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 (L-2), 2,9-dimethyl-1,10-phenanthroline (neocuproine, L-3) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, L-4) was synthesized starting from trimeric silver pyrazolate Ag(3)Pz(3). Reactions with sterically hindered L-3 and L-4 cause the destruction of the original trimeric core, yielding a dinuclear Ag(2)Pz(2) cycle with an unprecedented chair configuration for L-3, while bathocuproine L-4 leads to the drastic rearrangement of the silver pyrazolate core into cationic Ag(L-4)(2) and anionic Ag(5)Pz(6) 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.