Adsorption of 2-Mercaptopyrimidine on Silver Nanoparticles in Water

Autor:	G. N. R. Tripathi and, Melisa Clements
Rok vydání:	2003
Předmět:	chemistry.chemical_classification Aqueous solution Inorganic chemistry Protonation Ring (chemistry) Tautomer Silver nanoparticle Surfaces Coatings and Films Adsorption chemistry Materials Chemistry Thiol Molecule Physical chemistry Physical and Theoretical Chemistry
Zdroj:	The Journal of Physical Chemistry B. 107:11125-11132
ISSN:	1520-5207 1520-6106
DOI:	10.1021/jp030546i
Popis:	Adsorption of 2-mercaptopyrimidine (2-MP), a prototype of biologically important N-heterocyclic aromatic thiols, has been examined on 100−120 nm silver particles in aqueous solution. Density functional calculations (UBPW91/6-31+G**) on various thione and thiol tautomers of the molecule have been performed to augment experimental data on reference vibrational frequencies. Criteria for determining the structural form of the molecule on the metal−water interface and its binding site and strength have been developed. The frequencies of the ring stretching Wilson modes 8a and 8b and their separation (Δv8a-8b) are good indicators of the protonation state of the molecule. The experimental Δv8a-8b for the Ag-bound 2-MP (20(±2) cm-1 in the pH range 4−11) identifies the structural form with the neutral thiol (C4H3N2S−), rather than thiolate (C4H3N2S-−). The molecule bonds with the Ag surface at its S site. A noticeable change in the SERS intensity pattern occurs around pH 6.5 due to the change in the surface enviro...
Databáze:	OpenAIRE
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