Hydrogen Bonding in α-Aminophosphonic Acids

Abstract

The molecular and crystal structures of two α-aminophosphonic acids with small substituents at the α-carbon atom—(1-aminoethyl)phosphonic acid 1 and (1-amino-2,2-dimethylpropyl)phosphonic acid monohydrate 4—were determined by single-crystal X-ray diffraction studies. The crystal structures provide important information on the hydrogen bonding properties of α-aminophosphonic acids. In the crystal, the molecules are linked together by strong O‒H···O hydrogen bonds, forming chains which are contorted to helix-like structures, in the case of the hydrate, by a cooperative effect of the water molecules. The chains are linked together by weaker N‒H···N hydrogen bonds to form the crystal.

GRAPHICAL ABSTRACT

Keywords:

• α-Aminophosphonic acids
• hydrogen bonding
• molecular and crystal structure
• organophosphorus compounds

Acknowledgments

This investigation has been financially supported by Institutional Strategy of the Excellence Initiative at LMU Munich—LMUexcellent.