Phosphorescent iridium(III) complexes bearing l-alanine ligands: Synthesis, crystal structures, photophysical properties, DFT calculations, and use as chemosensors for Cu2+ ion

Two neutral iridium complexes with l-alanine as ancillary ligands, (thp)2Ir (l-alanine) (Ir1) (thp = 2-(thiophen-2-yl)pyridine) and (btp)2Ir (Ir2) (btp 2-(benzo[b]thiophen-2-yl)pyridine) were synthesized investigated. The solid-state structures of the developed Ir1 Ir2 authenticated by single X-ray diffraction. Ir(III) exhibit intense yellow red emission respectively high quantum efficiencies (Φem 0.88 for Ir1, Φem 0.29 Ir2) in oxygen-free acetonitrile solution at room temperature. Theoretical calculations carried out to provide a further study orbital distributions electronic states two complexes. displayed significant reversible phosphorescence quenching upon binding Cu2+ ion stoichiometry was approximately 1:1.1H NMR titration experiments indicated that coordination nitrogen atoms ligands induce variations optical signals. This work showed new phosphorescent probes based on could be realized introducing simple amino acid ligands.