Luminescent [Cu4I4] aggregates and [Cu3I3]-cyclic coordination polymers supported by quinolyl-triazoles

Quinolyl-1,2,3-triazole ligand supported [Cu4I4] stair-step aggregates [Cu4I4(L1)2] (1), [Cu4I4(L2)2] (2), [Cu4I4(L3)2] (3), [Cu4I4(L4)2] (4), [Cu4I4(L5)2] (5), and six-membered [Cu3I3] metallacycle based coordination polymers [Cu2I2(L6)]n (6) and [Cu2I2(L7)]n (7) (ligands are 2-((1H-1,2,3-triazol-1-yl)methyl)quinoline (L1), 2-((4-alkyl-1H-1,2,3-triazol-1-yl)methyl)quinoline (propyl, butyl and isobutyl for L2, L3 and L4, respectively) and 2-(1-((quinolin-2-yl)methyl)-1H-1,2,3-triazol-4-yl)alcohol (methanol, ethanol and propanol for L5, L6 and L7, respectively)) have been prepared and characterized by single-crystal X-ray diffraction (XRD), powder XRD, photoluminescence spectroscopy and thermogravimetric analysis. Complexes 1-5 are stair-step [Cu4I4] aggregate structures supported by two quinolyl-triazole hybrid ligands. Complexes 6 and 7 are rare cyclic [Cu3I3] aggregate-based 1-D coordination polymers. All ligands adopt a common tridentate-bridging coordination mode. These complexes are strongly luminescent with a yellow emission (500-700 nm) in the solid state.