Constructing Microporous Ion Exchange Membranes via Simple Hypercrosslinking for pH-Neutral Aqueous Organic Redox Flow Batteries.

Ion exchange membranes (IEMs) play a critical role in aqueous organic redox flow batteries (AORFBs). Traditional IEMs that feature microphase-separated microstructures are well-developed and easily available but suffer from the conductivity/selectivity tradeoff. The emerging charged microporous polymer membranes show the potential to overcome this tradeoff, yet their commercialization is still hindered by tedious syntheses and demanding conditions. We herein combine the advantages of these two types of membrane materials via simple in situ hypercrosslinking of conventional IEMs into microporous ones. Such a concept is exemplified by the very cheap commercial quaternized polyphenylene oxide membrane. The hypercrosslinking treatment turns poor-performance membranes into high-performance ones, as demonstrated by the above 10-fold selectivity enhancement and much-improved conductivities that more than doubled. This turn is also confirmed by the effective and stable pH-neutral AORFB with decreased membrane resistance and at least an order of magnitude lower capacity loss rate. This battery shows advantages over other reported AORFBs in terms of a low capacity loss rate (0.0017 % per cycle) at high current density. This work provides an economically feasible method for designing AORFB-oriented membranes with microporosity.

Catalyst-controlled regio- and stereoselective synthesis of diverse 12H-6,12-methanodibenzo[d,g][1,3]dioxocines.

We describe an efficient one-pot regio- and stereoselective method for synthesizing diverse 1-hydroxy-12H-6,12-methanodibenzo[d,g][1,3]dioxocines and 3-hydroxy-12H-6,12-methanodibenzo[d,g][1,3]dioxocines using ethylenediammonium diacetate (EDDA) or p-toluenesulfonic acid (PTSA) catalyzed reactions between various resorcinols and a number of 2-hydroxychalcones. These reactions involve a catalyst-controlled cascade Michael-type reaction/double cyclization process. Importantly, these reactions provide a rapid synthetic route to the production of biologically interesting complex molecules that are generally prepared using multi-step reactions.

Regioselective construction of diverse and multifunctionalized 2-hydroxybenzophenones for sun protection by indium(iii)-catalyzed benzannulation.

Diverse and functionalized 2-hydroxybenzophenone derivatives were synthesized efficiently in good to excellent yield via the highly regioselective indium(iii)-catalyzed [2+2+2] benzannulation of 3-formylchromones with ß-enamino esters or ß-enamino ketones. This benzannulation reaction proceeds via a domino Michael/retro-Michael/6π-electrocyclization/deformylation reaction. In addition, 2-hydroxybenzophenones were also prepared by the indium(iii)-catalyzed [4+2] benzannulation reaction between 3-substituted chromen-4-ones and ß-enamino esters or ß-enamino ketones. Furthermore, the effects of substituents and π conjugation on the characteristics of the UV-Vis spectrum of synthesized 2-hydroxybenzophenones were examined. Compound 10s exhibited higher sun protection activity than oxybenzone which is used in most popular sunscreens.