Dear Dr's
I have a Schiff base derived from salicylaldehyde, how to know the OH make coordinate or covalent bond with metal. in another word OH group loss H+ or not.
The stability of the complex is partly because the H of the oxime forms an hydrogen bond with with oxygen of the phenoxylate, therefore it releases H+ to compensate for the charge of the cation, which leads to neutral complexes. However, complexation of Fe(III) is more complex, forming clusters, but iron (II) complexates in a simpler manner, forming a red product at pH around 7. At very high pH, the oximes can deprotonate as well, which tends to break the complex.
1. You can confirm it by NMR spectra. The phenolic OH peak will disappear. Additionally you can observe a shift of imine proton in the NMR spectra.
2. In FTIR the OH signal will disappear. The imine proton signal also shift to lower value in comparison to free ligand.
Thank you alot.
but H-NMR analysis not suitable for para magnetic complexes
the sharpness decrease not disappear; so it form covalent
all reaction at neutral medium
the structure didn't have an oxime as in attached file
You didn't mention in your query about the metal you are looking for. According to me FTIR is the best solution for paramagnetic compound.
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