Structural analysis and physico-chemical characterization of mononuclear manganese(II) and polynuclear copper(II) complexes with pyridine-based alcohol

Abstract Two novel manganese(II) and copper(II) complexes, mononuclear [Mn(H 2 O) 2 (2-(CH 2 ) 2 OHpy) 2 ](NO 3 ) 2 ( 1 ) and polynuclear [Cu(SO 4 )(2-(CH 2 ) 2 OHpy) 2 ] n ( 2 ), based on 2-(hydroxyethyl)pyridine (2-(CH 2 ) 2 OHpy) were synthesised and fully characterised using X-ray structure analysis as well as spectroscopic, magnetic and thermal methods. Both central metal ions Mn(1) and Cu(1) are coordinated by two N,O-donor 2-(CH 2 ) 2 OHpy ligands and possess an almost perfect octahedral geometry (a chromophore of {MN 2 O 4 } type). The coordination sphere of Mn(II) is completed by two molecules of water, whereas, in polynuclear complex 2 , Cu(II) atoms are linked along the a crystallographic direction by bridging sulfate ligands in a μ 2 -κ 2 binding mode to form chains. The intermolecular interactions in 1 and 2 have been interpreted in view of the 3D Hirshfeld surface analysis and associated 2D fingerprint plots. Furthermore, the complexes have been tested with ABTS + assay in order to assess their antioxidant activity. In addition, the IC 50 values calculated for 1 and 2 revealed that the complexes show a higher antioxidant activity than corresponding ligand.