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Arginine interactions with anatase TiO2 (100) surface and the perturbation of 49Ti NMR chemical shifts--a DFT investigation: relevance to Renu-Seeram bio solar cell.

Koch R, Lipton AS, Filipek S, Renugopalakrishnan V - J Mol Model (2010)

Bottom Line: Density functional theoretical calculations have been utilized to investigate the interaction of the amino acid arginine with the (100) surface of anatase and the reproduction of experimentally measured (49)Ti NMR chemical shifts of anatase.Significant binding of arginine through electrostatic interaction and hydrogen bonds of the arginine guanidinium protons to the TiO(2) surface oxygen atoms is observed, allowing attachment of proteins to titania surfaces in the construction of bio-sensitized solar cells.GIAO-B3LYP/6-31G(d) NMR calculation of a three-layer model based on the experimental structure of this TiO(2) modification gives an excellent reproduction of the experimental value (-927 ppm) within +/- 7 ppm, however, the change in relative chemical shifts, EFGs and CSA suggest that the effect of the electrostatic arginine binding might be too small for experimental detection.

View Article: PubMed Central - PubMed

Affiliation: Institute for Pure and Applied Chemistry and Center of Interface Science, University of Oldenburg, Oldenburg, Germany. rainer.koch@uni-oldenburg.de

ABSTRACT
Density functional theoretical calculations have been utilized to investigate the interaction of the amino acid arginine with the (100) surface of anatase and the reproduction of experimentally measured (49)Ti NMR chemical shifts of anatase. Significant binding of arginine through electrostatic interaction and hydrogen bonds of the arginine guanidinium protons to the TiO(2) surface oxygen atoms is observed, allowing attachment of proteins to titania surfaces in the construction of bio-sensitized solar cells. GIAO-B3LYP/6-31G(d) NMR calculation of a three-layer model based on the experimental structure of this TiO(2) modification gives an excellent reproduction of the experimental value (-927 ppm) within +/- 7 ppm, however, the change in relative chemical shifts, EFGs and CSA suggest that the effect of the electrostatic arginine binding might be too small for experimental detection.

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Model of (100) TiO2 anatase surface, top (left) and side (right) views; oxygen atoms in red, titanium atoms in gray
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Fig1: Model of (100) TiO2 anatase surface, top (left) and side (right) views; oxygen atoms in red, titanium atoms in gray

Mentions: TiO2 surfaces have been thoroughly studied, both experimentally and theoretically [29–40]. Also, the adsorption of small molecules on TiO2 surface has been reported in the literature recently [41–52]. Based on previous experience with the calculation of 49Ti NMR chemical shifts [25], we have started to explore a suitable model for the TiO2 (100) surface on which the bR is attached [15]. This surface is one of the two major cleavage planes, together with the (101) surface. It possesses small grooves formed by oxygen atoms on either side of the groove along with both Ti and O atoms at the bottom. Several repeat unit cells are required for reliable and consistent data, since there are relative chemical shifts in the range of several hundred ppm for individual Ti atoms. The model employed herein to represent the (100) surface of anatase consists of 30 TiO2 units, terminated with 12 hydrogen atoms (Fig. 1). It has been taken from the crystal structure of TiO2 anatase [53] and the positions of all surface and added hydrogen atoms are kept fixed during the optimization, only allowing the amino acid to move freely on the surface.Fig. 1


Arginine interactions with anatase TiO2 (100) surface and the perturbation of 49Ti NMR chemical shifts--a DFT investigation: relevance to Renu-Seeram bio solar cell.

Koch R, Lipton AS, Filipek S, Renugopalakrishnan V - J Mol Model (2010)

Model of (100) TiO2 anatase surface, top (left) and side (right) views; oxygen atoms in red, titanium atoms in gray
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3102192&req=5

Fig1: Model of (100) TiO2 anatase surface, top (left) and side (right) views; oxygen atoms in red, titanium atoms in gray
Mentions: TiO2 surfaces have been thoroughly studied, both experimentally and theoretically [29–40]. Also, the adsorption of small molecules on TiO2 surface has been reported in the literature recently [41–52]. Based on previous experience with the calculation of 49Ti NMR chemical shifts [25], we have started to explore a suitable model for the TiO2 (100) surface on which the bR is attached [15]. This surface is one of the two major cleavage planes, together with the (101) surface. It possesses small grooves formed by oxygen atoms on either side of the groove along with both Ti and O atoms at the bottom. Several repeat unit cells are required for reliable and consistent data, since there are relative chemical shifts in the range of several hundred ppm for individual Ti atoms. The model employed herein to represent the (100) surface of anatase consists of 30 TiO2 units, terminated with 12 hydrogen atoms (Fig. 1). It has been taken from the crystal structure of TiO2 anatase [53] and the positions of all surface and added hydrogen atoms are kept fixed during the optimization, only allowing the amino acid to move freely on the surface.Fig. 1

Bottom Line: Density functional theoretical calculations have been utilized to investigate the interaction of the amino acid arginine with the (100) surface of anatase and the reproduction of experimentally measured (49)Ti NMR chemical shifts of anatase.Significant binding of arginine through electrostatic interaction and hydrogen bonds of the arginine guanidinium protons to the TiO(2) surface oxygen atoms is observed, allowing attachment of proteins to titania surfaces in the construction of bio-sensitized solar cells.GIAO-B3LYP/6-31G(d) NMR calculation of a three-layer model based on the experimental structure of this TiO(2) modification gives an excellent reproduction of the experimental value (-927 ppm) within +/- 7 ppm, however, the change in relative chemical shifts, EFGs and CSA suggest that the effect of the electrostatic arginine binding might be too small for experimental detection.

View Article: PubMed Central - PubMed

Affiliation: Institute for Pure and Applied Chemistry and Center of Interface Science, University of Oldenburg, Oldenburg, Germany. rainer.koch@uni-oldenburg.de

ABSTRACT
Density functional theoretical calculations have been utilized to investigate the interaction of the amino acid arginine with the (100) surface of anatase and the reproduction of experimentally measured (49)Ti NMR chemical shifts of anatase. Significant binding of arginine through electrostatic interaction and hydrogen bonds of the arginine guanidinium protons to the TiO(2) surface oxygen atoms is observed, allowing attachment of proteins to titania surfaces in the construction of bio-sensitized solar cells. GIAO-B3LYP/6-31G(d) NMR calculation of a three-layer model based on the experimental structure of this TiO(2) modification gives an excellent reproduction of the experimental value (-927 ppm) within +/- 7 ppm, however, the change in relative chemical shifts, EFGs and CSA suggest that the effect of the electrostatic arginine binding might be too small for experimental detection.

Show MeSH