Near Infrared-Circularly Polarized Luminescence/Circular Dichroism Active Yb(III) Complexes Bearing Both Central and Axial Chirality.

In this contribution, we present new NIR-CPL/CD active Yb(III) complexes, which are synthesized by combining two ligands characterized by different types of chirality: central and axial chirality. The ligand bearing central chirality is represented by the neutral trans-N,N'-bis(2-pyridylmethylidene)-1,2-(R,R or S,S) cyclohexanediamine (L), whereas the axial ligand is 1,1'-binaphthyl-2,2'-diol (BINOL-H2). A combined 1H NMR, thermodynamic (spectrophotometric titrations), and theoretical (DFT structural calculations) study is presented, revealing the high stability in the methanol solution of the homochiral C2-symmetric anionic [YbL(BINOL)2]- complexes, in which the two labile BINOLate molecules exhibit the same stereochemistry (R or S). The metal ion-related optical and chiroptical properties of the complexes in the near-infrared spectral region are here presented and discussed: while the axial chirality dominates the circularly polarized luminescence features, the NIR-CD signal is affected by both chiral elements.