Synthesis, crystal structure, DFT studies and Hirshfeld surface analysis of Manganese(II) and Cadmium(II) coordination polymers of 2-aminopyridine and dicyanamide

Abstract

Mn(II) and Cd(II) metal salts reacted with dicyanamide and 2-aminopyridine resulted in the formation of the ligand-rich linear polymeric chain structures [M(dca)2(2-Ampy)2]n (dca = dicyanamide, 2-Ampy = 2-Aminopyridine; M = Mn (1) or Cd (2)), of the same dimensionality, in which the metal centers are μ1,5-bridged by the dca anions. The complexes were characterized by elemental analysis, IR spectroscopy, UV–vis spectroscopy, thermal analysis and single crystal X-ray structure analysis. These coordination polymers crystallize in the Monoclinic space group Cc. The 3D crystal packing structure results from a combination of N—H/H—-N interactions followed by CH—π stacking interactions. Hirshfeld surface (HS) analysis of the polymers was undertaken to investigate further the intermolecular interactions. DFT calculations on 1 and 2 demonstrated a good correlation between the experimental and theoretical data. The in vitro antimicrobial activity of the manganese complex against selected micro-organisms is also reported.