Synthesis, structures and luminescence of multinuclear silver(i) pyrazolate adducts with 1,10-phenanthroline derivatives

A set of silver(i) 3,5-bis(trifluoromethyl) pyrazolate adducts with 1,10-phenanthroline (L2), 2,9-dimethyl-1,10-phenanthroline (neocuproine, L3) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, L4) was synthesized starting from trimeric silver pyrazolate Ag3Pz3. Reactions with sterically hindered L3 and L4 cause the destruction of the original trimeric core, yielding a dinuclear Ag2Pz2 cycle with an unprecedented chair configuration for L3, while bathocuproine L4 leads to the drastic rearrangement of the silver pyrazolate core into cationic Ag(L4)2 and anionic Ag5Pz6 subunits. All complexes obtained exhibit phosphorescence in the solid state. Time-dependent density functional theory calculations demonstrate their different possible emission processes, explaining their emission behavior as well as their lifetimes. © 2019 The Royal Society of Chemistry.