Molecular organization and solution properties of N-substituted aminomethane-1,1-diphosphonic acids†
Abstract
The crystal structures of N-n-pentylaminomethane-1,1-diphosphonic (1), N-pyrrolidinomethane-1,1-diphosphonic (2), N-(3-carboxy-2-pyridyl)aminomethane-1,1-diphosphonic (3a) and N-(5-methyl-2-pyridyl)aminomethane-1,1-diphosphonic (3c) acids are determined and discussed with respect to their packing patterns and solid state organization. The molecular association and the possible aggregate forms in solution, resulting from the supramolecular features of these materials, are considered. The solution UV and NMR studies are focused on the N-2-pyridylaminomethane-1,1-diphosphonic acids 3a–e in order to establish the influence of the structural changes in passing from 3- to 5- or 6-pyridyl substituted aminomethane-1,1-diphosphonic acids on their general complexation properties.