Structure-Directing Weak Interactions with 1,4-Diiodotetrafluorobenzene Convert One-Dimensional Arrays of [MII(acac)2] Species into Three-Dimensional Networks

The complexes [MII(acac)2] (M = Cu 1, Pd 2, Pt 3; Hacac = acetylacetone) and 1,4-diiodotetrafluorobenzene (FIB) were cocrystallized in CHCl3–MeOH solutions to form adducts (1–3)·FIB, whose structures were studied by X-ray diffraction. The association leads to unification of the three structures, thus demonstrating the potential of the isostructural Cu/Pd/Pt exchange for construction of supramolecular systems involving [MII(acac)2] complexes. In the crystal structures of (1–3)·FIB, the intermolecular bifurcated halogen bonding I···μ2-(O,O) and noncovalent interactions M···C were identified and then studied by density functional theory calculations and topological analysis of the electron density distribution within the framework of the QTAIM method at the M06/DZP-DKH level of theory. Apart from these unconventional interactions, two types of classic hydrogen bonding, viz. the C–H···I–C and C–H···F–C contacts between Me groups and halogen atoms of FIB, were detected. Collectively all these noncovalent structure-directing interactions provide conversion of one-dimensional arrays of the [MII(acac)2] species into three-dimensional networks.