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This study presents the synthesis and characterization of a highly conjugated stable diradical molecule composed of a donor–acceptor coupling unit. The optical, electrochemical, and spintronic properties of this molecule were comprehensively investigated. Triphenylamine served as the electron donor, while 2,1,3-benzothiadiazole was utilized as the electron acceptor for constructing the backbone of the diradical molecule. Two pendant nitronyl nitroxide radicals were incorporated onto the triphenylamine moiety. A comparative study between our diradical molecule and a reference counterpart with only a donor group as the coupling unit revealed intriguing differences in optical properties and singlet-to-triplet energy gap. Our findings demonstrate that the D–A effect induces intramolecular charge polarization on the coupling unit, which subsequently influences the spin–spin interactions of the diradical molecules. Thus, our results offer novel insights into the effective preparation of fully conjugated and stable diradicals, as well as providing a convenient approach for tuning the spintronic and magnetic properties of diradical materials. [ABSTRACT FROM AUTHOR]

Heteroatom-doped porous carbon materials are highly desired for supercapacitors. Herein, we report the preparation of such material from polybenzoxazine (PBZ), a kind of phenolic resin. Four different N- and O-codoped microporous carbon materials were obtained by changing carbonization temperature (600, 700, 800, and 900 °C). Their structures were characterized by scanning electron microscopy (SEM), nitrogen isothermal absorption and desorption, X-ray diffraction (XRD), Raman spectroscopy, elemental analysis and X-ray photoelectron spectroscopy (XPS), and their electrochemical performances were evaluated by cyclovoltammetry (CV) and galvanostatic charge–discharge (GCD) test in a three-electrode system. It was found that the carbon material (C-700) prepared at the carbonization temperature of 700 °C possesses the largest specific surface area (SSA), total pore volume and average pore size among the family, and thus displays the highest specific capacitance with a value of 205 F g−1 at a current density of 0.25 A g−1 and good cycling stability. The work demonstrates that the N- and O-codoped microporous carbon materials with high electrochemical performance can be derived from benzoxazine polymers and are promising for supercapacitor application. [ABSTRACT FROM AUTHOR]

For most graphene electrodes, there is usually a disappointing trade-off relationship between gravimetric and volumetric capacitive characteristics, which is definitely a major stumbling block in the development of real-life supercapacitors with high energy density. Herein, we rationally designed a hierarchically porous and modestly packed diamine pillared graphene, which is achieved by a facile and straightforward reaction between commercialized bulk graphite fluoride and in situ generated diamine anions. Combined reliable characterization studies demonstrate that an advantageous reductive defluorination of the unsubstituted carbon–fluorine units (C–Fx) accompanies the foreseen substitution of C–Fx by diamines, endowing the resultant products with recovered 2D π-conjugation and high conductivity. In comparison to ethylenediamine and p-phenylenediamine, pseudocapacitive 4,4′-oxydianiline (ODA) molecular pillars, having a bulky and rigid geometry, provide the ODA-G product with a greatly widened d-spacing (6.2 Å), large wettable and electrolyte-accessible specific surface area (1985 m2 g−1), hierarchically porous and interconnected structuration, heavyweight nature (density of 1.08 g cm−3), etc. Consequently, the symmetric supercapacitor fabricated using ODA-G as both electrodes delivers an impressive gravimetric capacitance of 328.5 F g−1 and a maximized volumetric capacitance of 354.8 F cm−3 at a current density of 0.5 A g−1, whilst exhibiting a remarkable rate capability and cycling stability. Apart from an exceptional gravimetric energy density, the volumetric energy density of the ODA-G device is as high as 19.5 W h L−1 at a large power density of 9093 W L−1. It is notable that this contribution deepens our insight into the chemistry of graphite fluoride, and can guide the judicious design and synthesis of versatile functionalized graphene applicable to other electrochemical energy-storage systems, or the newly-emerging photothermal water evaporation, desalination, etc. [ABSTRACT FROM AUTHOR]

Background: Glomerular filtration rate (GFR) is a useful index in many clinical conditions. However, very few studies have assessed the performance of full age spectrum (FAS) equation and the Asian modified Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation in the approximation of GFR in Chinese patients with chronic kidney disease., Objective: This study aimed to compare the diagnostic performance of the above two creatinine-based equations., Methods: A well designed single-center cross-sectional study was performed and the GFR was determined by 3 methods separately in the same day: technetium-99m-diethylene triamine pentaacetic acid ( 99m Tc-DTPA) dual plasma sample clearance method (mGFR); FAS equation method; Asian modified CKD-EPI equation method. The gold standard method was the mGFR. Equations performance criteria considered correlation coefficient, bias, precision, accuracy and the ability to detect the mGFR less than 60ml/min/1.73m 2 ., Results: A total of 160 patients were enrolled. The diagnostic performance of FAS showed no significant difference in the correlation coefficient (0.89 vs 0.89), precision (15.9 vs 16.1ml/min/1.73m 2 ), accuracy (75.0% vs 76.3%) and the ability to detect the mGFR less than 60ml/min/1.73m 2 (0.94 vs 0.94) compared with the Asian modified CKD-EPI equation in all participants. The FAS showed a negative bias, while the new CKD-EPI equation showed a positive bias (-1.20 vs 1.30ml/min/1.73m 2 , P<0.001). However, they were all near to zero. In the mGFR<60ml/min/1.73m 2 subgroup and mGFR>60ml/min/1.73m 2 subgroup were consistent with that in the whole cohort. The precision and accuracy decreased when GFR>60ml/min/1.73m 2 in both equations., Conclusions: The FAS equation and the Asian modified CKD-EPI equation had similar performance in determining the glomerular filtration rate in the Chinese patients with chronic kidney disease. Both the FAS equation and Asian modified CKD-EPI can be a satisfactory method and may be the most suitable creatinine-based equation., (Copyright © 2020 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.)