Transfer and Amplification of Chirality Within the “Ring of Fire” Observed in Resonance Raman Optical Activity Experiments

We report extremely strong chirality transfer from a chiral nickel complex to solvent molecules detected as Raman optical activity (ROA). Electronic energies of the complex were in resonance with the excitation‐laser light. The phenomenon was observed for a wide range of achiral and chiral solvents. For chiral 2‐butanol, the induced ROA was even stronger than the natural one. The observations were related to so‐called quantum (molecular) plasmons that enable a strong chiral Rayleigh scattering of the resonating complex. According to a model presented here, the maximal induced ROA intensity occurs at a certain distance from the solute, in a three‐dimensional “ring of fire”, even after rotational averaging. Most experimental ROA signs and relative intensities could be reproduced. The effect might significantly increase the potential of ROA spectroscopy in bioimaging and sensitive detection of chiral molecules.     

A Nontrigonal Tricoordinate Phosphorus Ligand Exhibiting Reversible “Nonspectator” L/X‐Switching

We report here a “nonspectator” behavior for an unsupported L ‐function σ³‐P ligand (i.e. P{N[o‐NMe‐C₆H₄]₂}, 1a ) in complex with the cyclopentadienyliron dicarbonyl cation (Fp⁺). Treatment of 1a ?Fp⁺ with [(Me₂N)₃S][Me₃SiF₂] results in fluoride addition to the P‐center, giving the isolable crystalline fluorometallophosphorane 1a^F ?Fp that allows a crystallographic assessment of the variance in the Fe?P bond as a function of P‐coordination number. The nonspectator reactivity of 1a ?Fp⁺ is rationalized on the basis of electronic structure arguments and by comparison to trigonal analogue (Me₂N)₃P?Fp⁺ (i.e. 1b ?Fp⁺), which is inert to fluoride addition. These observations establish a nonspectator L/X‐switching in (σ³‐P)–M complexes by reversible access to higher‐coordinate phosphorus ligand fragments.     

“Inherently Chiral” Ionic‐Liquid Media: Effective Chiral Electroanalysis on Achiral Electrodes

To achieve enantioselective electroanalysis either chiral electrodes or chiral media are needed. High enantiodiscrimination properties can be granted by the “inherent chirality” strategy of developing molecular materials in which the stereogenic element responsible for chirality coincides with the molecular portion responsible for their specific properties, an approach recently yielding outstanding performances as electrode surfaces. Inherently chiral ionic liquids (ICILs) have now been prepared starting from atropisomeric 3,3′‐bicollidine, synthesized from inexpensive reagents, resolved into antipodes without need of chiral HPLC and converted into long‐chain dialkyl salts with melting points below room temperature. Both the new ICILs and shorter family terms, solid at room temperature, employed as low‐concentration additives in achiral ILs, afford impressive enantioselection for the enantiomers of different probes on achiral electrodes, regularly increasing with additive concentration.