Selective complexation of divalent cations by a cyclic α,β-peptoid hexamer: a spectroscopic and computational study.
We describe the qualitative and quantitative analysis of the complexation properties towards cations of a cyclic peptoid hexamer composed of alternating α- and β-peptoid monomers, which bear exclusively chiral (S)-phenylethyl side chains (spe) that have no noticeable chelating properties. The binding of a series of monovalent and divalent cations was assessed by1H NMR, circular dichroism, fluorescence and molecular modelling. In contrast to previous studies on cations binding by 18-membered α-cyclopeptoid hexamers, the 21-membered cyclopeptoid cP1 did not complex monovalent cations (Na+, K+, Ag+) but showed selectivity for divalent cations (Ca2+, Ba2+, Sr2+and Mg2+). Hexacoordinated C-3 symmetrical complexes were demonstrated for divalent cations with ionic radii around 1 Å (Ca2+and Ba2+), while 5-coordination is preferred for divalent cations with larger (Ba2+) or smaller ionic radii (Mg2+).
Medway School of Pharmacy, Universities of Kent and Greenwich at Medway, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK. emiliana.de.santis@npl.co.uk.
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De Santis
Medway School of Pharmacy, Universities of Kent and Greenwich at Medway, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK. emiliana.de.santis@npl.co.uk.
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Edwards
School of Science, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK.
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Alexander
Functional Materials Group, School of Physical Sciences, University of Kent, Canterbury, CN2 7NZ, UK. S.J.Holder@kent.ac.uk.
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Holder
Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France. claude.taillefumier@univ-bpclermont.fr and CNRS, UMR 6296, ICCF, F-63178 Aubière Cedex, France.
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Biesse-Martin
School of Science, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK.
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Nielsen
Division of Pharmacy and Pharmaceutical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DE, UK.
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Mistry
Division of Pharmacy and Pharmaceutical Sciences, University of Huddersfield, Queensgate, Huddersfield, HD1 3DE, UK.
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Waters
Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK.
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Siligardi
Diamond Light Source Ltd, Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK.
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Hussain
Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France. claude.taillefumier@univ-bpclermont.fr and CNRS, UMR 6296, ICCF, F-63178 Aubière Cedex, France.
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Faure
Université Clermont Auvergne, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand, France. claude.taillefumier@univ-bpclermont.fr and CNRS, UMR 6296, ICCF, F-63178 Aubière Cedex, France.
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Taillefumier
D002413:Cations, Divalent / Q000737:chemistry; D002942:Circular Dichroism; D005453:Fluorescence; D008958:Models, Molecular; D015394:Molecular Structure; D034444:Peptoids / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy
D002413:Cations, Divalent; D034444:Peptoids