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 SiN degrees and SiO, 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. (c) 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.