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What prompted you to investigate this topic/problem? Small organic CPL-active molecules (CPL-SOMs) have attracted considerable attention in the last decade for their potential application in next-generation optical devices. Our group is investigating CPL-SOMs with chiral Schiff-base ligands, and recently reported that boron difluoride complexes exhibit efficient and tunable CPL properties. [1,2] These findings prompted us to clarify two questions: (1) How do the molecular structures affect the CPL properties; (2) How does molecular alignment affect their CPL properties. The second of these questions is discussed in this work.

The syntheses, structures, and circularly polarized luminescence (CPL) properties of bis(boron difluoride) complexes with chiral Schiff‐base ligands are described herein. A series of chiral Schiff‐base bis(boron difluoride) complexes based on the naphthalene backbone were prepared by reacting BF3⋅OEt2 with the corresponding precursors, and the molecular structures were identified by NMR spectroscopy and X‐ray diffraction (XRD) analysis. These complexes exhibited efficient photoluminescence in dilute solution with high emission quantum yields (Φ) up to 0.99. The circularly polarized luminescence properties of the molecules were also investigated. Compared to solution, in the KBr dispersed pellet state the absolute value of the luminescence dissymmetry factor (glum) was significantly increased up to 1.2×10−2. The photophysical properties were further investigated by means of DFT calculations.