Supramolecular aggregation of Ni(salen) with (C6F5)2Hg and [o-C6F4Hg]3

Abstract

As part of our ongoing interest in the supramolecular chemistry of fluorinated organomercurials, we have investigated the interaction of bis(pentafluorophenyl)mercury ((C₆F₅)₂Hg), and trimeric (perfluoro-o-phenylene)mercury ([o-C₆F₄Hg]₃), with nickel(II) N,N′-bis(salicylidene)ethylenediamine) (Ni(salen)). While solution studies monitored by UV-VIS spectroscopy suggest that Ni(salen) interacts with the trinuclear mercury complex in solution, the 1 : 1 adduct (Ni(salen)-(C₆F₅)₂Hg) and the 1 : 1 adducts Ni(salen)-[o-C₆F₄Hg]₃ and [Ni(salen)-[o-C₆F₄Hg]₃-THF-H₂O] can be obtained by slow evaporation of solutions containing the two building blocks. While arene–fluoroarene and hydrogen bonding interactions, as well as interactions between mercury and the salen ligand are the predominant forces responsible for the formation of these adducts, Ni(salen)-[o-C₆F₄Hg]₃ and [Ni(salen)-[o-C₆F₄Hg]₃-THF-H₂O] also display short Ni–Hg separations consistent with the presence of metallophilic interactions. Quantum theory of atoms in molecules (QTAIM) analyses of the Ni–Hg interactions in these adducts finds that these interactions are dominated by electrostatic and dispersion forces, despite featuring non-negligible covalent contributions.