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The development of new chiral building blocks for constructing complex chiral architectures, such as macrocycles and cages, is both crucial and challenging. Although concave-shaped calixarenes have been established as versatile building blocks for the synthesis of cage compounds, there are no reports on cages constructed from chiral calix4arene derivatives. Herein, we present a straightforward and effective method for gram-scale synthesis of a new member of chiral calix4arene macrocycle enantiomers, namely, phenol4arene (PC4A). As a proof of concept, we functionalized these enantiomers into tetraformylphenol4arene (PC4ACHO) derivatives via the Duff reaction to construct chiral porous organic cages (CPOCs) using polyamine synthons. Specifically, we employ two fluorescent amine synthons, bis(4-aminophenyl)phenylamine and tris(4-aminophenyl)amine, to assemble with PC4ACHO enantiomers, resulting in 2 + 4 lantern-shaped and 6 + 8 truncated octahedral CPOCs, respectively. These structures have been unambiguously characterized by single-crystal X-ray diffraction and circular dichroism (CD) spectroscopy. Notably, the 6 + 8 truncated CPOCs exhibit internal diameters of approximately 3.1 nm, a cavity volume of around 5300 Å 3, and high specific surface areas of up to 1300 m 2 g –1 after desolvation, making them among the largest CPOCs reported. Additionally, investigations into their chiral sensing performance demonstrate that these PC4A-based CPOCs enable the enantioselective recognition of amino acids and their derivatives. This work strongly suggests that PC4A can serve as an excellent building block for the rational design of chiral materials with practical applications.
Qiu et al. (Mon,) studied this question.