Solvent‐Directed Handedness in a Chirally Twisted Tetrakisporphyrin Macrocycle

A chirally twisted tetrakisporphyrin macrocycle was synthesized by incorporating a chiral dioxolane into a tetrakisporphyrin macrocycle. The solvent type influenced the preferred handedness of the twisted conformation. Circular dichroism measurements and computational analyses determined the handedness of the conformers in solvents toluene and dimethylformamide.

Abstract

A chirally twisted tetrakisporphyrin macrocycle was synthesized by incorporating a chiral dioxolane linker as a chiral unit into a tetrakisporphyrin macrocycle. Circular dichroism measurements and computational analyses confirmed that the solvents influence the handedness of the twisted macrocycle. The tetrakisporphyrin macrocycle is prone to adopt the chirally twisted conformations that allow efficient solvation depending on both the polarity and structure of the solvent molecules. Specifically, nonpolar aromatic solvents promote the (M)-twisted conformer of the (R,R)-tetrakisporphyrin macrocycle, whereas polar aromatic and halogenated solvents stabilize the (P)-twisted conformer. In high-polar solvents, the structures of the solvent molecules most likely determine the preference of the (P)- and (M)-twisted conformers.

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