Crystal structures and charge distribution of partially-fluorinated β-diketonate copper(II) complexes based on Hirshfeld surface analysis and DFT calculations

Two partially-fluorinated coordination complexes, C30H20CuF2O4 (1) and C30H18CuF4O4 (2), were prepared and the corresponding crystals, 1 with a benzene solvate (1 center dot C6H6) and 2, were obtained from a benzene-dichloromethane solution. The crystallographic studies and the Hirshfeld surface analysis of the crystals showed the metal center dot center dot center dot pi interactions through an electrophilic property of the Cu ions and the remarkable CH center dot center dot center dot pi interactions between the phenyl substitutions; the most important contributions for the crystal packing for 1 in 1 center dot C6H6 are from the C center dot center dot center dot H/H center dot center dot center dot C (36.8%), H center dot center dot center dot H (34.0%), and F center dot center dot center dot H/H center dot center dot center dot F (10.4%) interactions but those for 2 are from the H center dot center dot center dot H (28.8%), F center dot center dot center dot H/H center dot center dot center dot F (22.9%), and C center dot center dot center dot H/H center dot center dot center dot C (19.2%). A density functional theory (DFT) calculation using the optimized structures from the crystal data clearly showed the proportion of the electron-withdrawing effects of the fluorine substitution and the corresponding effects on the central metal ions and the other aromatic rings. (C) 2020 Elsevier Ltd. All rights reserved.