Issue 31, 2016

Metal ion binding by pyridylethyl-containing polymers: experimental and theoretical study

Abstract

Binding of Cu2+, Ni2+ and Ag+ ions to polyallylamine (PAA), polyethylenimine (PEI), poly(N-2-(2-pyridyl)ethylallylamine) (PEPAA), poly(N-2-(2-pyridyl)ethylethylenimine) (PEPEI), and N-2-(2-pyridyl)ethylchitosan (PEC) has been investigated using batch sorption experiments, spectrophotometric titration, ESR, and XPS to elucidate how the structure of polymer precursors affects the ion binding efficiency of their pyridylethylated derivatives. It has been shown that pyridylethylation increases the sorption capacities of PAA and PEI cross-linked with epichlorohydrin toward Ag+ and Ni2+ ions, but does not improve or decrease that toward Cu2+ ions. PEC was the most efficient material for Ag+ ion sorption with the sorption capacity of 1.21 mmol g−1. The highest sorption capacity for Ni2+ (0.62 mmol g−1) was found for PEPEI. According to density functional theory (DFT) calculations, lower Cu2+ binding efficiency to PEPEI results from the “looser” structure of this complex in comparison with unmodified PEI. DFT calculations have also suggested that the Cu2+ ion is four-coordinated in the complexes with PEPAA and PAA and five-coordinated in all other complexes, which have the structures of distorted square pyramids with Cu–N bond lengths varying significantly depending on the ligand nature. The results of the theoretical investigations of the Cu2+ complex structures were supported by the ESR data, which revealed the decrease of A and the increase of g values with increasing deviation from the square planar geometry of complexes in the ligands in the order PEI < PEPEI < PEPAA.

Graphical abstract: Metal ion binding by pyridylethyl-containing polymers: experimental and theoretical study

Supplementary files

Article information

Article type
Paper
Submitted
14 Apr 2016
Accepted
04 Jul 2016
First published
05 Jul 2016

Dalton Trans., 2016,45, 12372-12383

Metal ion binding by pyridylethyl-containing polymers: experimental and theoretical study

S. Bratskaya, A. Voit, Y. Privar, A. Ziatdinov, A. Ustinov, D. Marinin and A. Pestov, Dalton Trans., 2016, 45, 12372 DOI: 10.1039/C6DT01435F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements