A Novel Centrosymmetric Fe(III) Complex with Anionic Bis-pyrazolyl-s-triazine Ligand; Synthesis, Structural Investigations and Antimicrobial Evaluations

Reaction of 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (MBPT) pincer ligand with FeCl3 in acidic medium (1:1 v/v) afforded the [Fe(BPT)Cl-2(CH3OH)] complex of the hydrolyzed monobasic ligand: 4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2(1H)-one (HBPT). In this complex, the Fe(III) ion is hexacoordinated with one anionic pincer ligand unit (BPT-1), two chloride ions, and one coordinated methanol molecule. It crystallized in the monoclinic crystal system and centrosymmetric P2(1)/c space group with Z = 2 and unit cell parameters of a = 7.309(2) angstrom, b = 25.461(8) angstrom, c = 9.918(3) angstrom and beta = 102.646(7)degrees. The structure of this complex is stabilized by C-H horizontal ellipsis Cl intramolecular hydrogen bonding interactions with donor acceptor distances ranging from 3.577(3)-3.609(3) angstrom while its supramolecular structure is controlled by intermolecular O-H horizontal ellipsis O, O-H horizontal ellipsis N, and C-H horizontal ellipsis Cl hydrogen bonding interactions. Hirshfeld analysis of molecular packing indicates that the percentages of the Cl horizontal ellipsis H, C horizontal ellipsis O, O horizontal ellipsis H, C horizontal ellipsis C, H horizontal ellipsis C, and N horizontal ellipsis H contacts are 21.1, 1.7, 10.2, 2.1, 8.6, and 10.4%, respectively. The nature and relative strength of the different coordination interactions in the [Fe(BPT)Cl-2(CH3OH)] complex are discussed based on atoms in molecules theory. Antimicrobial evaluations indicated that the [Fe(BPT)Cl-2(CH3OH)] complex showed moderate antibacterial and antifungal activities compared to amoxicillin and ampicillin antibiotics as standard drugs.