The infrared spectra of chelates of divalent and trivalent metals with nitrilotriacetic acid

Infrared data for the chelates of some divalent and trivalent metals with nitrilotriacetic acid are reported. This study embraces 1:1, 1:2 and 2:3 chelates, in acid form or as the sodium salt. The metals investigated are Mg, Ca, Sr, Ba, Zn, Cd, Hg, Pb, Co, Ni, Cu, Cr, Mn, Fe, Bi, Y and La. The stretching frequencies for the CH2, COO and CN functions in the chelates are sensitive to bonding, and are diagnostic of chelation. An interpretation of bands appearing in the 1600-1560 cm−1—previously observed by other workers, but never discussed—is proposed. Comparisons are made with the corresponding EDTA chelates. Some correlations axe attempted.