Interaction mechanisms between poly(amido‐amine) and nano‐silicon dioxide

To gain insight into the attachment of ?Si⁺ (SC) and ?SiO^? (SOA) ions (regarded as guests) to the lowest generation, ? NH₂‐terminated poly(amidoamine) (PAMAM) dendrimers (regarded as host) in the gas phase, density functional theory is used to investigate the structures and energetics of the complexes with B3LYP/6‐31+G (d) and HF/6‐31G basis sets. The initial parameters are obtained through the initial optimizations at the HF level using the most basic STO‐3G basis set. Various initial configurations of the ions bound to PAMAM are tested, and four stable conformers are found, i.e., types A to D. Types 1A and 2C are the most stable due to the chemical bond formations of Si? N° and Si? O, respectively. For type B, SC coordination to amide O sites occurs via electrostatic induction. For type D, SOA coordination to amide hydrogen and amine hydrogen sites occurs via hydrogen bond interaction. Spatial hindrance, electrostatic induction force, and hydrogen‐bond interaction play important roles in the complexation process. © 2013 Wiley Periodicals, Inc. This article was published online on 5 July 2012. An error was subsequently identified. This notice is included in the online and print version to indicate that both have been corrected on 3 August 2012.