| Chiral recognition is one kind of important molecular recognition insupramolecular chemistry. We have designed and synthesized a series of rigidamide-linked zinc(II) bisporphyrinates. Using them as hosts, we have studied theirchiral recognition abilities for chiral guests by circular dichroism spectra, X-raycrystallography, UV-Vis titration,1H NMR and DFT/TDDFT. The correspondingmechanism has also been probed.In this thesis, we have designed and synthesized four bisporphyrinates containingdouble amide groups on the basis of mono o-aminophenyl substituted porphyrin,N,N′-Bis[5-(o-phenyl)-10,15,20-triphenylporphyrinato-yl)]oxalic amide zinc(II)(compound2), N,N′-Bis[5-(o-phenyl)-10,15,20-triphenylporphyrinato-yl)] p-phthalicamide zinc(II)(compound3), N,N′-Bis[5-(o-phenyl)-10,15,20-triphenylporphyrinato-yl)] m-phthalic amide zinc(II)(compound4) and N,N′-Bis[5-(o-phenyl)-10,15,20-triphenylporphyrinato-yl)] o-phthalic amide zinc(II)(compound5). We have studiedtheir chiral recognition abilities for D/L-alanine ethyl ester, D/L-vlaine ethyl ester,D/L-leucine ethyl ester, D/L-phenylalanine ethyl ester, D/L-phenylglycine ethyl ester.Compound2,3and4have exhibited strong chiral recognition abilities for amino acidesters.1. Using compound2as a host, we have studied its chiral recognition ability forfive amino acid esters. The ICD spectra showed the positive exciton chirality forL-amino acid esters and negative exciton chirality for D-amino acid esters in Soret band.Using5-(2-(methyl-N-oxamate)-phenyl)-10,15,20-triphenyl-porphyrin Zinc(II)(compo--und1) and tetraphenylporphyrin Zinc(II)([Zn(TPP)]） as reference compounds, wehave studied the role of hydrogen bonds in the chiral recognition process by the UV-Vistitration. We have further investigated the hydrogen bonding interactions between theporphyrin host and amino acid ester by X-ray crystallography and1H NMR. We havealso done DFT/TDDFT calculations between compound2and L-Phe-OEt, which provide the optimized structure of the host-guest complex. The calculated CD signal isconsistent with the experiment result. The origination of CD signal has been explainedthrough molecular orbital transitions.2. Using compound3,4and5as hosts, we have studied their chiral recognitionability for five amino acid esters. The ICD spectra of complexes formed betweencompound3/4and amino acid esters showed the negative exciton chirality for L-aminoacid esters and positive exciton chirality for D-amino acid esters in Soret band.However, there was no observable CD signal in the case of compound5. We havefurther investigated the interactions between the compound3/4and amino acid ester byX-ray crystallography and UV-Vis titration. The corresponding chiral recognitionmechanism has also been probed. |
