Conformationally Imprinted Receptors:  Atropisomers with “Write”, “Save”, and “Erase” Recognition Properties

Degenhardt, Charles F.; Lavin, Judith Maria; Smith, Mark D.; Shimizu, Ken D.

doi:10.1021/ol051325t

Cited by 39 publications

(25 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Restricted rotation has been reported for N-phenyl imide derivatives with ortho-substituents other than hydrogen. [73][74][75][76][77][78][79][80][81][82][83]94 As the size of this substituent increases, the energy barrier to rotation increases due to steric repulsion with the oxygen atom of the imide. [84][85][86] In addition, the angle between the substituted phenyl and imide rings increases towards perpendicular to minimise this steric interaction.…”

Section: 356-tetramethylphenyl Diimide As the Linkermentioning

confidence: 99%

Molecular tweezers with a rotationally restricted linker and freely rotating porphyrin moieties

et al. 2018

View full text Add to dashboard Cite

The effect of the degree of conformational rigidity and/or flexibility on preorganisation in artificial molecular receptors continues to be actively explored by supramolecular chemists. This work describes a bis-porphyrin architecture, linked via a rigid polycyclic backbone, in which a sterically bulky 2,3,5,6-tetramethylphenyl diimide core restricts rotation to afford two non-interconvertible tweezer conformations; syn- and anti-. After separation, the host-guest chemistry of each conformation was studied independently. The difference in host geometry allows only the syn-conformation to form a strong 1 : 1 bis-porphyrin complex with the diamino ligand 1,4-diazabicyclo[2.2.2]octane (DABCO) (K11 = 1.25 × 108 M-1), with the anti-conformation adopting a 2 : 2 sandwich complex with DABCO (K22 = 5.57 × 1017 M-3).

show abstract

Section: 356-tetramethylphenyl Diimide As the Linkermentioning

confidence: 99%

Molecular tweezers with a rotationally restricted linker and freely rotating porphyrin moieties

et al. 2018

View full text Add to dashboard Cite

show abstract

“…Indeed, perylene bisimides and similar imide compounds that exhibit restricted rotation around CÀN imide bond with considerably high rotational barriers have been reported previously. [24,28] Thus, such rotational isomers can be frozen at low temperature. For PBI 15 we have observed two doublets at d = 8.68 and 8.64 ppm for the two perylene ortho-protons P4/P4' at low temperature (274 K) in [D 8 ]THF, whereas for the other two ortho-protons (P1) only one doublet at d = 8.71 ppm was observed.…”

Section: Solvent-dependent Folding Properties In the Ground Statementioning

confidence: 99%

Phenylene Ethynylene‐Tethered Perylene Bisimide Folda‐Dimer and Folda‐Trimer: Investigations on Folding Features in Ground and Excited States

Fimmel

Son

Sung

et al. 2014

Chemistry A European J

View full text Add to dashboard Cite

In this work, we have elucidated in detail the folding properties of two perylene bisimide (PBI) foldamers composed of two and three PBI units, respectively, attached to a phenylene ethynylene backbone. The folding behaviors of these new PBI folda-dimer and trimer have been studied by solvent-dependent UV/Vis absorption and 1D and 2D NMR spectroscopy, revealing facile folding of both systems in tetrahydrofuran (THF). In CHCl3 the dimer exists in extended (unfolded) conformation, whereas partially folded conformations are observed in the trimer. Temperature-dependent (1) H NMR spectroscopic studies in [D8 ]THF revealed intramolecular dynamic processes for both PBI foldamers due to, on the one hand, hindered rotation around CN imide bonds and, on the other hand, backbone flapping; the latter process being energetically more demanding as it was observed only at elevated temperature. The structural features of folded conformations of the dimer and trimer have been elucidated by different 2D-NMR spectroscopy (e.g., ROESY and DOSY) in [D8 ]THF. The energetics of folding processes for the PBI dimer and trimer have been assessed by calculations applying various methods, particularly the semiempirical PM6-DH2 and the more sophisticated B97D approach, in which relevant dispersion corrections are included. These calculations corroborate the results of NMR spectroscopic studies. Folding features in the excited states of these PBI foldamers have been characterized by using time-resolved fluorescence and transient absorption spectroscopy in THF and CHCl3 , exhibiting similar solvent-dependent behavior as observed for the ground state. Interestingly, photoinduced electron transfer (PET) process from electron-donating backbone to electron-deficient PBI core for extended, but not for folded, conformations was observed, which can be explained by a fast relaxation of excited PBI stacks in the folded conformation into fluorescent excimer states.

show abstract

“…In addition, the analysis of balance 1 is facilitated by the room temperature stability of the syn and anti isomers. [46][47][48][49] In solution, the kinetic stability of the isomers enabled rapid and accurate measurement of the anti/syn ratios by integrating the 1 H NMR spectra as the isomers were in slow exchange. Balance 1 could also be equilibrated in one solvent, and then the anti/syn ratio measured in another.…”

Section: Introductionmentioning

confidence: 99%

A High‐Barrier Molecular Balance for Studying Face‐to‐Face Arene–Arene Interactions in the Solid State and in Solution

Chong

Carroll

Burns

et al. 2009

Chemistry A European J

View full text Add to dashboard Cite

An atropisomeric molecular balance was developed to study face-to-face arene-arene interactions. The balance has a large central 1,4,5,8-naphthalene diimide surface that forms intramolecular arene-arene interactions with two pendent arms. The balance adopts distinct syn and anti isomers with varying numbers of intramolecular interactions. Thus, the strength of the arene-arene interaction could be quantitatively measured by NMR spectroscopy from the anti/syn ratios. The size of the arene arms was easily varied, which allowed examination of the relationship between arene size and strength of the interaction. A nonlinear size dependence was observed in solution with larger arene arms having a disproportionately stronger arene-arene interaction. The intramolecular arene-arene interactions were also characterized in the solid state by X-ray crystallography. These studies were facilitated by the kinetic stability of the syn and anti isomers at room temperature due to the high isomerization barrier (DeltaG=27.0 kcal mol(-1)). Thus, the anti isomer could be selectively isolated and crystallized in its folded conformation. The X-ray structures confirmed that the anti isomers formed two strong intramolecular arene-arene interactions with face-to-face geometries. The solid-state structure analysis also reveals that the rigid framework may contribute to the observed nonlinear size trend. The acetate linker is slightly too long, which selectively destabilizes the balances with smaller arene arms. The larger arene arms are able to compensate for the longer linker and form effective intramolecular arene-arene interactions.

show abstract

Conformationally Imprinted Receptors: Atropisomers with “Write”, “Save”, and “Erase” Recognition Properties

Cited by 39 publications

References 12 publications

Molecular tweezers with a rotationally restricted linker and freely rotating porphyrin moieties

Molecular tweezers with a rotationally restricted linker and freely rotating porphyrin moieties

Phenylene Ethynylene‐Tethered Perylene Bisimide Folda‐Dimer and Folda‐Trimer: Investigations on Folding Features in Ground and Excited States

A High‐Barrier Molecular Balance for Studying Face‐to‐Face Arene–Arene Interactions in the Solid State and in Solution

Contact Info

Product

Resources

About