Synthesis and photophysical properties of dinuclear organometallic rhenium(I) diimine complexes linked by pyridine-containing macrocyclic phenylacetylene ligands

摘要

Two novelpyridine-containing hexagonal phenylacetylenic macrocyclic ligands have been synthesized from Pd-catalyzed cross-coupling or Cu-catalyzed oxidative coupling reactions.These ligands have been subsequently used to prepare dinuclear 4,4'-di-tert-butyl-2,2'-bipyridine Re(I0 tricarbonyl complexes.Both ligands and complexes show strong luminescence in room-temperature solution.There is no concentration dependence in the ~1H NMR spectra for these lignads and complexes,which rules out ground-state self-association.However,both of the free ligands wxhibit concentration-dependent fluorescence.The fluorescence bands of the ligands are red-shifted with increasing concentration,and this behavior is ascribed to the formation of excimers in the excited states.In contrast,both of the organometallic complexes do not exhibit any concentration-dependent luminescence.