RESUMEN
Constructing heterojunction of supramolecular arrays self-assembled on metal-organic frameworks (MOFs) with elaborate charge transfer mechanisms is a promising strategy for the photocatalytic oxidation of organic pollutants. Herein, H12 SubPcB-Br (SubPc-Br) and UiO-66 are used to obtain the step-scheme (S-scheme) heterojunction SubPc-Br/UiO-66 for the first time, which is then applied in the photocatalytic oxidation of minocycline. Atomic-level B-O-Zr charge-transfer channels and van der Waals force connections synergistically accelerated the charge transfer at the interface of the SubPc-Br/UiO-66 heterojunction, while the establishment of the B-O-Zr bonds also led to the directional transfer of charge from SubPc-Br to UiO-66. The synergy is the key to improving the photocatalytic activity and stability of SubPc-Br/UiO-66, which is also verified by various characterization methods and theoretical calculations. The minocycline degradation efficiency of supramolecular SubPc-Br/UiO-66 arrays reach 90.9% within 30 min under visible light irradiation. The molecular dynamics simulations indicate that B-O-Zr bonds and van der Waals force contribute significantly to the stability of the SubPc-Br/UiO-66 heterojunction. This work reveals an approach for the rational design of semiconducting MOF-based heterojunctions with improved properties.
RESUMEN
A mild and catalyst-free sunlight induced protocol for the remote meta bromination of electron-deficient indoles is described for the first time. Herein, N-bromosaccharin is activated by sunlight irradiation. Alternately, a synergistic activation model (Sc(OTf)3 /HFIP) has also been developed for the activation of haloniums, complementary to the light induced strategy. In addition, the cascade C6-H bromination and benzylic C-H oxidation under photocatalytic conditions was also discussed. High regio-and chem-selectivity, mild reaction conditions, and scalability demonstrate great potential of the developed methods in practical applications and further functionalization.
RESUMEN
Two novel substituted subphthalocyanines have been prepared introducing m-hydroxybenzoic acid and m-hydroxyphenylacetic acid into the axial position of bromo-subphthalocyanine. The compounds have been characterized by Fourier transform infrared (FT-IR), Nuclear Magnetic Resonance (NMR) and single-crystal X-rays diffraction (XRD) methods. Their photophysical properties show that the axial substitution results into a relatively higher fluorescence quantum efficiency (ΦF=5.74 for m-hydroxybenzoic acid and 9.09 % for m-hydroxyphenylacetic acid) in comparison with that of the prototype compound, despite the almost negligible influence on the maximum absorption or the emission position. Moreover, the electrochemical behaviors show that the axial-substituted subphthalocyanines also exhibit enhanced specific capacitances of 395â F/g (m-hydroxybenzoic acid) and 362â F/g (m-hydroxyphenylacetic acid) compared with 342â F/g (the prototype) to the largest capacitance at the scan rate of 5â mV/s, and the significantly larger capacitance retentions of 83.6 % and 82.1 % versus 37.3 % upon density up to 3â A/g. These results show the potential of these axial-substituted subphthalocyanines in the use as organic photovoltaics and supercapacitors.
RESUMEN
An efficient and convenient iridium(iii) catalyzed ortho-C-H bond amidation of weakly coordinating benzamides treated with readily available sulfonyl azides as the amino source has been described. In this transformation, ionic liquids represents an ideal reaction medium, giving rise to a broad range of amidation products under mild conditions in the open air. This protocol offers moderate to excellent chemical yields, exclusive regioselectivities, and good functional group tolerance.
RESUMEN
We developed a general and sustainable approach for the regioselective deoxygenative chalcogenation of 7-azindole N-oxides; the combination of an internal oxidant and a green solvent has been used successfully for the synthesis of mono- and dichalcogenyl 7-azaindoles which are of pharmaceutical interest. The regioselectivity is tunable by the variation of the reaction conditions. I2/PEG was established as an efficient and reusable catalytic system for C-H chalcogenation. This developed methodology has great potential for practical utility, with a broad substrate scope, green reaction conditions, and operational simplicity.
RESUMEN
A phosphinic amide is introduced as a directing group for the ortho C-H alkenylation of anilines. The new donor group distinguishes itself from existing ones by assisting the C-H bond activation of anilides without (NH group) and with alkylation (NMe group) at the amide nitrogen atom. The reactivity is even reversed with the methyl-substituted anilide being more reactive than its unsubstituted counterpart. Electron-donating substituents at the arene ring enhance their reactivity while halogenation is not tolerated. The phosphinic amide also enables the C-7-selective C-H alkenylation of indoline.
RESUMEN
An improved method for the dehydrogenative C-H/C-H cross-coupling at the C-7 position of indolines containing a urea as a directing group is reported. The new protocol is a rare example of an aerobic palladium(II)-catalyzed cross dehydrogenative coupling (CDC) reaction that proceeds at low temperature. The use of either Cu(OAc)2 in an open flask or dioxygen (balloon) at 50 °C tolerates indolines not substituted at C-2 and C-3, thereby extending the scope of the previous method that suffers from indoline-to-indole oxidation.
RESUMEN
A mild procedure for C-7-selective C-H alkenylation of various indolines under oxidative palladium(II) catalysis is reported. A fully substituted urea, formed by carbamoylation of the indoline nitrogen atom, functions as a directing group. Both α,ß-unsaturated acceptors and styrenes participate in this direct C-H functionalization. With a free NH group at the urea terminus, the nitrogen atom subsequently cyclizes in a 1,4-fashion to yield a six-membered ring.