Chirality Sensing of Chiral Carboxylic Acids by a Ureido-Linked Zinc Bisporphyrinate

We designed and synthesized a ureido-linked zinc bisporphyrinate [Zn2(UBis)]. CD spectra show that this zinc bisporphyrinate has the ability to sense the chirality of chiral carboxylic acids without derivatization. Our studies suggest that the phenyl ring in the linker forms pi-pi interactions with porphyrin planes and that the carboxylic acid is coordinated to the zinc in the host-guest complex. DFT calculations show that the bisporphyrin adopts a "Z"-shaped configuration, and that the ureido group forms hydrogen bonds with carboxylic acids. The combination of pi-pi interactions, coordination interactions and hydrogen bonding interactions leads to the chirality sensing ability of [Zn2(UBis)]. A zinc bisporphyrinate containing ureido groups in the linker has been designed and synthesized, and demonstrated to have the ability to sense the chirality of chiral carboxylic acids without derivatization. Our studies suggest that pi-pi interactions, coordination interactions and hydrogen bonding interactions are involved in the chirality sensing process. image