomedical scientists fully appreciate the link that exists between its formulation and its resultant structure and function. This article attempts to provide insight into relevant issues in that context, as well as highlighting their importance in the material’s eventual surface patterning/activation with alkoxy- and organo-silanes. The use of aminosilanes in that context is discussed at some length to permit an understanding of the specific variables that are important in the reproducible and robust aminoactivation of surfaces using such molecules. Recent investigative work is cited to underline the fact that although aminosilanization is a historically accepted mechanism for surface activation, there is still much to be explained about how and why the process works in the way it does. In the last section of this article, there is a detailed discussion of two classical approaches for the use of aminosilanized materials in the covalent immobilization of bioligands, amino-aldehyde and amino-carboxyl coupling. In the former case, the use of the homobifunctional coupler glutaraldehyde is explored, and in the latter, carbodiimides. Although these chemistries have long been employed in bioconjugations, it is apparent that there are still variables to be explored in the processes (as witnessed by continuing investigations into the chemistries concerned). Aspects regarding optimization, standardization and reproducibility of the fabrication of amino functionalized surfaces are discussed in detail and illustrated with practical examples to aid the reader in their own studies, in terms of considerations to be taken into account when producing such materials. Finally, the article attempts to remind readers that although the chemistry and materials involved are ‘old hat’, there is still much to be learnt about the methods involved. The article also reminds readers that although many highly specific and costly conjugation chemistries now exist for bioligands, there still remains a place for these relatively simple and cost-effective approaches in bioligand conjugate fabrication.
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Affiliation(s)
- Dag Rother
- Nanobiotechnology Research Group, School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK
- Bundesanstalt für Arbeitsschutz und Arbeitsmedizin, Freidrich-Henkel-Weg 1-25 D-44149 Dortmund, Germany
| | - Tapas Sen
- Nanobiotechnology Research Group, School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK
- Centre for Materials Science, School of Forensic & Investigative Sciences, University of Central Lancashire, Preston, PR1 2HE, UK
| | - Daniel East
- Nanobiotechnology Research Group, School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK
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Ignatyev I, Montejo M, Ortega PGR, González JJL. Effect of substituents and hydrogen bonding on barrier heights in dehydration reactions of carbon and silicon geminal diols. Phys Chem Chem Phys 2011; 13:18507-15. [DOI: 10.1039/c1cp21580a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Thompho S, Chanajaree R, Remsungnen T, Hannongbua S, Bopp PA, Fritzsche S. The Permeation of Methane Molecules through Silicalite-1 Surfaces. J Phys Chem A 2009; 113:2004-14. [DOI: 10.1021/jp808588n] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Somphob Thompho
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Rungroj Chanajaree
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Tawun Remsungnen
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Supot Hannongbua
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Philippe A. Bopp
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
| | - Siegfried Fritzsche
- Institut für Theoretische Physik, Universität Leipzig, Vor dem Hospitaltore 1, D-04103 Leipzig, Germany, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand, Department of Mathematics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand, and Department of Chemistry, Université Bordeaux 1, Building A12, 351 Cours de la Libération, F-33405 Talence CEDEX, France
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12
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Liu WT, Shen YR. Surface vibrational modes of alpha-quartz(0001) probed by sum-frequency spectroscopy. PHYSICAL REVIEW LETTERS 2008; 101:016101. [PMID: 18764125 DOI: 10.1103/physrevlett.101.016101] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Indexed: 05/26/2023]
Abstract
Infrared-visible sum-frequency spectroscopy was used to probe surface vibrations of alpha-quartz(0001) under ambient conditions. Two modes at 880 and 980 cm(-1) were observed and identified as arising from Si-O-Si and Si-OH structures of the surface. Heat treatment and hydroxylation could convert Si-OH to Si-O-Si and vice versa. The technique is generally applicable to studies of surface phonons of other oxides, semiconductors, and insulators.
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Affiliation(s)
- Wei-Tao Liu
- Physics Department, University of California at Berkeley, Berkeley, California 94720, USA
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13
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Montejo M, Ureña FP, Márquez F, López González JJ. Triethylsilanol: Molecular Conformations and Role of the Hydrogen-Bonding Oligomerization in Its Vibrational Spectra. J Phys Chem A 2008; 112:1545-51. [DOI: 10.1021/jp710237k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Manuel Montejo
- Physical and Analytical Chemistry Department, University of Jaén, Campus Las Lagunillas, E-23071 Jaén, Spain
| | - Francisco Partal Ureña
- Physical and Analytical Chemistry Department, University of Jaén, Campus Las Lagunillas, E-23071 Jaén, Spain
| | - Fernando Márquez
- Physical and Analytical Chemistry Department, University of Jaén, Campus Las Lagunillas, E-23071 Jaén, Spain
| | - Juan Jesús López González
- Physical and Analytical Chemistry Department, University of Jaén, Campus Las Lagunillas, E-23071 Jaén, Spain
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Dover MR, Evans CJ. Computational study on the structures of the [H, Si, N, C, O] isomers: possible species of interstellar interest. J Phys Chem A 2007; 111:13148-56. [PMID: 18004831 DOI: 10.1021/jp076289p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ab initio methods have been used to study the lowest lying [H, Si, N, C, O] isomers, which are of astrochemical interest. Over 20 [H, Si, N, C, O] isomers in the 1A' electronic state have been investigated at the MP2/aug-cc-pVTZ level of theory. Of these, the seven lowest isomers have been further investigated using different levels of theory, including B3LYP and QCISD(T). It has been found that the relative energies of the isomers in their ground electronic state (1A') are very dependent on the level of theory used with either the cis-HOSiCN or cis-HOSiNC isomers being the lowest in energy. Overall, the four lowest isomers are within 6 kcal/mol of each other, and a further three isomers are less than 15 kcal/mol higher in energy than the lowest lying isomer, including HSiNCO, which has recently been detected spectroscopically. Natural bond analysis has been carried out on the ground electronic states of the seven lowest lying isomers to examine their electronic structure. The enthalpies of formation of the seven lowest isomers have also been evaluated using the G3MP2 and G3B3 multilevel methods and show that the isomers are relatively thermodynamically stable. The structures and energies of lowest lying 1A'' and 3A'' electronic states of these isomers have also been investigated and show that for most of the isomers the optimized structures in these excited electronic states correspond to a transition state structure.
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Affiliation(s)
- Matthew R Dover
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom
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Parida SK, Dash S, Patel S, Mishra BK. Adsorption of organic molecules on silica surface. Adv Colloid Interface Sci 2006; 121:77-110. [PMID: 16879799 DOI: 10.1016/j.cis.2006.05.028] [Citation(s) in RCA: 347] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2005] [Revised: 05/17/2006] [Accepted: 05/17/2006] [Indexed: 11/29/2022]
Abstract
The adsorption behaviour of various organic adsorbates on silica surface is reviewed. Most of the structural information on silica is obtained from IR spectral data and from the characteristics of water present at the silica surface. Silica surface is generally embedded with hydroxy groups and ethereal linkages, and hence considered to have a negative charged surface prone to adsorption of electron deficient species. Adsorption isotherms of the adsorbates delineate the nature of binding of the adsorbate with silica. Aromatic compounds are found to involve the pi-cloud in hydrogen bonding with silanol OH group during adsorption. Cationic and nonionic surfactants adsorb on silica surface involving hydrogen bonding. Sometimes, a polar part of the surfactants also contributes to the adsorption process. Styryl pyridinium dyes are found to anchor on silica surface in flat-on position. On modification of the silica by treating with alkali, the adsorption behaviour of cationic surfactant or polyethylene glycol changes due to change in the characteristics of silica or modified silica surface. In case of PEG-modified silica, adsolubilization of the adsorbate is observed. By using a modified adsorption equation, hemimicellization is proposed for these dyes. Adsorptions of some natural macromolecules like proteins and nucleic acids are investigated to study the hydrophobic and hydrophilic binding sites of silica. Artificial macromolecules like synthetic polymers are found to be adsorbed on silica surface due to the interaction of the multifunctional groups of the polymers with silanols. Preferential adsorption of polar adsorbates is observed in case of adsorbate mixtures. When surfactant mixtures are considered to study competitive adsorption on silica surface, critical micelle concentration of individual surfactant also contributes to the adsorption isotherm. The structural study of adsorbed surface and the thermodynamics of adsorption are given some importance in this review.
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Affiliation(s)
- Sudam K Parida
- Centre of Studies in Surface Science and Technology, Department of Chemistry, Jyoti Vihar, 768 019, Orissa, India
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