Complexes of Amino Acids, EDTA, and Related Compounds

COMPLEXES OF AMINO ACIDS, EDTA, AND RELATED COMPOUNDS 

To examine the effects of coordination and hydrogen bonding, Nakamoto el al. made extensive IR measurements of the COO stretching frequencies of various metal complexes of amino acids in D2O solution, in the hydrated crystalline state, and in the anhydrous crystalline state. The results showed that, in any one physical state, the same frequency order is found for a series of metals, regardless of the nature of the ligand. The antisymmetric frequencies increase, the symmetric frequencies decrease, and Ihe separation between the two frequencies increases in the following order of metals  

Although there a Ve several exceptions to this order, these results generally indicate that the effect of coordination is still the major factor in determining the frequency order in a given physical state. The above frequency order - - thi metal-oxveen interaction since the COO 

To give definitive band assignments in the low frequency region of 6i5(glycino) complexes of Ni(ll), Cu(ll), and Co(Il), Kincaid and Nakamoto carried out H-D, Ni- Ni, and Cu- Cu substitu- 

Glycine also coordinates to the Ft(ll) atom as a unidentate ligand  

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