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The magnetic circular dichroism (MCD) spectra of metal complexes of tetrakis(thiadiazole)porphyrazines ([TTDPzM] with M = 2HI, ZnII, MgII(H2O), and CdII) have been recorded in dimethyl formamide solution. Together with the UV–Vis spectra, the MCD spectra provide useful information about the structure and electronic properties of the complexes. The experimental UV–Vis and MCD spectra compare pretty...
Bridged bicyclic amino acids have high potential applicability as self‐organized, conformationally constrained synthetic building blocks that do not require assistance from hydrogen bond formation. We systematically investigated the intrinsic conformational propensities of dipeptides of bridged bicyclic β‐amino acids by means of accelerated molecular dynamics simulation and density functional theory...
Chiral hemiaminals (5‐8RR and 5‐8SS) have been synthesized from the corresponding 2‐iminothiazolidine‐4‐ones (1‐4RR and 1‐4SS) by LiAlH4 reductions stereoselectively and were then converted to single enantiomer thiazol‐2‐imines (9‐12RR and 9‐12SS) by a water elimination reaction. The kinetics of the dehydration reactions which occurred spontaneously both in the solid state and in the solution have...
Two different columns—Lux Cellulose‐1 and Chiralpak CBH—were evaluated for their chiral recognition abilities for eight drugs comprising three β‐blockers, one antacid, and four cathinones in polar‐organic elution mode and reversed‐phase elution mode, respectively. The factors that affected the enantioseparation were tested and optimized to develop a suitable chiral separation method whose LC conditions...
A 1:1 mixture of pseudoenantiomer ethynylhelicene (P)‐pentamer and (M)‐tetramer in toluene formed hetero‐double‐helix and their self‐assembled gels. Kinetic analysis under isothermal conditions showed a complex nonlinear nature with regard to temperature changes. At 60°C, sigmoidal kinetics were observed, which disappeared after seeding with the self‐assembled gels. These findings indicate the involvement...
Two western red cedar pinoresinol‐lariciresinol reductase (PLR) homologues were studied to determine their enantioselective, substrate versatility, and kinetic properties. PLRs are downstream of dirigent protein engendered, coniferyl alcohol derived, stereoselective coupling to afford entry into the 8‐ and 8′‐linked furofuran lignan, pinoresinol. Our investigations showed that each PLR homolog can...
Moving from the simple concept that reflection onto a mirror surface changes the handedness of circularly polarized light, we describe what happens to the emergent polarization in two different cases after reflection on a back mirror. In the first case, a regular emitter is taken into account, where reflection has the effect to destroy the emergent polarization. In the second case, we show what could...
4‐l‐menthyloxycarbonyl 5‐aryl prolinates were studied as organocatalysts of a novel three‐component reaction of cyclohexanone, benzoic acid, and β‐nitrostyrene. The presence of ortho‐halogen atom in 5‐aryl fragment of the catalyst is favored for driving the formation of chiral 7a‐hydroxyoctahydro‐2H‐indol‐2‐one scaffold. 5‐(o‐Chlorophenyl) prolinate selectively afforded 3‐phenyl‐7a‐hydroxyoctahydro‐2...
It has been recently shown that enantiomers of the helicoidal paddlewheel complex [Co3(dpa)4(CH3CN)2]2+ (dpa = the anion of 2,2′‐dipyridylamine) can be resolved using the chiral [As2(tartrate)2]2− anion (AsT) and that these complexes demonstrate a strong chiroptical response in the ultraviolet‐visible and X‐ray energy regions. Here we report that the nickel congener, [Ni3(dpa)4(CH3CN)2]2+, can likewise...
Up to date, functionalized graphene–based membranes have exhibited a promising potential in the enantioseparation. However, since precisely controlling the interlayer distance of two‐dimensional materials is a great challenge in practical experiments, the transport mechanism of chiral guests in such membranes, together with various critical parameters that play a controlling role in the transport...
Vibrational Raman optical activity (ROA) spectra were calculated under off‐resonance, near‐resonance, and at‐resonance conditions for
(A) and under off‐resonance conditions for
(B) using a new driver software for calculating the ROA intensities from complex (damped) time‐dependent linear response Kohn‐Sham theory. The off‐resonance spectra of A and B show many similarities...
In this work, the 3‐D structure of the well‐known opioid drug heroin in a solution was investigated. The goal was to provide a complete and detailed description of the stable conformers with their relative abundances. This knowledge is very important from the pharmaceutical and forensic point of view as it could help significantly with deeper understanding of heroin's metabolism and the development...
Rapid derivatization of chiral 1,2‐diols with dinaphthyl borinic acid (DBA) leads to a cyclic boronate, enabling the absolute stereochemical prediction via exciton‐coupled circular dichroic (ECCD) of the naphthyl groups. Aryl‐ and alkyl‐substituted 1,2‐diols derivatized with DBA yield a predictable ECCD, which is also in agreement with theoretical predictions derived from computationally minimized...
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