Fluorinated acylpyrazolone ligand (HQ PhF ): Synthesis, structural characterization and DFT studies of three new divalent cobalt and zinc complexes

Three new mononuclear complexes, including two cobalt(II) complexes, [Co(OH2)2(QPhF)2] 1 and [Co(OH2)2(QPhF)2]·2DMF 2, along with one zinc(II) complex, [Zn(OH2)2(QPhF)2] 3, were synthesized from the reactions of 4-(4-fluorobenzoyl)-3-methyl-1-phenylpyrazol-5-one (HQPhF) with CoCl2·6H2O and Zn(NO3)2·6H2O at room temperature. These compounds were characterized by FT-IR and UV–visible spectroscopy, single-crystal X-ray diffraction and DFT studies. Crystallographic data showed that each compound crystallizes in a monoclinic system with 1 and 3 crystallizing in the same space group C2/c(15) with unit cell parameters a = 21.451(4) Å, b = 10.790(2) Å, c = 16.575(3) Å, α = γ = 90°, β = 128.90(3)° for 1 and a = 21.4553(9) Å, b = 10.8147(3) Å, c = 16.5330(7) Å, α = γ = 90°, β = 128.833(3)° for 3. 2 crystallizes in P21/c with a = 12.8225(5) Å, b = 15.5048(6) Å, c = 10.0793(4) Å, α = γ = 90° and β = 109.977(5)°. In all structures, the metal centers adopt distorted octahedral geometries, built by four oxygen atoms from two QPhF- anions and two from H2O molecules. In compound 2, two DMF are present as lattice solvent molecules. The presence of intermolecular interactions (π–π stacking, hydrogen) and intermolecular strong hydrogen bonds (O–H···F and O–H···N) generates a 1D (compounds 1 and 3) or 2D (compound 2) supramolecular network. DFT studies reveal that changing the metal ion from Co(II) to Zn(II) decreases reactivity and increases the stability of 3.