Ab Initio Study of the Lowest Energy Conformers and IR Spectra of Poly(amidoamine)-G0 Dendrimers

A systematic sequential procedure is implemented to find local minimum conformers corresponding to the lowest generation (G0), −NH2- and −OH-terminated, poly(amidoamine) (PAMAM) dendrimers, and their IR vibrational spectra using ab initio (Hartree−Fock and density functional theory) techniques. It i...

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Bibliographic Details
Published in:The journal of physical chemistry. B 2004-10, Vol.108 (41), p.15982-15991
Main Authors: Tarazona-Vasquez, Francisco, Balbuena, Perla B
Format: Article
Language:English
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Summary:A systematic sequential procedure is implemented to find local minimum conformers corresponding to the lowest generation (G0), −NH2- and −OH-terminated, poly(amidoamine) (PAMAM) dendrimers, and their IR vibrational spectra using ab initio (Hartree−Fock and density functional theory) techniques. It is found that the most stable conformations of PAMAM-G0 dendrimers in the gas phase have all their secondary amide groups in the trans conformation. Interbranch interactions including intramolecular H-bonds play a definite role in providing structural stability. The calculated electronic density spatial distribution reveals the existence of three regions where appropriate environments would attract either an ion or a metal atom:  the core, the amide, and the terminal group (NH2 or OH) sites. A detailed analysis of the IR spectra for the lowest energy conformers of PAMAM-NH2 and PAMAM-OH is thoroughly analyzed and compared with experimental data when available.
ISSN:1520-6106
1520-5207
DOI:10.1021/jp049325i