Achieving enantiomer resolution in chiral carbaporphyrins is often hindered by conformational lability. We report herein a 1,5-naphthiporphyrin (1) composed of three 1,5-naphthalene units bridged by dipyrromethene linkers that exhibits inherent chirality but racemizes through inversion of the curvature. Upon metalation with Rh(I), a trinuclear complex (1-Rh3) forms that restricts naphthalene rotation, suppresses enantiomer interconversion, and enables chromatographic resolution on a chiral stationary phase. The resolved enantiomers display significant chiroptical responses with high absorption dissymmetry factors up to 0.038 at 654 nm. Importantly, the metal centers define the accessible stereochemical manifold and the chiroptical output, while the same ligand architecture programs the assembly of a heteropolynuclear Zn4Na cluster, explicitly positioning this work within coordination strategies for stereocontrol and multinuclear construction.
Zhang et al. (Tue,) studied this question.