Chiral Co₃Y Propeller-Shaped Chemosensory Platforms Based on¹⁹F-NMR

Abstract

Two propeller-shaped chiral CoIII 3YIII complexes built from fluorinated ligands are synthesized and characterized by single-crystal X-ray diffraction (SXRD), IR, UV–vis, circular dichroism (CD), elemental analysis, thermogravimetric analysis (TGA), electron spray ionization mass spectroscopy (ESI-MS), and NMR (1H, 13C, and 19F). This work explores the sensing and discrimination abilities of these complexes, thus providing an innovative sensing method using a 19F NMR chemosensory system and opening new directions in 3d/4f chemistry. Control experiments and theoretical studies shed light on the sensing mechanism, while the scope and limitations of this method are discussed and presented.

Chemical Chartographisis: a contemporary perspective in molecular design and synthesis

“…Following these results and given our excellent understanding of 3d/4f dynamic systems, we thought that the introduction of several F-antenna into a propeller-shaped bimetallic molecule, [57][58][59] and synthesis of the F-Co III 3 Y III analogue, would represent an ideal platform for amine sensing. 60 Our hypothesis was based on the following points: (a) the high ionic radii of 4f ions make it difficult to control ligand exchange with solvent-substrates. (b) Amines are known to coordinate to lanthanide metal centres in organic media; 61,62 (c) the usual coordination geometry of the Co centres is realised, and the 4f ion is captured in a trigonal antiprism, which limits access to solvent-substrate molecules via only axial sites, thus replicating the coordination sphere of the non-labile Pd and Ru analogues.…”