The conformations of narasin–metal complexes in solution determined by NMR spectroscopy
Abstract
The structures in solution of the Na+, K+, Rb+ and Cs+ salts of narasin have been determined by the use of ⋯
O(1)) in the Na+, K+ and Rb+ salts which is much weaker in the Cs+ salt. There is a relatively strong hydrogen bond between OH(4) and O(2) in all four salts and a much weaker hydrogen bond between OH(8) and O(2) seen only in the Na+ salt. The relative tightness of the binding increases as the metal ion size increases.