The characterization of the stability of self-assembled supramolecular systems is critical for numerous applications that rely on non-covalent interactions between the components.However,in phthalocyanines(Pcs),the co...The characterization of the stability of self-assembled supramolecular systems is critical for numerous applications that rely on non-covalent interactions between the components.However,in phthalocyanines(Pcs),the coordination of ligands to the central metal is typically not accompanied by significant spectral changes,complicating the determination of association constants(K_(1)).展开更多
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...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 vip.This work demonstrates the utility of 1,1’-binapthyllinked chiral hosts for chiral analysis of ditopically interacting enantiomers.展开更多
Molecular rotors are an important class of dynamic molecules which have been studied not only for their possible uses as components of molecular machines but also because of potential applications as probes of local v...Molecular rotors are an important class of dynamic molecules which have been studied not only for their possible uses as components of molecular machines but also because of potential applications as probes of local viscosity in biological media,especially self-assembled membranes.For the former,factors affecting rotational motility are critical while for the latter the rotor activity must be complexed with an output signal(often fluorescence)for reporting of local conditions.Molecular single stator-double rotor activity of an oxidized resorcinarene(fuchsonarene)macrocycle containing unsaturated hemiquinonoid groups at its meso positions was investigated.Fuchsonarenes contain two hemiquinonoid substituents at diagonally-opposed meso-positions with two electron rich phenol groups at the remaining meso-positions between the hemiquinonoid groups.All meso-substituents are in proximity at one side of the resorcinarene macrocycle(so-called rccc-type isomer)with rotational activity of the phenol meso-substituents.Rotation rates of the phenol moieties can be controlled by varying temperature,solvent polarity and acidity of the medium of study with rotation being thermally activated in neutral and acidic media and tunable in the range from 2 s^(−1) to 20000 s^(−1).Experimental and computational data indicate that rotation of the mobile phenol meso-substituents is remotely affected by interactions with acidic solvents at the carbonyl CvO groups of macrocyclic acetyloxy groups,which occurs with the emergence of a lower energy electronic absorption band whose intensity is correlated with both the acidity of the medium and the rotation rate of the phenol substituents.Time-dependent DFT calculations suggest that the low energy band is due to a molecular conformational adjustment affecting electronic conjugation caused by strong interaction of macrocyclic acetyloxy carbonyl groups with the acid medium.The work presents a molecular mechanical model for estimating solution acidity and also gives insight into a possible method for modulating rotor activity in molecular machines.展开更多
基金supported by the Czech Science Foundation(23-06177S)the project New Technologies for Translational Research in Pharmaceutical Sciences/NETPHARM,project ID CZ.02.01.01/00/22_008/0004607,co-funded by the European Union.VN,MM and JD would also like to acknowledge financial support from the Ministry of Education,Youth and Sports(ERC CZ programme,LL2318)This work was also supported by the World Premier International Research Center Initiative(WPI Initiative),MEXT,Japan.Financial support from Charles University(SVV 260666)is gratefully acknowledged as well.
文摘The characterization of the stability of self-assembled supramolecular systems is critical for numerous applications that rely on non-covalent interactions between the components.However,in phthalocyanines(Pcs),the coordination of ligands to the central metal is typically not accompanied by significant spectral changes,complicating the determination of association constants(K_(1)).
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.JPMJCR1665partly financially supported by the National Science Foundation(Grant No.1401188 to FD).
文摘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 vip.This work demonstrates the utility of 1,1’-binapthyllinked chiral hosts for chiral analysis of ditopically interacting enantiomers.
基金supported by JSPS KAKENHI Grant No.19K05229Computational resources were supplied by the project“e-Infrastruktura CZ”(e-INFRA LM2018140)provided within the program Projects of Large Research,Development and Innovations Infrastructures.
文摘Molecular rotors are an important class of dynamic molecules which have been studied not only for their possible uses as components of molecular machines but also because of potential applications as probes of local viscosity in biological media,especially self-assembled membranes.For the former,factors affecting rotational motility are critical while for the latter the rotor activity must be complexed with an output signal(often fluorescence)for reporting of local conditions.Molecular single stator-double rotor activity of an oxidized resorcinarene(fuchsonarene)macrocycle containing unsaturated hemiquinonoid groups at its meso positions was investigated.Fuchsonarenes contain two hemiquinonoid substituents at diagonally-opposed meso-positions with two electron rich phenol groups at the remaining meso-positions between the hemiquinonoid groups.All meso-substituents are in proximity at one side of the resorcinarene macrocycle(so-called rccc-type isomer)with rotational activity of the phenol meso-substituents.Rotation rates of the phenol moieties can be controlled by varying temperature,solvent polarity and acidity of the medium of study with rotation being thermally activated in neutral and acidic media and tunable in the range from 2 s^(−1) to 20000 s^(−1).Experimental and computational data indicate that rotation of the mobile phenol meso-substituents is remotely affected by interactions with acidic solvents at the carbonyl CvO groups of macrocyclic acetyloxy groups,which occurs with the emergence of a lower energy electronic absorption band whose intensity is correlated with both the acidity of the medium and the rotation rate of the phenol substituents.Time-dependent DFT calculations suggest that the low energy band is due to a molecular conformational adjustment affecting electronic conjugation caused by strong interaction of macrocyclic acetyloxy carbonyl groups with the acid medium.The work presents a molecular mechanical model for estimating solution acidity and also gives insight into a possible method for modulating rotor activity in molecular machines.
