Study of indium complexes with aminopolymethylenephosphonic acids by IR spectroscopy method

IR spectra of crystal samples of indium complexes with ethylene-diaminetetramethylenephosphonic acid (1) and oxy-bis (ethylenenitrile) tetramethylenephosphonic acid (2) are studied. It is found that complexing takes place due to metal interaction with nitrogen and oxygen atoms. A relative part of indium complexes with 2, where nitrogen atom is coordinated with metal decreases with pH decrease. Crystal samples of indium complex with 2 are the mixture of at least two forms differing in nitrogen atom coordination and in oxygen-metal bond character