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 sixmembered dqp chelating ligands around the Cr(III) provided non-planar 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 saltmetathesis 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(2 E→ 4 A2) and Cr(2 T1→ 4 A2) transitions with exceptionally high dissymmetry factors, glum, of 0.2 and 0.1, respectively, which are comparable to those reported for rareearth 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 earthabundant metals.

The synthesis and characterization of an enantiopure superhelicene nanographene is reported in which two saddle-shaped and one planar hexabenzocoronene (HBC) units are arranged in a helicoidal shape to form an undecabenzo[7]carbohelicene. The described compound is the first fully π-extended [7]helicene. Racemic resolution of the helical nanographene permitted analysis of the chiroptical properties and revealed dissymmetry factors in the range of 2×10 both in the absorption and in the emission measurements. Remarkably, non-linear photophysical analysis demonstrated a two-photon absorption cross-section of 870 GM at 800 nm and a perfect overlap between linear, non-linear, and chiral emissions.

The authors wish to cite an additional paper. In 2002, Doris and co-workers reported the reduction of a,b-unsaturated ketones in the presence of [Cp 2 TiCl] and MeOH via free-radical chemistry. This observation is closely related to that reported by the authors the same year on the reduction of carbon radicals in the presence of [Cp 2 TiCl] and water but was not cited in the present article. The authors apologize for the oversight. Reference [4] should therefore read as follows: [4] a) b) for related observations on the reduction of a,b-unsaturated ketones in the presence of [Cp 2 TiCl] and MeOH, see: L. Moisan, C. Hardouin, B. Rousseau, E. Doris, Tetrahedron Lett. 2002, 43, 2013-2015.

Walk this way! A walker unit is able to walk in either direction along a four‐foothold molecular track, depending on the sequence of application of four external stimuli: acid, base, UV light, and visible light in the presence of iodine (see picture). The isomerization of the stilbene moiety in the molecular track is key for the achievement of directional transport through a Brownian ratchet mechanism.

We report a new family of hexa‐peri‐hexabenzocoronene (HBC)‐based helical nanographenes incorporating π‐extended carbo[5]helicenes bearing an octagonal carbocycle. This family represents a new kind of highly distorted saddle‐helix hybrid nanographenes. For the first time, the eight‐membered ring becomes a constituent of both a carbo[5]helicene and a HBC and thus, the negative curvature is responsible for twisting both units. This novel chiral motif, namely, oct‐[5]helicene results in the largest torsion angle recorded so far for a carbo[5]helicene (θ=79.5°), as it has been suggested by DFT‐calculations and confirmed by X‐ray crystallography. Consequently, the barriers of isomerization become exceptionally high for a [5]helicene unsubstituted in the fjord region since neither racemization nor decomposition were observed at 200 °C for 1 or 3 during 5 h. Therefore, racemic resolutions allowed subsequent chiroptical studies showing the ECD and CPL responses of this novel family of chiral nanographenes.