Chiroptical Recognition of Carboxylates with Charge‐Neutral Double‐Stranded Zinc(II) Helicates

Abstract

Chirality analysis of small molecules for the determination of their enantiopurity is nowadays ruled by streamlined chromatographic methods which utilize chiral stationary phases. Chiroptical probes which rely on host‐guest interactions are so far overshadowed by the latter but have the benefit of depending only on common spectroscopic techniques such as CD spectroscopy to distinguish enantiomers and to quantify their ratio. Interest into this receptor‐based approach is constantly rising because non‐invasive high‐throughput screenings with a minimal waste production can be performed. In this study we investigate the possibility to utilize metal‐based containers in form of charge‐neutral helicates able to recognize anions for this purpose. Key building block of the helicates are triazole units which show rotational freedom and give rise to either a meso‐structure or a racemic mixture of the right‐ and left‐handed complex. A chiroptical response of the probe is observed upon recognition of chiral mono‐ or dicarboxylates and chirality analysis of tartrate is conducted by CD spectroscopy.

Exploiting Chirality in Confined Nanospaces

“…This feature has been studied to obtain system owning enhanced Circular Dichroism (CD) and/or Circularly Polarized Luminescence (CPL). [7,45] While CD properties have been extensively studied in sensing, [46][47][48] which will be described in the next paragraph, CPL has recently attracted the attention due to the capability of CSC to: induce chromophores cooperative effects, prevent aggregation phenomena, finely tune their distance either by design or by the use of different guests, and to have mixed interacting chromophores. [45,49] Initial examples have been directed to the emissive properties of lanthanide-based CSC.…”