Investigating the CPL-Structure Dependence in Arylalkynylpyridyl-Triazacyclononane Sensitized Nine-Coordinate Europium(III) Complexes.

A series of novel arylalkynylpyridyl-triazacyclononane sensitized macrocyclic europium(III) complexes (EuL) was prepared, and their circularly polarized luminescence characterized in terms of the spectral profile and dissymmetry factor (glum). The series was engineered based on previously reported isostructural complexes by a controlled introduction of structural modifications at different positions with respect to the coordination environment of the emitting europium(III) center. It was established that only those structural features of the macrocyclic ligand that were proximal to the europium(III) center affected CPL properties. These findings could help shape the development of a new class of purpose-built EuL complexes compatible with CPL-unaffecting complex-stage functionalization to introduce advantageous structural features for applications in life and material sciences.