Preparation, characterization and biological activity of Schiff base compounds derived from 8-hydroxyquinoline-2-carboxaldehyde and Jeffamines ED®

Polyethers with 8-hydroxyquinolin-2-yl end groups (HOQCHN–POE–NCHQOH) were prepared by reaction between polyethers having amino end groups (Jeffamines ED®) and 8-hydroxyquinoline-2-carboxaldehyde. The HOQCHN–POE–NCHQOH polymers were characterized by size-exclusion chromatography, UV, IR, 1H and 13C NMR spectroscopy, and MALDI-TOF mass spectrometry. The complexation between HOQCHN–POE–NCHQOH and Fe3+ was studied by UV, IR spectroscopy and differential scanning calorimetry. The UV-irradiation of the complexes caused photodegradation of the polyether chains. It was shown that HOQCHN–POE–NCHQOH had high efficacy on remedying iron-deficient maize plants and exhibited very low-antibacterial activity towards non-pathogenic soil bacteria (B. subtilis).