Notes

The correlation of the spin at the ring π-electron system and the pEDA(D) descriptor shows that the electron charge supplied to the ring π-electron system and the spin flow oppositely
interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the Degradation of estriol (E3) and transformation pathways after applying photochemical removal processes in natural surface water.Bárbara, s/n, PR, 85601-970, Paraná, Brazil.Catarina, s/n - Trindade, Florianópolis - SC, 88040-900, Florianópolis, Santa 99700-000, Erechim, Rio Grande do Sul, Brazil.Steroidal hormones such as estriol (E3), are resistant to biodegradation; hence their removal by conventional treatment systems (aerobic and anaerobic) facilities is limited. These substances are detected in surface water, and present risks to the aquatic ecosystem and humans via potential biological activity.

Photochemical treatments can be used to remove E3; however, just a few studies have analyzed the kinetics, intermediates, and E3 degradation pathways in natural surface water. In this study, the behavior of E3 under ultraviolet irradiation associated with H2O2, O3 or TiO2 was investigated to determine the degradation potential and the transformation pathways in reactions performed with a natural surface water sample. E3 degradation kinetics (200 ppb) fitted well to the pseudo-first-order kinetics model, with kinetic constant k in the following order: kUV/O3 > kUV/TiO2 > kUV/H2O2 > kUV. The mechanism of degradation using different advanced oxidative processes seemed to be similar and 12 transformation byproducts were identified, with 11 of them being reported here for the first time. The byproducts could be formed by the opening of the aromatic ring and addition of a hydroxyl radical. A possible route of E3 degradation was proposed based on the byproducts identified, and some of the byproducts presented chronic toxicity to aquatic organisms, demonstrating the Negative Charge as a Lens for Concentrating Antiaromaticity: Using a Pentagonal "Defect" and Helicene Strain for Cyclizations.Incorporation of a five-membered ring into a helicene framework disrupts aromatic conjugation and provides a site for selective deprotonation.

The deprotonation creates an anionic cyclopentadienyl unit, switches on conjugation, leads to a >200 nm red-shift in the absorbance spectrum and injects a charge into a helical conjugated π-system without injecting a spin. Structural consequences of deprotonation were revealed via analysis of a monoanionic helicene co-crystallized with K+ (18-crown-6)(THF) and Cs+ 2 (18-crown-6)3 . UV/Vis-monitoring of these systems shows a time-dependent formation of mono- and dianionic species, and the latter was isolated and crystallographically characterized. Seebio Photobase Generator of the twisted helicene frame to delocalize the negative charge was probed as a perturbation of aromaticity using NICS scans. Relief of strain, avoidance of antiaromaticity, and increase in charge delocalization assist in the additional dehydrogenative ring closures that yield Fabrication of Patterned Hydrogel Interfaces: Exploiting the Maleimide Group as a Dual Purpose Handle for Cross-Linking and Bioconjugation.Functional hydrogels that can be obtained through facile fabrication procedures and subsequently modified using straightforward reagent-free methods are indispensable materials for biomedical applications such as sensing and diagnostics. Herein a novel hydrogel platform is obtained using polymeric precursors containing the maleimide functional group as a side chain.

The maleimide groups play a dual role in fabrication of functional hydrogels. They enable photochemical cross-linking of the polymers to yield bulk and patterned hydrogels. Moreover, the maleimide group can be used as a handle for efficient functionalization using the thiol-maleimide conjugation and Diels-Alder cycloaddition click reactions. Obtained hydrogels are characterized in terms of their morphology, water uptake capacity, and functionalization. Micropatterned hydrogels are obtained under UV-irradiation using a photomask to obtain reactive micropatterns, which undergo facile functionalization upon treatment with thiol-containing functional molecules such as fluorescent dyes and bioactive ligands. The maleimide group also undergoes conjugation through the Diels-Alder reaction, where the attached molecule can be released through thermal treatment via the retro Diels-Alder reaction. The antibiofouling nature of these hydrogel micropatterns enables efficient ligand-directed biomolecular immobilization, as demonstrated by attachment of streptavidin-coated quantum dots.

Extended Bis(benzothia)quinodimethanes and Their Dications: From Singlet Diradicaloids to Isoelectronic Structures of Long Acenes.Singapore, 119260, Singapore, Singapore.Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Extended bis(benzothia)quinodimethanes and their dications were synthesized as stable species. The neutral compounds mainly have a quinoidal structure in the ground state but show increased diradical character with extension of the central quinodimethane unit.
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