Ridge-Tile-like Chiral Topology: Synthesis, Resolution, and Complete Chiroptical Characterization of Enantiomers of Edge-Sharing Binuclear Square Planar Complexes of Ni(II) Bearing Achiral Ligands

摘要

Binuclear square planar Ni(II) complexes are described, formed by two tridentate ligands with two imine-nitrogens coordinating two nickel atoms. Such complexes are synthetically readily available with great structural variety and present new types of ridge-tile-like chiral compounds that are reasonably stable in the appropriate "bent" conformation. Enantiomerically pure samples of these compounds have been obtained for the first time using HPLC with a chiral stationary phase. Absolute configurations and chiroptical properties are fully characterized by ECD, VCD, ORD spectroscopy, and theoretical calculations. These new compounds with ridge-tile-like chiral topology are configurationally reasonably stable [ΔG* = 121.4 kJ mol~(-1), t_(1/2) = 14.9 h (78℃, ethanol)], and therefore their chemistry, physical properties, and applications can be systematically studied.