01796nas a2200217   4500008004100000022001400041245008100055210006900136260009000205300000900295490000600304520100700310100002401317700001801341700002501359700001901384700001801403700001901421700002001440856011801460       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  uhttps://library.ncl.res.in/content/self-templated-chemically-stable-hollow-spherical-covalent-organic-framework-1