N-methyl-D-aspartic acid (NMDA) receptors transiently transfected into mammalian HEK-293 cells were characterized with subunit-specific antibodies and electrophysiological recordings. Deactivation time course recorded in response to fast-glutamate pulses were studied in isolated and lifted cells, as well as in outside-out membrane patches excised from cells expressing recombinant NR1 subunits in combination with the NR2A, NR2B, NR2C, or NR2D NMDA receptor subunits. Transfected cells were preidentified by the fluorescence emitted from the coexpressed Aequorea victoria jellyfish Green Lantern protein. Currents generated by NR1/NR2A channels displayed double exponential deactivation time course being faster than that in NR1/NR2B or NR1/NR2C channels. However, a large decay variability was observed within each cotransfection, suggesting that mechanisms additional to subunit composition may also regulate deactivation time course. NR1/NR2D channels displayed slowly deactivating currents. Channel deactivation was fast and comparable among receptors obtained by cotransfecting five distinct spliced variants of the NR1 subunit, each with the NR2A subunit. Additionally, recovery from desensitization was slower for NR1/NR2B than for NR1/NR2A channels. The average deactivation time course of responses to brief L-glutamate applications in cells where NR1/NR2A/NR2B cDNAs were cotransfected at variable ratio was intermediate between those of the NR1/NR2A and NR1/NR2B channels. Although immunocytochemical evidence indicates that the majority of cells are cotransfected by all plasmids in triple transfection, our experimental condition did not allow for a tight control of the expression of NMDA receptor subunits. This produced the result that many cells were characterized by deactivation time course and haloperidol sensitivities of separate NR1/NR2A and NR1/NR2B subunit heteromers. We also speculate on the possible formation of channels resulting from the coassembly in the same receptor of NR1/NR2A/NR2B subunits from a minority of cells that gave responses to brief application of L-glutamate characterized by slow deactivation time course and decreased haloperidol sensitivity.

We describe carbazolyl dicyanobenzene (CDCB)-based donor–acceptor (D–A) fluorophores as a class of cheap, easily accessible, and efficient metal-free photoredox catalysts for organic synthesis. By changing the number and position of carbazolyl and cyano groups on the center benzene ring, CDCBs with a wide range of photoredox potentials are obtained to effectively drive the energetically demanding C­(sp3)–C­(sp2) cross-coupling of carboxylic acids and alkyltrifluoroborates with aryl halides via a photoredox/Ni dual catalysis mechanism. This work validates the utility of D–A fluorophores in guiding the rational design of metal-free photoredox catalysts for visible-light-promoted organic synthesis.

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Liu and co-workers reported a series of rationally designed two-electron storage viologen molecules as anolytes for high-voltage and high-power pH-neutral aqueous organic redox flow batteries. The synthetic and computational chemistry presented has opened a new avenue for designing energy-dense redox-active organic molecules for building neutral AORFBs with high power density and high energy density, and it promises economical, benign, and widespread uses of redox flow batteries in large-scale energy storage. HIGHLIGHTSTwo-electron storage viologens were designed for energy-storage applications Neutral aqueous organic redox flow batteries up to 1.38 V and 130 mW/cm 2 An integrated approach of synthesis, electrochemistry, and computational modelling Molecular engineering is a powerful strategy for developing redox-active molecules DeBruler et al., Chem 3, 961-978 December 14, 2017 ª SUMMARYAqueous organic redox flow batteries (AORFBs) are highly attractive for largescale energy storage because redox-active organic molecules are synthetically tunable, sustainable, and potentially low cost. Here, we show that rational molecular engineering yielded a series of two-electron storage viologen molecules as anolyte materials for AORFBs. In neutral NaCl solutions, these viologen anolytes have a theoretical capacity of up to 96.5 Ah/L in H 2 O and exhibit a reduction potential as low as À0.78 V versus normal hydrogen electrode. The neutral aqueous flow batteries with two two-electron storage viologen molecules delivered a cell voltage of up to 1.38 V and outstanding battery performance, including a power density of up to 130 mW/cm 2 , capacity retention of up to 99.99% per cycle, and energy efficiency of up to 65% at 60 mA/cm 2 . Density functional theory calculations revealed that the 1e À and 2e À reduced redox states of these molecules were stabilized by the high charge delocalization of their frontier SOMO or HOMO.