Synthesis and characterization of a manganese(II) complex containing N(<i>sp</i>²)₄-donor Schiff base ligand and interaction toward biomacromolecules

In this work, an N₄-donor Schiff base ligand, <i>N</i>,<i>N</i>'-(propane-1,2-diyl)bis(1-phenyl-1-(pyridin-2-yl)methanimine) (PPPM) and its Mn(II) complex, [Mn(PPPM)(OAc)₂]·3H₂O (<b>1</b>), were prepared and identified by elemental analysis, FT-IR, ¹H NMR spectroscopy as well single-crystal X-ray diffraction. X-ray structure analysis of <b>1</b> revealed a distorted square-face bicapped trigonal prism geometry around manganese atom with MnN₄O₄ environment containing an N₄-donor PPPM and two O₂-donor acetato ligands. The ligand has a chiral center on carbon atom which leads to the formation of a racemic mixture of complex <b>1</b>. In the crystal structure of complex, intermolecular hydrogen bonds form R₄⁴(8) hydrogen bond motifs. The ability of two optical isomers of PPPM ligand and manganese complex to interact with 10 selected biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS, Top II, B-DNA) was investigated by docking studies. These studies revealed that PPPM^R,S and <b>1</b>^R,S isomers can bind to these molecules better than doxorubicin (except B-DNA).