Solvent and anion effects on the organization of a luminescent [2 + 2] BODIPY/Ag(i) metallamacrocycle in the crystalline state

Abstract

A novel BODIPY derivative bearing peripheral benzonitrile units at positions 3 and 5 has been designed, synthesized and characterized both in solution and in the solid state by X-ray diffraction on single crystals. Its reaction with AgX salts (X⁻ = AsF₆⁻, BF₄⁻, ClO₄⁻) was investigated at room temperature using different solvent systems. The resulting assemblies all incorporate the same type of [2 + 2] [Ag₂(BODIPY)₂]²⁺ metallamacrocycles. The arrangement of the cyclic motif in the crystalline state has been shown to be dependent on the nature of the anion X⁻ and the solvents employed. The macrocycles organize into dimers or extended networks due to interactions with the anion or solvent molecules acting as bridges, as well as, in some cases, Ag–π interactions with the pyrrolic system of the BODIPY. For all structures, the anions are located inside the cavity of the metallamacrocycle and hydrogen bonded to the inner CH of the benzonitrile moieties. All compounds are emissive in the crystalline state and display emission bands between 750 and 800 nm.