Recent Progress on Asymmetric Carbon- and Silica-Based Nanomaterials: From Synthetic Strategies to Their Applications

Carbon-and silica-based nanomaterials possess a set of merits including large surface area,good structural stability,diversified morphology,adjustable structure,and biocompatibility.These outstanding features make them widely applied in different fields.However,limited by the surface free energy effect,the current studies mainly focus on the symmetric structures,such as nanospheres,nanoflowers,nanowires,nanosheets,and core-shell structured composites.By comparison,the asymmetric structure with ingenious adjustability not only exhibits a larger effective surface area accompanied with more active sites,but also enables each component to work independently or corporately to harness their own merits,thus showing the unusual performances in some specific applications.The current review mainly focuses on the recent progress of design principles and synthesis methods of asymmetric carbon-and silica-based nanomaterials,and their applications in energy storage,catalysis,and biomedicine.Particularly,we provide some deep insights into their unique advantages in related fields from the perspective of materials’structure-performance relationship.Furthermore,the challenges and development prospects on the synthesis and applications of asymmetric carbon-and silica-based nanomaterials are also presented and highlighted.

Photocatalytic direct oxygen-isotopic labelings of carbonyls in ketones and aldehydes with oxygen-isotopic waters

Oxygen-isotopic labelings play important roles in identifying and understanding chemical and biological processes.Direct C=O to C=^(18)O or C=^(17)O conversion in a single step leading to labeled compounds can alleviate synthetic burdens without the need for resynthesis.Here we describe a photocatalytic oxygenisotopic labeling protocol that can efficiently and selectively install ^(18)O and ^(17)O on carbonyls of ketones and aldehydes via oxygen isotope exchange with oxygen-isotopic waters(H_(2)^(18)O or H_(2)^(17)O)as the sources of oxygen isotopes,in which light and oxygen-enabled sodium alkanesulfinates catalyzed this process.This strategy was extended to the in-situ formed ketones from the photocatalytic aerobic oxidation of alkyl arenes and secondary alcohols.Furthermore,reduction of the oxygen-isotopically labeled aldehydes with NaBH_(4) provided the corresponding oxygen-isotopically labeled primary alcohols.We believe that the oxygen-isotopically labeling method will be widely used in chemistry,biology and medicine fields.