01795nas a2200217   4500008004100000022001400041245008100055210006900136260009000205300000900295490000600304520100700310100002401317700001801341700002501359700001901384700001801403700001901421700002001440856011701460       2015                        eng d  a2041-172300aSelf-templated chemically stable hollow spherical covalent organic framework0 aSelftemplated chemically stable hollow spherical covalent organi  aMACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLANDbNATURE PUBLISHING GROUPcAPR  a67860 v63 a<p>Covalent organic frameworks are a family of crystalline porous materials with promising applications. Although active research on the design and synthesis of covalent organic frameworks has been ongoing for almost a decade, the mechanisms of formation of covalent organic frameworks crystallites remain poorly understood. Here we report the synthesis of a hollow spherical covalent organic framework with mesoporous walls in a single-step template-free method. A detailed time-dependent study of hollow sphere formation reveals that an inside-out Ostwald ripening process is responsible for the hollow sphere formation. The synthesized covalent organic framework hollow spheres are highly porous (surface area similar to 1,500m(2) g(-1)), crystalline and chemically stable, due to the presence of strong intramolecular hydrogen bonding. These mesoporous hollow sphere covalent organic frameworks are used for a trypsin immobilization study, which shows an uptake of 15.5 mu mol g(-1) of trypsin.</p>1 aKandambeth, Sharath1 aVenkatesh, V.1 aShinde, Digambar, B.1 aKumari, Sushma1 aHalder, Arjun1 aVerma, Sandeep1 aBanerjee, Rahul  uhttp://library.ncl.res.in/content/self-templated-chemically-stable-hollow-spherical-covalent-organic-framework-101778nas a2200205   4500008004100000245008700041210006900128260000800197300001600205490000700221520107100228100002001299700002801319700002201347700002401369700001901393700001801412700002401430856011801454       2018                        eng d00aSuperprotonic conductivity in flexible porous covalent organic framework membranes0 aSuperprotonic conductivity in flexible porous covalent organic f  cAUG  a10894-108980 v573 a<p>Poor mechanical stability of the polymer electrolyte membranes (PEMs) remains one of the bottlenecks towards improving the performance of the proton exchange membrane (PEM) fuel cells. The present work proposes a unique way to utilize crystalline covalent organic frameworks (COFs) as a self‐standing, highly flexible membrane to further boost the mechanical stability of the material without compromising its innate structural characteristics. The as‐synthesized p‐toluene sulfonic acid loaded covalent organic framework membranes (COFMs) showing the highest proton conductivity amongst all crystalline porous organic polymeric materials reported till date, as high as 7.8 x 10‐2 S cm‐1, have been further tested under real PEM operating conditions to ascertain their practical utilization as proton exchange membranes. Attainment of 24 mW cm‐2 power density, which is the highest among COFs and MOFs, highlights the possibilityof using a COF membrane over the other state‐of‐the‐art crystalline porous polymeric materials reported to date.</p>1 aBanerjee, Rahul1 aSasmal, Himadri, Sekhar1 aHarshitha, B., A.1 aBhange, Siddheshwar1 aKarak, Suvendu1 aHalder, Arjun1 aKurungot, Sreekumar  uhttp://library.ncl.res.in/content/superprotonic-conductivity-flexible-porous-covalent-organic-framework-membranes