Recent progress reveals that, in the methanol-to-olefin (MTO) process on acidic zeolites, the conversion of an equilibrium mixture of methanol and DME is dominated by a "hydrocarbon pool" mechanism. However, the initial C-C bond formation, that is, the chemistry during the kinetic "induction period" leading to the reactive hydrocarbon pool, still remains unclear. With the application of a stopped-flow protocol, in the present work, pure surface methoxy groups [SiO(CH(3))Al] were prepared on various acidic zeolite catalysts (H-Y, H-ZSM-5, H-SAPO-34) at temperatures lower than 473 K, and the further reaction of these methoxy species was investigated by in situ (13)C MAS NMR spectroscopy. By using toluene and cyclohexane as probe molecules which are possibly involved in the MTO process, we show the high reactivity of surface methoxy species. Most importantly, the formation of hydrocarbons from pure methoxy species alone is demonstrated for the first time. It was found that (i) surface methoxy species react at room temperature with water to methanol, indicating the occurrence of a chemical equilibrium between these species at low temperatures. In the presence of aromatics and alkanes, (ii) the reactivity of surface methoxy groups allows a methylation of these organic compounds at reaction temperatures of ca. 433 and 493 K, respectively. In the absence of water and other organic species, that is, under flow conditions and on partially methylated catalysts, (iii) a conversion of pure methoxy groups alone to hydrocarbons was observed at temperatures of T >/= 523 K. This finding indicates a possible formation of the first hydrocarbons during the kinetic induction period of the MTO process via the conversion of pure surface methoxy species (case iii). After the first hydrocarbons are formed, or in the presence of a small amount of organic impurities, surface methoxy groups contribute to a further methylation of these organic compounds (case ii), leading to the formation of a reactive hydrocarbon pool which eventually plays an active role in the steady state of the MTO process at reaction temperatures of T >/= 573 K.

Nonaqueous redox fl ow batteries are emerging fl ow-based energy storage technologies that have the potential for higher energy densities than their aqueous counterparts because of their wider voltage windows. However, their performance has lagged far behind their inherent capability due to one major limitation of low solubility of the redox species. Here, a molecular structure engineering strategy towards high performance nonaqueous electrolyte is reported with signifi cantly increased solubility. Its performance outweighs that of the state-of-the-art nonaqueous redox fl ow batteries. In particular, an ionic-derivatized ferrocene compound is designed and synthesized that has more than 20 times increased solubility in the supporting electrolyte. The solvation chemistry of the modifi ed ferrocene compound. Electrochemical cycling testing in a hybrid lithium-organic redox fl ow battery using the assynthesized ionic-derivatized ferrocene as the catholyte active material demonstrates that the incorporation of the ionic-charged pendant signifi cantly improves the system energy density. When coupled with a lithium-graphite hybrid anode, the hybrid fl ow battery exhibits a cell voltage of 3.49 V, energy density about 50 Wh L −1 , and energy effi ciency over 75%. These results reveal a generic design route towards high performance nonaqueous electrolyte by rational functionalization of the organic redox species with selective ligand.

amount of cross-linked solid. According to the nature of solvents, gels are categorized into hydrogel and organogel to indicate whether the solvent is water or organic solvent(s), respectively. As to the gelation driving forces, gels can be classified into physical gels in which intermolecular interactions are responsible for gel formation, and chemical gels in which the gel skeleton is cross-linked by covalent bonds.Incorporation of metal components (metal ions, metal-organic molecules, and metal nanoparticles) is an effective way to locally establish extra interactions among the building blocks and consequently trigger gel formation, [2][3][4] weaken [5] or enhance [6] gel strength, and modify gel morphology. [7,8] Moreover, addition of metal components is a straightforward way to integrate the specific properties of metals with the properties of organic matrix, therefore to tune properties like conductivity, [9] color, [10,11] rheological behavior, [12] adsorption, [13] emission, [14] photophysical properties, [15] magnetism, [16,17] antibacterial activities, [18,19] catalytic activities, [20][21][22][23] redox activities, [24,25] and selfhealing properties. [26][27][28] Therefore, a broad response range to physical and chemical stimuli can be achieved. For instance, the incorporation of multivalence ions such as Fe 2+ /Fe 3+ , [25,29] Co 2+ / Co 3+ , [30] Cu + /Cu 2+ , [31] results in redox reactive hydrogels; the incorporation of magnetic nanoparticles like Fe 3 O 4[17] causes the gel to respond to external magnetic fields. In addition to the abovementioned intrinsically functional superiorities, metallogels can also serve as ideal templates to generate new materials, [13,22,23,32,33] such as 3D networks, [34] porous structures, [35] chiral materials, [36][37][38] quantum dots, [39] and nanorods. [40] Following the rapid advancement of exploration on the knowledge acquisition toward the major roles that metallogels are playing in catalysis, sensing, biomedicine, electronics, and optical devices, the focus of research has been transferred to the design principles of metallogels in the last decade. Owing to the advancements in the instrumental characterizations and theoretical calculations, [41] a number of pioneering efforts on metallogel design have been made and several innovative reviews have summarized these inspiring contributions. [32,[42][43][44] Despite their extensively acknowledged application advantages in many fields, the discovery of new metallogels with expected functionalities is still highly dependent on experimental screening and serendipity. The challenge stems from the susceptible balance among those complicated intermolecular interactions and the elaborate structure requirements of metallogels.Another research niche that needs to be clarified before discussing recent development of metallogels is: how to sort Introducing metal components into gel matrices provides an effective strategy to develop soft materials with advantageous properties such as: optical activity, conductivity, magn...

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A novel single-chain surfactant with multi-amine headgroups, bis(amidoethyl-carbamoylethyl) octadecylamine (C18N3), was synthesized. Electronmicrographic study showed that in aqueous solution C18N3 formed small micelles (10−20 nm in diameter) at pH 2.0 and changed into much larger globule vesicles sized about 0.6−2.0 μm in diameter at pH 6.8. At pH 12.0 vesicles changed to a much larger continued lyotropic lamella structure. At pH = 2, the surface tension (γ)−concentration (C) curve at pH 2 was an ordinary one, having one critical micelle concentration at 2.9 × 10-3 mol L-1 at relatively high surface tension (52 mN m-1). However, two unique transition points were observed in the γ−C plot at pH = 6.8 and 10.5, showing higher surface activity that is believed to be associated with the micelle−bilayer structure transition. The protonation degree pK a's of the three amine headgroups were found to be 6.6, 10.6, and 10.9, respectively, indicating that a complete protonation state of the headgroups occurred at pH 2.0, which is consistent with the apparent surface areas of headgroup calculated according to Gibbs adsorption isotherm. Variation of sizes and morphologies of C18N3 in aqueous solution at different pH values suggest that our synthetic surfactant may have great potential applications as a template in fabricating drug delivery, biosensors, and biomolecular devices.

ZIF-8 nanocrystals with a sub-100 nm size are prepared by a surfactant mediated method in aqueous solution. Pure ZIF-8 phase can be obtained with a stoichiometric Zn/2-methylimidazole ratio. The surfactant mixture of Span 80 and Tween 80 may stabilize the Zn/2-methylimidazole coordination structure and prevent the formation of the hydroxide or alkaline salt. The nanocrystals maintain a high specific surface area of 1360 m(2)/g. The particle size effect on the adsorption kinetics of the ZIF-8 nanocrystals is studied by using two different probing molecules (I3(-) anion and Rhodamine B molecule). For the I3(-) anion, which is smaller than the aperture size of ZIF-8, the ZIF-8 nanoparticles exhibit faster absorption kinetics compared to the bulk material. For the Rhodamine B molecule, which is larger than the aperture size of ZIF-8, only surface adsorption occurs. The enhanced adsorption kinetics of the ZIF-8 nanoparticles is attributed to the smaller particles size, which reduces the intraparticle diffusion length. ZIF-8 nanocrystals prepared by a surfactant mediated method in aqueous solution exhibit faster adsorption kinetics compared to the bulk material.

We report a series of ionically modified ferrocene compounds for hybrid lithium-organic non-aqueous redox flow batteries, based on the ferrocene/ferrocenium redox couple as the active catholyte material. Tetraalkylammonium ionic moieties were incorporated into the ferrocene structure, in order to enhance the solubility of the otherwise relatively insoluble ferrocene. The effect of various counter anions of the tetraalkylammonium ionized species appended to the ferrocene, such as bis(trifluoromethanesulfonyl)imide, hexafluorophosphate, perchlorate, tetrafluoroborate, and dicyanamide on the solubility of the ferrocene was investigated. The solution chemistry of the ferrocene species was studied, in order to understand the mechanism of solubility enhancement. Finally, the electrochemical performance of these ionized ferrocene species was evaluated and shown to have excellent cell efficiency and superior cycling stability.

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