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| 2. |
- Andersson, Patrik, et al.
(författare)
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Chemical characterization of brominated flame retardants and identification
- 2006
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Ingår i: Environmental Toxicology and Chemistry. - 0730-7268. ; 25:5, s. 1275-82
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Tidskriftsartikel (refereegranskat)abstract
- Three training sets were selected, each consisting of 10 structurally diverse compounds representative of brominated flame retardants (BFRs) that are either in use or have been used. Just three compounds account for nearly all the total production volume of BFRs. In the present study, however, the physicochemical characteristics of a far more structurally diverse set of 65 BFRs was explored using 15 molecular descriptors (including log P, constitutional counts, and semiempirical quantum mechanical parameters) and principal component analysis (PCA). The PCA generated an overview of the structural variation among BFRs, and certain compounds with unique physicochemical properties and specific clusters of compounds with distinct properties were identified. The training-set compounds were selected by applying the condensed information obtained from the PCA and statistical experimental design. The three training sets, which were designated as optimal, practical, and alternative, were selected either to maximize the structural variation (optimal) or to combine structural variation with practical advantages, such as ease of experimental handling and commercial availability (practical and alternative). Inclusion of the suggested compounds in assessments of the persistence, bioaccumulation, and toxicity properties of BFRs and related programs should help to increase our understanding of the effects and environmental fate of these compounds.
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| 3. |
- Lind, Per, et al.
(författare)
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A QSPR study on optical limiting of organic compounds
- 2004
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Ingår i: Chemical Physics Letters. - Amsterdam : North-Holland Publishing Co. - 0009-2614 .- 1873-4448. ; 387:4-6, s. 238-242
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Tidskriftsartikel (refereegranskat)abstract
- The optical limiting performance of 23 structurally different organic compounds has been measured at the wavelength of 532 nm. Molecular orbital ab initio calculations were performed to generate molecular electronic variables that were applied in a quantitative structure–property relationship (QSPR) study. A model that predicts the optical limiting response was constructed by using a partial least square (PLS) analysis. Six variables that play a major role for the optical limiting ability of organic materials were identified.
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| 4. |
- Oberg, K., et al.
(författare)
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Comparison of monolayer films of stearic acid and methyl stearate on an Al2O3 surface
- 2001
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090. ; 397:1-2, s. 102-8
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Tidskriftsartikel (refereegranskat)abstract
- Both stearic acid and methyl stearate chemisorbs onto an oxide surface of aluminum with an asymmetric coordination of the carboxylate group as concluded from infrared (IR) spectroscopy data. Similarities in the IR spectra of the films from the two compounds suggest that the ester is bonded in the same way as the acid, and that the ester therefore undergoes hydrolysis during the surface reaction. X-Ray photoelectron spectroscopy (XPS) and IR data are interpreted in terms of self-assembled monolayer formation and a more dense film from the carboxylic acid in comparison with that from the ester. (C) 2001 Elsevier Science B.V. All rights reserved.
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| 5. |
- Öberg, Kjell, et al.
(författare)
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A method for screening of coverage and film thickness of monolayers by projection of molecular electron density surface onto a substrate plane
- 2001
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Ingår i: Materials Letters. ; 49:3-4, s. 147-153
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Tidskriftsartikel (refereegranskat)abstract
- Self-assembled monolayer films of a copper tetraazaphthalocyanine have been prepared on quartz and silicon at 120°C in DMF solution and at 250°C in bromonaphthalene solution. A procedure is presented for obtaining film thickness for a sufficiently dense monolayer by fitting the 2D image of the 3D electron density surface of the chromophore in the film to a surface-coverage measure derived from absorption spectroscopy. The film thickness obtained by the electron density projection method is compared to that from ellipsometry. The projection method is expected to be useful for film-screening purposes and can also yield an average angle between the surface and chromophore normals.
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| 6. |
- Öberg, Kjell, et al.
(författare)
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Comparison of monolayer films of stearic acid and methyl stearate on an Al2O3 surface
- 2001
-
Ingår i: Thin Solid Films. ; 397:1-2, s. 102-8
-
Tidskriftsartikel (refereegranskat)abstract
- Both stearic acid and methyl stearate chemisorbs onto an oxide surface of aluminum with an asymmetric coordination of the carboxylate group as concluded from infrared (IR) spectroscopy data. Similarities in the IR spectra of the films from the two compounds suggest that the ester is bonded in the same way as the acid, and that the ester therefore undergoes hydrolysis during the surface reaction. X-Ray photoelectron spectroscopy (XPS) and IR data are interpreted in terms of self-assembled monolayer formation and a more dense film from the carboxylic acid in comparison with that from the ester.
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| 7. |
- Öberg, Kjell, et al.
(författare)
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Prediction of nonlinear optical responses of organic compounds
- 2001
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Ingår i: Journal of Chemical Information and Modeling. - : American Chemical Society (ACS). - 0095-2338. ; 41:3, s. 811-4
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Tidskriftsartikel (refereegranskat)abstract
- The nonlinear optical quantities, second and third harmonics ( and ), were predicted using a quantitative structure-property relationship (QSPR) approach. Molecular orbital ab initio calculations were applied to generate easily accessible variables to be used in the partial least-squares analysis. Simplified equations are presented that could be used to predict the experimental and responses, prior to further investigations of potentially interesting molecules for use in optical materials.
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| 8. |
- Öberg, Kjell, et al.
(författare)
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Spectroscopic Characterization of the Bonding, Orientation, and Coverage of Copper Tetraazaphthalocyanine Monolayer Films on SiO2 Surfaces
- 2000
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Ingår i: The Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 104:45, s. 10627-34
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Tidskriftsartikel (refereegranskat)abstract
- Self-assembled monolayer films of a metallotetraazaphthalocyanine were prepared using two different reaction conditions. The films were characterized by ellipsometry, AFM, electronic absorption spectroscopy, semiempirical MO calculations, core-level XPS, and projection of a calculated structure of the chromophore onto a surface to obtain its silhouette area for comparison with surface concentration from absorption spectroscopy. A denser packing of the chromophores is found in the SAM film prepared with bromonaphthalene at 250 C as compared with the film from the more polar solvent DMF at 120 C. Data is consistent with an almost vertical orientation of the chromophores in the former film. A different number of bonds connecting the chromophore with the coupling molecule is suggested as an explanation to differences in the absorption bands for the two films.
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