Synthesis Of Novel Amide-linked Bisporphyrins And Their Applications In Chiral Recognition Of Amino Acid Esters

Chiral recognization is one kind of important molecular recognition insupramolecular chemistry. Many biomolecules are chiral molecules, such as aminoacids, polysaccharides, polypeptides and proteins. Many chemical reactions inbiological process are related to chiral recognization, so the recognization of chiralmolecules, such as amino acid derivatives, is crucial to supramolecular chemistry. Anappropriate porphyrin host can interact with amino acid deravitates throughcoordination interactions, hydrogen bonding interactions and sterical interaction etc.Because amide group can be a good candicate as an acceptor and a donor ofhydrogen bond, it plays a key role in biorecognization and sensor. In this thesis, wehave designed and synthesized a bisporphyrin contains double amide groups based onmono o-aminophenyl substituted porphyrin, N,N′-Bis[5-(o-phenyl)-10,15,20-triphenylporphyrinato-yl)zinc]oxalic amide. With this zinc porphyrinate as a host, wehave studied its chiral recognition ability to amnio acid esters. CD spectra showed thatin all complexes with L-amino acid esters the longer-wavelength peak of the Soret bandwas positive and the shorter-wavelength peak was negative. While the complexes withD-amino acid ester showed similar signal with opposite sign. We have furtherinvestigated the interaction between the porphyrin host and amino acid ester by UV-visspectra and~1H NMR. We have also done DFT calculations, which provide theoptimized structure of the host-guest compolex. The calculated CD signal is consistentwith the experiment result. The origination of CD signal has been explained throughmolecular orbital transitions. Besides, the crystal structure of (D-Phe-OEt)-(L-Phe-OEt)-N,N′-Bis[5-(o-phenyl)-10,15,20-triphenylporphyrinato-yl)zinc]oxalic amide has beensolved, which further reveal the existence of one special hydrogen bond in the host-guest complex. Our study has established a solid fundation for the chrialrecognition of biological molecules by such bisporphyrin system.