Self-assembled Mn(III)-salen type complexes as catalysts for degradation of lignin analogues

摘要

Mn(III) complexes 1-3, incorporating dianionic hexadentate Schiff base ligands and different anions (perchlorate for 1, acetylacetonate for 2 and dicyanamide for 3) have been synthesized and characterized by elemental analysis, ESI mass spectrometry, IR spectroscopy, room temperature magnetic and molar conductivity measurements. Com- plex 3 was also crystallographically characterized. The catalytic studies for the use of these complexes as oxygen activators for the selective oxidation of the lignin model compound veratrylalcohol (VA) have been studied. H2 O2 and O2 have been alternatively tested as oxidants. Yields up to 30% of VA conversion to veratrylaldehyde have been achieved at room temperature in presence of air fow using 0.5% of catalyst.