The relevance of the fluorine interactions in the supramolecular structure of a complex constructed from copper(II) hexafluoroacetylacetonate and the 4′-(3-pyridyl)-2,2′:6′,2″-terpyridine ligand. Novel C–F/π synthons involving the π-system of the terpyrid

Reaction of 4′-(3-pyridyl)-2,2′:6′,2′′-terpyridine (pyterpy) with Cu(hfacac)2 (hfacac = hexafluoroacetylacetonate) led to the formation of the novel compound [Cu3(hfacac)4(μ-pyterpy)2][Cu(hfacac)3]2 (1). The structure is composed of a trinuclear [Cu3(hfacac)4(μ-pyterpy)2]2+ cation and two [Cu(hfacac)3]− anionic species. The cation consists of a chain of three CuII atoms connected by bridging pyterpy ligands. The [Cu(hfacac)3]− anions have the hfacac ligands coordinated in their usual chelating manner through their carbonyl O donors. Besides the coulombian forces, the ionic species are fixed by C–H⋯O, C–H⋯F, F⋯F and a variety of unusual inter-ion C–F⋯π interactions that control the packing motif. These π-interactions involve the terpyridine groups from the pyterpy ligand and the five-membered rings of the chelating hexafluoroacetylacetonate anions.