Chiral Recognition Of Monoamines Bym-Phthalic Diamide-linked Zinc Bisporphyrinates And Ester-linked Trisporphyrinate

Porphyrins and their metal compounds are widely used in various fields because of their unique chemical properties.Due to the characteristic absorption in the Soret band,porphyrin systems are widely used in chiral recognition.Porphyrins can be used to recognize the absolute configurations of various chiral guest.But it is more difficult to recognize those of chiral monoamines,which remains a challenging task.In this thesis,we synthesized three new m-phthalic diamide-linked bisporphyrins and an ester-linked trisporphyrin.The chiral recognition abilities of their metallic complexes to chiral monoamines have been examined.In the first part,four new m-phthalic diamide-linked bisporphyrinates have been synthesized:[Zn2-?],[Zn2-?],[Zn2-?] and [Zi Ni-?].We studied the chirality transfer from chiral monoamines to these hosts by CD spectra.We also investigated the chirality transfer mechanism for [Zn2-?].The NMR studies suggest there are two different carbonyl groups which are involving both intramolecular and intermolecular Zn-O bonds.When the host interacts with the guest,it will stepwisely forms 1:1 and 1:2 host-guest complexes.During our studies,the crystal structures of a 1:1 complexes between zinc bisporphyrinate and a chiral monoamine were firstly reported.The structures reveal that there is an intramolecular hydrogen bond between the amide oxygen and the coordinated NH2.We did further investigation on the chirality transfer mechanism by DFT computation.Our studies suggest the interactions between the linker and guests in this bisporphyrin system are crucial in the chirality transfer process,and the nature of the bulkiest substituent of chiral monoamines makes a difference.For R-type of guests,when it is an alkyl group,the steric repulsion makes the conformer A more energetically favorable,which leads to the anticlockwise twist and negative Cotton effect;when it is an aryl group,the p-p interaction makes the conformer B more energetically favorable,which leads to the clockwise twist and positive Cotton effect.The second part is related to the ester group-linked trisporphyrinate [Zn3-?].This trisporphyrinate has also a good recognition ability to chiral monoamines.By comparison with the amide-linked trisporphyrinate,the change of the linker can also adjust its chiral recognition ability.In this study,we obtained the crystal structure of [Zn3-?],which reveals that there are intramolecular Zn-O bonds within the triporphyrinate.Since we have not got a suitable single crystal of the host-guest complex,the related work is still under investigation.