Ruthenium (III) complexes derived from complexation of metal ion with azomethine linkage of chitosan biopolymer Schiff base ligand – Spectral, crystalline characterization and anti-oxidant activity

The chelation properties of chitosan primarily from its molecular structure and it has a high density of amino (-NH₂) and hydroxyl (-OH) groups. These groups can act as binding sites, enabling chitosan molecule to chelate with various metal ions through coordination bonds. Ruthenium metal complexes Ru[Chi4Hy3mbd(H2O)2].(Cl2)2, Ru[Chi2Hybd(H2O)2].(Cl2)2 and Ru[Chi2Hy3mbd(H2O)2].(Cl2)2 were synthesized by complexation reaction of chitosan Schiff base bidentate ligands. The synthesized metal complexes were characterized by 1H-NMR, ESR spectroscopy and the crystalline, morphological changes were examined. The in-vitro antioxidant property of these ruthenium (III) complexes has been discussed extensively. From antioxidant date, good free radical scavenging activities of these metal complexes were shown on DPPH and LPO free radicals.

壳聚糖（chitosan）的螯合性能主要源于其分子结构，其具有高密度的氨基（-NH₂）与羟基（-OH）基团。这些基团可作为结合位点，使壳聚糖分子能够通过配位键与多种金属离子发生螯合作用。通过壳聚糖希夫碱（Schiff base）双齿配体的配位反应，合成了三种钌金属配合物：Ru[Chi4Hy3mbd(H₂O)₂]·(Cl₂)₂、Ru[Chi2Hybd(H₂O)₂]·(Cl₂)₂以及Ru[Chi2Hy3mbd(H₂O)₂]·(Cl₂)₂。采用1H-核磁共振波谱（1H-NMR）、电子自旋共振波谱（ESR）对合成的金属配合物进行了表征，并对其结晶性与形貌变化进行了考察。本研究对该类三价钌配合物的体外抗氧化性能展开了详尽讨论。从抗氧化实验数据可知，此类金属配合物对二苯基苦基苯肼（DPPH）与脂质过氧化物（LPO）自由基均表现出优异的自由基清除活性。