Chemoenzymatic Polymerization of l-Serine Ethyl Ester in Aqueous Media without Side-Group Protection

AbstractSolution behaviors of poly(styrene-co-sodium methacrylate) were studied by fluorescence spectroscopic methods using pyrene as a probe. The mol% of methacrylate was in the range 3.6–9.4. Water and N,N-dimethylforamide(DMF) mixture was used as a solvent (DMF/water = 0.2 mol %). The critical micelle (or aggregation) concentrations of ionomers and the partition coefficients of pyrene were obtained the temperature range 10–80°C. At room temperature, the values of CMCs (or CACs) were in the range 4.7 ×10-6 5.3 ×10-6 g/mL and we could not find any notable effect of the content of ionic repeat units within the experimental errors. Unlike CMCs, as the ion content increased, partitioning of pyrene between the hydrophobic aggregates and an aqueous media decreased from 1.5 ×105 to 9.4 ×104. As the temperature increased from 10 to 80 °C, the values of CMCs increased less than one order of magnitude. While, the partition coefficients of pyrene decreased one order of magnitude and the effect of the ion content became negligible.

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Host-Guest Interactions on Electrode Surfaces for Immobilization of Molecular Catalysts

10.26434/chemrxiv.12115026.v1 ◽

2020 ◽

Author(s):

Laurent Sévery ◽

Jacek Szczerbiński ◽

Mert Taskin ◽

Isik Tuncay ◽

Fernanda Brandalise Nunes ◽

...

Keyword(s):

Aqueous Media ◽

Heterogeneous Systems ◽

Catalytic Systems ◽

New Approach ◽

Molecular Systems ◽

Electrode Surfaces ◽

Catalytic Surfaces ◽

Oxide Electrodes ◽

The Stability ◽

Molecular Catalysts

The strategy of anchoring molecular catalysts on electrode surfaces combines the high selectivity and activity of molecular systems with the practicality of heterogeneous systems. The stability of molecular catalysts is, however, far less than that of traditional heterogeneous electrocatalysts, and therefore a method to easily replace anchored molecular catalysts that have degraded could make such electrosynthetic systems more attractive. Here, we apply a non-covalent “click” chemistry approach to reversibly bind molecular electrocatalysts to electrode surfaces via host-guest complexation with surface-anchored cyclodextrins. The host-guest interaction is remarkably strong and allows the flow of electrons between the electrode and the guest catalyst. Electrosynthesis in both organic and aqueous media was demonstrated on metal oxide electrodes, with stability on the order of hours. The catalytic surfaces can be recycled by controlled release of the guest from the host cavities and readsorption of fresh guest. This strategy represents a new approach to practical molecular-based catalytic systems.

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Self-Recognizing π-π Stacking Interactions Designed for the Generation of Ultrastable Mesoporous Hydrogen-Bonded Organic Frameworks

10.26434/chemrxiv.9729494 ◽

2019 ◽

Author(s):

KAIKAI MA ◽

Peng Li ◽

John Xin ◽

Yongwei Chen ◽

Zhijie Chen ◽

...

Keyword(s):

Pore Size ◽

Fiber Composite ◽

Aqueous Media ◽

Stacking Interactions ◽

Mustard Gas ◽

X Ray Diffraction ◽

X Ray ◽

Expansion Strategy ◽

Π Stacking ◽

Hydrogen Bonded

Creating crystalline porous materials with large pores is typically challenging due to undesired interpen-etration, staggered stacking, or weakened framework stability. Here, we report a pore size expansion strategy by self-recognizing π-π stacking interactions in a series of two-dimensional (2D) hydrogen–bonded organic frameworks (HOFs), HOF-10x (x=0,1,2), self-assembled from pyrene-based tectons with systematic elongation of π-conjugated molecular arms. This strategy successfully avoids interpene-tration or staggered stacking and expands the pore size of HOF materials to access mesoporous HOF-102, which features a surface area of ~ 2,500 m2/g and the largest pore volume (1.3 cm3/g) to date among all reported HOFs. More importantly, HOF-102 shows significantly enhanced thermal and chemical stability as evidenced by powder x-ray diffraction and N2 isotherms after treatments in chal-lenging conditions. Such stability enables the adsorption of dyes and cytochrome c from aqueous media by HOF-102 and affords a processible HOF-102/fiber composite for the efficient photochemical detox-ification of a mustard gas simulant.

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CELLULOSE CELLETS AS NEW TYPE OF ADSORBENT FOR THE REMOVAL OF DYES FROM AQUEOUS MEDIA

Environmental Engineering and Management Journal ◽

10.30638/eemj.2015.056 ◽

2015 ◽

Vol 14 (3) ◽

pp. 525-532 ◽

Cited By ~ 12

Author(s):

Daniela Suteu ◽

Gabriela Biliuta ◽

Lacramioara Rusu ◽

Sergiu Coseri ◽

Gabriela Nacu

Keyword(s):

Aqueous Media ◽

New Type

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