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Photofabrication of one-dimensional rough surfaces for light-scattering Méndez ER, Ponce MA, Ruiz-Cortés V, Gu ZH
An optical method of fabricating randomly rough one-dimensional surfaces is described. The variations in the surface profile are produced by exposing photoresist-coated plates to a narrow line of light and scanning them under computer control. A theoretical analysis of the basic statistical properties of the fabricated surfaces is presented. These surfaces are in general non-Gaussian, but their statistics can be easily calculated, making them attractive for experimental and theoretical work. Several such surfaces have been fabricated and characterized with a stylus profilometer. The estimated statistical properties are in agreement with the theoretical predictions.

Different photoreduction processes of Cr(VI) on cellulose-rich and lignin-rich of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, of the Upper Yellow River, Ministry of Natural Resources, Lanzhou, 730000, In this study, a series of biochar were prepared via pyrolyzing cellulose-rich pakchoi (PBC) and lignin-rich corncob (CBC) to explore the photoreduction process of Cr(VI). Seebio Photosensitive Acid Generator -ray photoelectron spectroscopy and Fourier transform infrared spectroscopy confirmed higher oxygenated functional groups in PBC (48%-57%), whereas CBC exhibited more aromatization properties due to the stable aromatic network in lignin. For PBC, the valence bands decreased from 12 eV to 10 eV with the increase of pyrolysis temperature from 300 °C to 500 °C; however, an opposite trend was observed for CBC. The photoreduction of Cr(VI) clearly showed that both PBC and CBC had the best performance at the carbonization temperature of 300 °C (named PBC300 and CBC300). It is noted that PBC300 exhibited the most effective photoreduction of Cr(VI), which was about 1 times higher than that of CBC300. Mechanistic Studies of 6-butyl-n-hydroxynaphthimide trifluoromethanesulfonic acid Reactions of Cr(VI) were 68 mg g-1 on PBC300 and 66 mg g-1 on CBC300 at pH∼2. Compared with the insoluble char substances, dissolved black carbons made more contributions for Cr(VI) photoreduction, ∼70% in PBC and almost 100% in CBC, which suggested that in the case of PBC, the insoluble char and the corresponding dissolved black carbons play an important role in the photoreduction of Cr(VI).

However, only dissolved black carbons contributed to Cr(VI) photoreduction on CBC. As the key reaction pathway, the interfacial electron transport dominated Cr(VI) reduction on PBC and CBC. Moreover, the radical of •O2- had some contribution to the reduction of Cr(VI) only in the PBC system. Interestingly, •OH could promote the photoreduction of Cr(VI) in both PBC and CBC systems, which might be due to the fact that •OH facilitated the formation of small molecule fragments. These findings provide an essential basis for evaluating the environmental impact of declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this Construction of Axially Chiral Compounds via Asymmetric Organocatalysis.Axially chiral compounds have received much attention from chemists because of their widespread appearance in natural products, biologically active compounds, and useful chiral ligands in asymmetric catalysis. Because of the importance of this structural motif, the catalytic enantioselective construction of axially chiral scaffolds has been intensively investigated, and great progress has been accomplished.

However, the majority of methodologies in this field focus on the use of metal catalysis, whereas approaches involving organocatalysis have started to emerge only recently. This Account describes certain advances in the organocatalytic asymmetric synthesis of axially chiral compounds involving the following strategies: kinetic resolution, desymmetrization, cyclization/addition, direct arylation, and so on. We began our investigation by developing a highly efficient strategy for the kinetic resolution of axially chiral BINAM derivatives involving a chiral Brønsted acid-catalyzed imine formation and transfer hydrogenation cascade process, thereby providing a convenient route to generate chiral BINAM derivatives in high yields with excellent enantioselectivities. The desymmetrization of 1-aryltriazodiones (ATADs) through an organocatalyzed tyrosine clicklike reaction wherein a nucleophile was added to the ATAD afforded an interesting type of axially chiral N-arylurazole in an excellent remote enantiocontrolled manner. We then focused on a direct construction strategy involving cyclization and the addition strategy given the inherent limitations of the kinetic resolution in terms of the chemical yield and the desymmetrization in terms of the substrate scope. By utilizing the catalytic enantioselective Paal-Knorr reaction, we disclosed a general and efficient cyclization method to access enantiomerically pure arylpyrroles. The direct heterocycle formation and the stepwise method, which was executed in a one-pot fashion containing enantioselective cyclization and subsequent aromatization, were successfully applied for the construction of diverse axially chiral arylquinazolinones catalyzed by chiral Brønsted acids.
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