Quantum mechanics

Quark

Catalysis

Enantioselective synthesis

Enantiomer

Photochemistry

Materials science

Enantiopure drug

Nuclear physics

Nambu–Jona-Lasinio model

Quantum yield

Stereochemistry

Physics

Microstrip

Organic chemistry

Optics

Luminescence

Fluorescence

Circular polarization

Excited state

Crystallography

Chirality (physics)

Chemistry

Chiral symmetry breaking

Optoelectronics

Journal of the American Chemical Society

The chiral resolution of a kinetically inert molecular ruby [Cr(dqp)2]3+ (1, dqp = 2,6-di(quinolin-8-yl)pyridine) displaying strong dual light emission at room temperature has been achieved. The wrapped arrangement of the six-membered dqp chelating ligands around the Cr(III) provided nonplanar helical conformations leading to the diastereoselective assembly of chiral bis-tridentate monometallic Cr(III)-helix. The PP-(+)-[Cr(dqp)2]3+ and MM-(-)-[Cr(dqp)2]3+ enantiomers could be separated and isolated by using cation-exchange chromatography and subsequent salt-metathesis with KPF6. X-ray crystallographic analysis based on Flack parameters assigned the absolute configurations of the two enantiomers. Circularly polarized luminescence (CPL) spectra showed two polarized emission bands within the NIR region corresponding to the characteristic metal-centered spin-flip Cr(2E → 4A2) and Cr(2T1 → 4A2) transitions with exceptionally high dissymmetry factors, |glum|, of 0.2 and 0.1, respectively, which are comparable to those reported for rare-earth chiral complexes. Photophysical properties also revealed an extremely long excited-state lifetime of 1.2 ms and a high quantum yield of 5.2% at room temperature in water. These properties make [Cr(dqp)2]3+ an ideal sensitizer for the preparation of enantiopure luminescent supramolecular energy-converting devices and also open up the possibility of using chiral Cr(III) chromophores for the construction of NIR-CPL materials and polarized photonic devices based on earth-abundant metals.

Chiral Molecular Ruby [Cr(dqp)<sub>2</sub>]<sup>3+</sup> with Long-Lived Circularly Polarized Luminescence

Chiral Molecular Ruby [Cr(dqp)2]3+ with Long-Lived Circularly Polarized Luminescence

Chiral Molecular Ruby [Cr(dqp)₂]³⁺ with Long-Lived Circularly Polarized Luminescence