Stimuli-Responsive Multifunctional Iridium(III) Complex Exhibiting Thermo-, Vapochromism, and Double Catalytic Activity.

Multifunctional compounds with properties that may be triggered by different external stimuli are highly desirable yet challenging in their design and synthesis. Herein, we report a cyclometalated iridium(III) complex based on bulky 1,2-diphenylphenanthroimidazole (C^N) that can easily change its molecular geometry from trigonal-bipyramidal to octahedral or from a monomeric to dimeric state in response to external stimuli (temperature and solvent variations). The extensive characterization including variable-temperature H NMR, single-crystal and powder X-ray diffraction corroborated by density functional theory calculations strongly indicates that the thermochromic behavior of the complex is attributed to the dimer-monomer transformations both in solution and in the solid state.