In situ IR monitoring of complexation reaction between 2,6-bis(3,5-dimethylpyrazoyl)pyridine and some metal ions

In situ complexation reactions between 2,6-bis(3,5-dimethylpyrazoyl)pyridine (bdmpp) and some transition metals (Cu2+, Co2+ and Ni2+) were studied with a new method in liquid cell using FT-IR. In this method, the FT-IR spectrum of the solution of ligand was defined as a background, and then the changes in the FT-IR spectra by the addition of the metal salts were investigated. This method allows one to obtain the spectra of the ligand-metal complex before yielding the solid-state product. Complexation ratios (M/L) of these metals with bdmpp were found 1/1, 1/2 and 1/2, for Cu, Co and Ni, respectively. Studying with Mg2+ and Ca2+ ions showed that there were no interaction between bdmpp and these metal ions in methanol.