摘要
Chiral 1,1’-binaphthyl-linked diporphyrin‘tweezers’(R)-1/(S)-1 and the corresponding zinc(II)complexes(R)-2/(S)-2 were prepared as chiral host molecules,and their utility for chiral analyses(especially enantiomeric excess(ee)determinations)were evaluated.Tris(1-n-dodecyl)porphyrins were used for the first time as the interacting units.Host capabilities of the diporphyrin tweezers were investigated by titrations with(R,R)-and(S,S)-cyclohexane-1,2-diamine(CHDA).The host molecules could be used as multichannel probes of ee by using UVvis,circular dichroism(CD),fluorescence emission and 1H nuclear magnetic resonance(1 H-NMR)methods.Chiral configurations could also be differentiated using CD or 1HNMR spectroscopy.All three optical techniques give good resolution of ee with reasonable sensitivity considering the low concentrations used(ca.10^-6 mol·L^-1).The ee determination of CHDA enantiomers using NMR spectroscopy is also possible because of the reasonably well separated resonances in the case of(R,R)-and(S,S)-CHDA.Non-metallated(R)-1/(S)-1 hosts could not be used to detect chiral information in a strongly acidic chiral guest.This work demonstrates the utility of 1,1’-binapthyllinked chiral hosts for chiral analysis of ditopically interacting enantiomers.
基金
partly supported by World Premier International Research Center Initiative,MEXT,Japan.The authors are grateful to Japan Society for the Promotion of Science(JSPS)for a JSPS Fellowship(to D.T.P.)
partially supported by JSPS KAKENHI(Coordination Asymmetry)Grant No.JP16H06518,JSPS KAKENHI Grant No.19K05229 and CREST,JST Grant No.JPMJCR1665
partly financially supported by the National Science Foundation(Grant No.1401188 to FD).
