Supramolecular architecture of Mn(II) complex with 5,5´-dimethyl-2,2´-bipyridine and 4-hydroxybenzoic acid: Synthesis, crystal structure, Hirshfeld surface analyses, catalytic and antimicrobial activities

Abstract

A novel complex [Mn(5,5´-dmbipy)2Cl2](4-hba)2 (1) (5,5´-dmbipy=5,5´-dimethyl-2,2´-bipyridine and 4-hba=4-hydroxybenzoic acid) was successfully synthesized using methanol by steam reflux. The complex is characterized using SC-XRD, IR, UV and thermogravimetric analysis. Single crystal X-ray analysis of 1 indicates a distorted octahedral coordinated Mn2+ centre with two molecules of 5,5´-dmbipy and two chlorine ions and the presence of two uncoordinated 4-hba in the complex. The two chlorine atoms (Cl1 and Cl2) form intermolecular H-bonding with 4-hba. The complex crystallizes in monoclinic space group P21/c forming a helical like 1D polymeric supramolecular architech through H- bonding. Presence of halogen-hydrogen bond C(sp2)-OH—Cl-M between uncoordinated -OH and Cl ion in 1 significantly provides a path of extending supramolecular network forming a unique architect of the complex. Interestingly, presence of pyridine-benzene system forming π-π stacking is confirmed from SC-XRD. Hirshfeld surface analysis is carried out to explore the noncovalent interactions in the crystal. Mn3O4 nanoparticles synthesized from complex 1 are characterized using PXRD and HRTEM, and successfully employed as catalyst for the degradation of dyes. Both complex 1 and Mn3O4 nanoparticles show appreciable biological activities.