Chiral slipped 5,8:9′,10′-cyclodimers were preferentially produced over classical 9,10:9′,10′-cyclodimers upon supramolecular photocyclodimerization of 2-anthracenecarboxylate (AC) mediated by β-cyclodextrin (β-CD). This photochirogenic route to the cyclodimers, exclusively head-to-tail (HT) and highly enantioselective, has long been overlooked in foregoing studies but is dominant reality absolutely supramolecularly activated 2:2 complexation AC with β-CD. The intricate structural...

Photoirradiation at λ > 320 nm of 2-anthracenecarboxylate bound to human serum albumin in an aqueous buffer solution 5 °C gave syn head-to-tail cyclodimer 2 82% ee and anti head-to-head 3 90% ee.

In the supramolecular photocyclodimerization of 2-anthracenecarboxylate mediated by 6A,6D-diguanidino-γ-cyclodextrin (CD), chiral sense and enantiomeric excess photoproduct were dynamic functions temperature cosolvent to afford (M)-anti head-to-head cyclodimer in 64% ee aqueous methanol at −70 °C but antipodal (P)-isomer 86% ammonia −85 °C, while corresponding diamino-γ-CD host did not show such unusual photochirogenic behaviors. The landscape was very steep against sign-inverted content...

The (P)- and (M)-3-azonia[6]helicenyl β-cyclodextrins exhibit L/D selectivities of up to 12.4 P/M preferences 28.2 upon complexation with underivatized proteinogenic amino acids in aqueous solution at pH 7.3.

Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxyalate (AC) was performed at 25 °C in aqueous buffer solution (pH 7) the presence bovine-serum albumin (BSA) to afford four [4 + 4] cyclodimers, i.e., anti- and syn-head-to-tail (HT) (1 2) syn-head-to-head (HH) dimers (3 4), which only 2 3 are chiral. We found that (1) BSA possesses sets binding sites for AC different affinities, stoichiometries, chiral environment photoreaction, bind 1, 3, 2, molecules with constants 5.3 ×...

The mechanism for the high enantiomeric excess (ee) (80-90%) observed in photocyclodimerization of 2-anthracenecarboxylate (AC) chiral binding sites human serum albumin (HSA) was studied using fluorescence anisotropy. A long rotational correlation time 36 ns excited states ACs bound to HSA site responsible ee, suggesting that have restricted mobility this site. same prochiral face protected by protein, and protection is ee observed. These insights provide a strategy rational design...

Photophysics and photochemistry of 2-anthracenecarboxylate (AC) bound to bovine serum albumin (BSA) were investigated in detail for the first time by electronic absorption, circular dichroism (CD), steady-state time-resolved fluorescence, fluorescence quenching, product analysis studies. Through spectroscopic investigations, it was revealed that four independent binding pockets BSA, which are known accommodate 1, 3, 2, 3 AC molecules order decreasing affinity, distinctly different...

Pyromellitate-bridged cyclodextrin nanosponges (CDNSs) evolved from sol into gel state upon gradual increase of the concentration 0.2 to 2000 mg mL−1 in water. The enantiodifferentiating geometrical photoisomerizations (Z)-cyclooctene and (Z,Z)-1,3-cyclooctadiene sensitized by CDNS at various concentrations were critically affected phase transition afford corresponding (E)- (E,Z)-isomers highest enantiomeric excesses state.

The photochirogenesis of 2-anthracenecarboxylic acid (AC) complexed to a hydrogen-bonding template (TKS159) was investigated obtain mechanistic information on how chirogenesis is achieved for the dimerization AC. Complexation AC TKS159 leads shielding one two surfaces prochiral molecule. diastereomeric AC−TKS complexes, i.e., re-AC−TKS and si-AC−TKS, were characterized by changes in UV−vis, fluorescence, circular dichroism spectra excited-state lifetimes. ee not simply determined ratio re-...

The mechanism for the chirogenesis in photocyclodimerization of 2-anthracenecarboxylate (AC) bound to human serum albumin (HSA) was investigated using time-resolved fluorescence measurements presence HSA inhibitors and/or an AC singlet excited state quencher. photophysical studies were correlated with product explain high enantiomeric excess (ee) observed chiral photoproducts. binds five different binding sites decreasing affinities. highest affinity (sites 1 and 2) is unreactive, can be...

Enantiodifferentiating geometrical photoisomerizations of (Z)-cyclooctene and (Z,Z)-1,3-cyclooctadiene were performed by using the pyromellitate-linked cyclodextrin network polymer, termed "cyclodextrin nanosponge (CDNS)", as a supramolecular sensitizing host. The photochirogenic behavior nanosponges incorporating β- or γ-cyclodextrin was significantly different from that reported for conventional sensitizer-appended monomeric cyclodextrins, affording chiral (E)-cyclooctene...

An unprecedented 2:2 complex was shown to intervene in the enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid (A) mediated by a hydrogen-bonding template l-prolinol (P) accelerate formation chiral anti-head-to-head and achiral syn-head-to-head cyclodimers >99% combined yield with enhanced enantioselectivities up 72% ee for former. The supramolecular complexation photochirogenic behaviors, as well plausible structures, intervening Am·Pn complexes (m, n = 1 or 2) were...

The UV-protective ability of mycosporine-like amino acids (MAAs) has been well documented and is believed to serve as a protecting agent for marine organisms from solar radiation. However, the effective UV absorption by MAAs not correlated MAA (neutral) structures. In this study, origin UV-protecting was elucidated experimental theoretical spectroscopic investigations. maxima mycosporine-glycine shinorine in UVA region were practically unaffected over wide range pH 4-10 only slightly...

Competitive cross-/homo-photocyclodimerization of anthracene (AN) and 2-anthracenecarboxylic acid (AC) mediated by a chiral hydrogen-bonding template (TKS) was investigated under various conditions. The cross-photocyclodimerization favored factor 4–5 at all temperatures wavelengths examined to afford the AC-AN cross-dimer in 80–84% yield even AN/AC = 1 98% 10. enantiomeric excesses (ee's) obtained were 27–47% for homo-dimers 21–24% cross-dimer. absolute configuration determined comparing...

A simple strategy for choosing optimal bio-supramolecular mediators from the mammalian serum albumin library is proposed bimolecular photochirogenic reactions. Thus, enantiodifferentiating photocyclodimerization of 2-anthracencecarboxylate (AC) was optimized in chemical and optical yields, when mediated by porcine canine albumins, both which bound two AC molecules first productive site to give (P)-enantiomer syn-head-to-tail-cyclodimer 69% yield 89% enantiomeric excess (ee) former but...

Enantiodifferentiating photocyclodimerization of 2-anthracenecarboxylic acid (AC-H) and its lithium salt (AC-Li) in chiral ionic liquid (CIL), (R)-1-(2,3-dihydroxypropyl)-3-methylimidazolium acetate {[(R)-GLYMI][AcO]}, gave a mixture two head-to-tail (HT) head-to-head (HH) cyclodimers HT/HH ratios 1.3-1.7 (for AC-H) 2.2-4.3 AC-Li) with low enantiomeric excesses (ee) 0-3% for syn-HT anti-HH dimers. In contrast, irradiation AC-H an aqueous solution, containing cucurbit[8]uril (CB[8]) as host...

Circular dichroism (CD) spectral examinations at various host/guest ratios revealed that 2-anthracenecarboxylic acid (AC) forms not only 1:1 but also novel 2:1 hydrogen-bonded/π-stacked complexes with a chiral 4-benzamidoprolinol template (TKS159). The complexation is minor process causes significant CD changes as consequence of the exciton coupling interaction two AC chromophores and greatly accelerates head-to-head photocyclodimerization to significantly affect stereochemical outcomes.

Proteins in solution are conventionally considered macromolecules. Dynamic microscopic structures supersaturated protein solutions have received increasing attention the study of crystallisation and formation misfolded aggregates. Here, we present a method for observing rotational dynamic that can detect interaction nanoscale lysozyme networks via diffracted X-ray tracking (DXT). Our DXT analysis demonstrated rearrangement behaviours or clusters, which driven by local density concentration...

Abstract Ultrahigh sensitivity chiral HPLC analysis of nonfluorescent cyclodimers 2-anthracenecarboxylic acid (AC) was achieved with much improved accuracy and reproducibility through a nonconventional on-detector photoreversion/re-excitation/detection mechanism. Excitation at 254 nm in the detector cuvette caused photoreversion to AC, situ excitation which led strong fluorescence longer λ. The enhanced by factor ca. 2000 compared usual UV detection.

Chiral induction: Catalytic bio-supramolecular photochirogenesis is achieved for the enantiodifferentiating [4+4] photocyclodimerization of 2-anthracenecarboxylate by repeatedly using human serum albumin (HSA) as a chiral mediator; original high enantiomeric excess values (up to 80–90 %) are preserved.

Chiral variants of amyloid fibrils prepared by agitating acidified solutions bovine insulin at 45 °C not only induced quasi-mirror-imaged circular dichroism spectra upon complexation with 2-anthracenecarboxylate but also gave anti-head-to-head-cyclodimers the opposite absolute configurations photoirradiation.