Unprecedented {d z 2 -Cu II O 4 }⋯π-hole interactions: the case of a cocrystal of a Cu(II) bis-β-diketonate complex with 1,4-diiodotetrafluoro-benzene.

Cocrystallization of a bis[1-(4-pyridyl)butane-1,3-dionato]copper(II) (1) complex and 1,4-diiodoperfluorobenzene in the presence of pyridine yields a 1 : 1 cocrystal where both the σ and π-holes of 1,4-diiodoperfluorobenzene play a role. The crystal structure shows short arene CuO 4 ⋯π-hole stacking contacts, where the {d z 2 -Cu II O 4 } moiety functions as an integrated five-center π-hole acceptor. DFT calculations combined with quantum theory of atoms-in-molecules and noncovalent interaction plot analyses corroborated the structure-defining role of the {d z 2 -Cu II O 4 }⋯π-hole contacts.