RESUMEN
An unprecedented top-down design for the preparation of melem by 1 h stirring of melamine-based g-C3N4 in 80 °C concentrated sulfuric acid (95-98%) was discovered. The melem product was formed selectively as a monomer on the gram scale without the need for controlled conditions, inert atmosphere, and a special purification technique. The as-prepared air-stable melem showed a distinctive nano rectangular prism morphology that possesses a larger surface area than the melems achieved by traditional bottom-up designs making it a promising candidate for catalysis and adsorption processes.
RESUMEN
Efficient and selective oxidation of alcohol to the corresponding carbonyl and/or nitrile was carried out by a new water-soluble melamine-based dendritic Mn(III) complex (Melamine-Mn (III)-Schiff base complex) in the presence of 2,4,6-trichloro-1,3,5-triazine (TCT) and O2 at room temperature. Also, the oxidation of amine to the corresponding nitrile with high selectivity and conversion was performed at room temperature using the current method and high amounts of turnover frequencies (TOFs) were obtained for reactions. This system was also applicable for direct preparation of oxime through oxidation of alcohol. The catalyst was characterized by Fourier-transform infrared (FTIR), ultraviolet-visible (UV-Vis), thermogravimetric analysis (TGA), energy-dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), CHN and inductively coupled plasma (ICP) analyses. Also, oxidation/reduction behavior of the catalyst was studied by cyclic voltammetry (CV). Moreover, chemoselectivity of the catalyst was discussed with various combinations. The water-soluble catalyst could be recycled from the reaction mixture and reused for several times with a very low losing in efficiency. The recovered catalyst was also investigated with various analyses. Finally, gram scale preparation of nitrile was evaluated by present method.
RESUMEN
The crystal structure of the title compound, C(14)H(12)N(2)O(4), contains four crystallographically independent mol-ecules in the asymmetric unit. All the mol-ecules have similar conformations; the dihedral angles between the aromatic rings are 33.1â (1), 33.76â (9), 31.41â (9) and 32.56â (10)°. Intra-molecular O-Hâ¯N hydrogen bonds form S(6) ring motifs in each molecule. In the crystal, there are two pairs of pseudo-inversion-related mol-ecules. Along the c axis, mol-ecules are stacked with π-π inter-actions between the 2-hy-droxy-phenyl and 4-meth-oxy-2-nitro-phenyl rings [centroid-centroid distances = 3.5441â (12)-3.7698â (12)â Å].