ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Theoretical binding affinities and spectra of complexes formed by a cyclic β-peptoid with amino acids

Yu Sun, Jinpei Du, Ying Wang, and Shi Wu

Department of Chemistry, Zhejiang University, Hangzhou, 310027, China

E-mail: wushi@zju.edu.cn

Received: 29 May 2009  Revised: 5 January 2010  Accepted: 5 January 2010

Abstract: Binding affinities of a cyclic β-peptoid to amino acids were studied using the density functional theory (DFT) at the B3LYP/6-311G(d,p) level after the basis set superior error (BSSE). The host molecule possesses binding ability to amino acids since the binding energies of the complexes formed are negative. The complexes were stabilized via hydrogen bonds between the host and the guest molecules. Based on the B3LYP/6-31G(d) optimized geometries, electronic spectra of the complexes were calculated using the INDO/CIS method. ¹³C NMR spectra and nucleus-independent chemical shift (NICS) values of the complexes were computed at the B3LYP/6-31G(d) level. Carbon atoms in the carboxyl groups of the complexes are shifted downfield relative to those of the host. Some complexes exhibit aromaticity although the host shows anti-aromaticity. Formation of hydrogen bonds leads to cyclic current formation in these complexes.

Keywords: cyclic β-peptoid - amino acids - binding energy - chemical shift - aromaticity

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-010-0029-3

Chemical Papers 64 (4) 515–522 (2010)