Temperature‐Dependent Left‐ and Right‐Twisted Conformational Changes in 1 : 1 Host‐Guest Systems: Theoretical Modeling and Chiroptical Simulations

Abstract An efficient strategy for high‐performance chiral materials is to design and synthesize host molecules with left‐ and right‐ ( M ‐ and P ‐)twisted conformations and to control their twisted conformations. For this, a quantitative analysis is required to describe the chiroptical inversion, chiral transfer, and chiral recognition in the host‐guest systems, which is generally performed using circular dichroism (CD) and/or proton nuclear magnetic resonance ( 1 H NMR) spectroscopies. However, the mass‐balance model that considers the M ‐ and P ‐twisted conformations has not yet been established. In this study, we derived the novel equations based on the mass‐balance model for the 1 : 1 host‐guest systems. Then, we further applied them to analyze the 1 : 1 host‐guest systems for the achiral calixarene‐based capsule molecule, achiral dimeric zinc porphyrin tweezer molecule, and chiral pillar[5]arene with the chiral and/or achiral guest molecules by using the data obtained from the CD titration, variable temperature CD (VT−CD), and 1 H NMR experiments. The thermodynamic parameters (Δ H and Δ S ), equilibrium constants ( K ), and molar CD (Δ ϵ ) in the 1 : 1 host‐guest systems could be successfully determined by the theoretical analyses using the derived equations.