From truxenes to heterotruxenes: playing with heteroatoms and the symmetry of molecules

As a result of the modification of truxene, we can change the electronic structure or create multidimensional materials. Thus, the use of truxenes is very wide.

Reversible ketone hydrogenation and dehydrogenation for aqueous organic redox flow batteries

Aqueous redox flow batteries with organic active materials offer an environmentally benign, tunable, and safe route to large-scale energy storage. Development has been limited to a small palette of organics that are aqueous soluble and tend to display the necessary redox reversibility within the water stability window. We show how molecular engineering of fluorenone enables the alcohol electro-oxidation needed for reversible ketone hydrogenation and dehydrogenation at room temperature without the use of a catalyst. Flow batteries based on these fluorenone derivative anolytes operate efficiently and exhibit stable long-term cycling at ambient and mildly increased temperatures in a nondemanding environment. These results expand the palette to include reversible ketone to alcohol conversion but also suggest the potential for identifying other atypical organic redox couple candidates.

Bio-reduction of Graphene Oxide: Catalytic Applications of (Reduced) GO in Organic Synthesis

This work is based on various bio-reduction of graphene oxide into reduced graphene oxide and their applications in organic synthesis and group transformations. Graphene oxide, with abundant oxygencontaining functional groups on its basal plane, provides potential advantages, including excellent dispersibility in solvents and the good heterogeneous catalyst. This manuscript reviews various methods of synthesis of graphene and graphene oxide and a comparative study on their advantages and disadvantages, how to overcome disadvantages and covers extensive relevant literature review. In the last few years, investigation based on replacing the chemical reduction methods by some bio-compatible, chemical/impurity-free rGO including flash photo reductions, hydrothermal dehydration, solvothermal reduction, electrochemical approach, microwave-assisted reductions, light and radiation-induced reductions has been reported. Particularly, plant extracts have been applied significantly as an efficient reducing agent due to their huge bioavailability and low cost for bio-reduction of graphene oxide. These plant extracts mainly contain polyphenolic compounds, which readily get oxidized to the corresponding unreactive quinone form, which are the driving force for choosing them as bio-compatible catalyst. Currently, efforts are being made to develop biocompatible methods for the reduction of graphene oxide. The reduction abilities of such phytochemicals have been reported in the synthesis and stabilization of various nanoparticles viz. Ag, Au, Fe and Pd. Various part of plant extract has been applied for the green reduction of graphene oxide. Furthermore, the manuscript describes the catalytic applications of graphene oxide and reduced graphene oxide nanosheets as efficient carbo-catalysts for valuable organic transformations. Herein, important works dedicated to exploring graphene-based materials as carbocatalysts, including GO and rGO for organic synthesis including various functional group transformations, oxidation, reduction, coupling reaction and a wide number of multicomponent reactions have been highlighted. Finally, the aim of this study is to provide an outlook on future trends and perspectives for graphene-based materials in metal-free carbo-catalysis in green synthesis of various pharmaceutically important moieties.

Aerobic Oxidation of Benzylic Carbons Using a Guanidine Base

Metal-free reaction conditions featuring oxygen and 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) were employed for the selective oxidation of benzyl amines and active methylene compounds to afford various amides and ketones. Owing to the strong basicity of guanidine bases, TBD is presumed to play an important role in the cleavage of the C-H bond at the benzylic position of peroxide intermediates, which were formed by the reaction with oxygen.

Formation of Strong Basicity on Covalent Triazine Frameworks as Catalysts for the Oxidation of Methylene Compounds

Porous solid bases are increasingly attractive for applications in green chemistry and heterogeneous catalysis under relatively mild conditions. Here, covalent triazine frameworks (CTFs) were first applied as a support for the porous solid strong bases through a redox process between the base precursor KNO₃ and CTFs, leading to a relatively low calcination temperature (400 °C). As a result, porous organic frameworks possessing ordered microstructures as well as strong basic sites were successfully synthesized. The materials were characterized by X-ray diffraction, Fourier transform infrared, high-resolution transmission electron microscopy, temperature programmed desorption of CO₂, and so forth. The obtained solid bases displayed remarkable catalytic activity in the aerobic oxidation of methylene compounds, and the yield of fluorenones could reach 93.6% at 120 °C, which was nearly 3 times higher than that of the control catalyst. The current research may present a new idea for the construction of porous organic polymers with strong basicity.

Radical–radical cross coupling reactions of photo-excited fluorenones

Radical–radical cross coupling reactions of photoexcited 9-fluorenones have been accomplished for the first time, leading to the synthesis of 9-alkyl, pyrollidinyl and spiro-THF derivatives of 9-fluorenones.

Synthesis of highly nanoporous YBO3 architecture via a co-precipitation approach and tunable luminescent properties

We present a simple co-precipitation method to prepare highly nanoporous YBO(3) architecture using NaBO(3) ·  4H(2)O as a boric source and 600°C as the annealing temperature. The reaction was carried out under an aqueous condition without any organic solvent, surfactant, or catalysts. The prepared samples were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The photoluminescence of doped-nanoporous YBO(3):Eu(3+) was further investigated. It is expected that highly nanoporous YBO(3) architecture can be an ideal candidate for applications in catalysis, adsorption, and optoelectronic devices.

Large-area preparation of high-quality and uniform three-dimensional graphene networks through thermal degradation of graphene oxide-nitrocellulose composites

We demonstrate a simple method to prepare high-quality and uniform three-dimensional (3D) graphene networks through thermal degradation of graphene oxide (GO)-nitrocellulose composites over a large area. The nitrocellulose simultaneously acts as a support and aids in the reduction of GO by exothermic decomposition. The graphene networks have tunable porous morphology where the pore size can be controlled by adjusting the concentration of GO in the composite. This new technique is a very simple method to obtain 3D graphene networks and has the potential to produce 3D graphene-modified substrates for use in energy storage and conversion applications, in supporting frameworks of catalyst, and in sensors. In this report, the prepared 3D graphene networks were directly used as the electrodes of supercapacitors without using a binding agent and/or conducting additive with a high specific capacitance of 162.5 F g(-1) at 0.5 A g(-1) current density.