Mn(II)/Ni(II) Complexes Based on 5-Methyl-1H-pyrazole-3-carboxylic Acid: Syntheses, Structures, Electrochemical and Luminescent Properties

In the absence/presence of chelating N ancillary ligand, 2,2'-bipyridine (2,2'-bpy), treatment of 5-methyl-1H -pyrazole-3-carboxylic acid (H(2)MPCA) with corresponding Mn(II)/Ni(II) metal salts afforded two complexes, [Mn(HMPCA)(2)(H2O)(2)] (1) and [Ni(HMPCA)(2)(2,2'-bpy)]center dot 2H(2)O (2). In mononuclear complexes 1 and 2, each metal ion locates in a distorted octahedral geometry, and the HMPCA(-) ligands in 1 and 2 both act as a N, O-chelating ligand. In 1, by the function of intermolecular N-H center dot center dot center dot O and O-H center dot center dot center dot O hydrogen bonds, the independent [Mn(HMPCA)(2)(H2O)(2)] units are packed into a porous 3D supramolecular structure with 1D nanotube. In 2, the mononuclear components [Ni(HMPCA)(2)(2,2'-bpy)] and the lattice water molecules are interlinked via intermolecular O-H center dot center dot center dot O and NH center dot center dot center dot O hydrogen bonds, generating a 1D chainlike structure, which is linked to adjacent ones through intermolecular pi center dot center dot center dot pi interactions forming a 3D supramolecular architecture. The electrochemical and luminescent properties of complexes 1 and 2 have also been investigated. CCDC: 2033945, 1; 2033946, 2.

Automated summary

In the absence/presence of chelating N ancillary ligand, treatment of 5-methyl-1H-pyrazole-3-carboxylic acid with corresponding Mn(II)/Ni(II) metal salts yielded two complexes with distinct molecular networks, leading to the formation of a 3D supramolecular structure and a chainlike structure, respectively. The structures of the two complexes were analyzed, revealing different coordination geometries for each metal ion and the role of intermolecular hydrogen bonds in shaping their supramolecular architectures. Additionally, the electrochemical and luminescent properties of the complexes were investigated, providing insights into their potential applications.