Generation, spectroscopic characterization and antioxidant activity of tetracoordinate and hexacoordinate complexes of diethylgermanium(IV) of relatively sterically undemanding N-protected amino acids and sterically demanding heterocyclic β-diketones containing radical sensitive Ge-O bond
Two new sets of diethylgermanium(IV) complexes of the types Et2GeA2 and Et2GeB2 have been generated by the reactions of diethylgermanium(IV) dichloride with sodium salts of N-protected amino acids (AH) [where AH = , R = -CH(CH3)C2H5: A1H, R = -CH2CH(CH3)2: A2H, R = -CH(CH3)2: A3H] and with sodium salts of sterically demanding heterocyclic β-diketones (BH) [where BH = , R’ = -C6H5: B1H, R’ = -p-(Cl)C6H4: B2H, R’ = -CH3: B3H, R = -C2H5: B4H], respectively in 1:2 molar ratios in refluxing dry benzene. Plausible structures of these complexes were suggested on the basis of physico-chemical and spectroscopic studies. It is suggested that the complexes of the types Et2GeA2 and Et2GeB2 contain four coordinated and six coordinated germanium centers, respectively. The ligands and organogermanium(IV) complexes were evaluated for their free radical scavenging activity by DPPH method. These compounds/complexes demonstrate potential antioxidant activity.