c-h bond activation

Upcycling plastic wastes into value-added chemicals is a promising approach to put end-of-life plastic wastes back into their ecocycle. As one of the polyesters that is used daily, polyethylene terephthalate (PET) plastic waste is employed here as the model substrate. Herein, a nickel (Ni)-based catalyst was prepared via electrochemically depositing copper (Cu) species on Ni foam (NiCu/NF). The NiCu/NF formed Cu/CuO and Ni/NiO/Ni(OH)2 core-shell structures before electrolysis and reconstructed into NiOOH and CuOOH/Cu(OH)2 active species during the ethylene glycol (EG) oxidation...

Rodents have remained a menace to humans, hence there is need to evaluate for anti-rodent activity of cheap and environment friendly control methods. This study aimed at evaluating the anti-rodenticidal activity of Thevetia (T.) peruviana fruit methanol extract. T. peruviana fruit was sampled, dried and extracted using methanol/water in the ratio of 3:1 by volume. Phytochemicals; alkaloids, phenols, flavonoids, glycosides, saponins, and tannins were determined qualitatively and quantitatively in the fruit extract...

Cross-coupling reactions represent an indispensable tool in chemical synthesis. An intriguing challenge in this field is to achieve selective cross-coupling between two precursors with similar reactivity or, to the limit, the identical molecules. Here we report an unexpected dehydrobrominative cross-coupling between 1,3,5-tris(2-bromophenyl)benzene molecules on silver surfaces. Using scanning tunneling microscopy, we examine the reaction process at the single-molecular level, quantify the selectivity of the dehydrobrominative cross-coupling, and reveal the modulation of selectivity by substrate lattice-related catalytic activity or molecular assembly effect...

C-H bond ortho-substitution reaction has always been a significant and challenging topic in organic chemistry. We proposed a synthesis method based on microwave plasma torches. High-resolution mass spectrometry was used to monitor rapid reaction products. 2-Alkylbenzimidazole can be formed through the reaction of phenylnitrenium ion and nitriles on a millisecond scale. This reaction can achieve the one-step formation of benzimidazoles from benzene ring single-substituted compounds without the addition of external oxidants or catalysts...

In this article, we present a meticulous computational study to foresee the effect of an oxygen-rich macrocycle on the reactivity for C-H activation. For this study, a widely studied nonheme Fe(IV)O molecule with a TMC (1,4,8,11-tetramethyl 1,4,8,11-tetraazacyclotetradecane) macrocycle that is equatorially attached to four nitrogen atoms (designated as N4 ) and acetonitrile as an axial ligand has been taken into account. For the goal of hetero-substitution, step-by-step replacement of the N4 framework with O atoms, i...

To meet the demand for quillaic acid, a multigram synthesis of quillaic acid was accomplished in 14 steps, starting from oleanolic acid, leading to an overall yield of 3.4%. Key features include C-H activation at C-16 and C-23. Through Pd-catalyzed C-H acetoxylation, the oxidation at C-23 was observed as the major product, as opposed to at C-24. A copper-mediated C-H hydroxylation using O2 successfully afforded the single isomer, 16β-ol triterpenoid, followed by configuration inversion to the desired 16α-ol compound...

With the increasing need for reliable storage systems, the conversion-type chemistry typified by bromine cathodes has attracted considerable attention due to sizeable theoretical capacity, cost efficiency, and high redox potential. However, the severe loss of active species during operation remains a problem, leading researchers to resort to concentrated halide-containing electrolytes. Here, profiting from the intrinsic halide exchange in perovskite lattices, we proposed a novel low-dimensional halide hybrid perovskite cathode, TmdpPb2 [IBr]6 , which served not only as a halogen reservoir for reversible three-electron conversions but also as an effective halogen absorbent by surface Pb dangling bonds, C-H…Br hydrogen bonds, and Pb-I…Br halogen bonds...

Glycine rich polyproline II helix assemblies are an emerging class of natural domains found in several proteins with different functions and diverse origins. The distinct properties of these domains relative to those composed of α-helices and β-sheets could make glycine-rich polyproline II helix assemblies a useful building block for protein design. Whereas the high population of polyproline II conformers in disordered state ensembles could facilitate glycine-rich polyproline II helix folding, the architectonic bases of these structures are not well known...

Ruthenium(II)-catalyzed synthesis of π-conjugated fused imidazo[1,5-a]quinolin-2-ium derivatives have been achieved via C-H activation of quinoline-functionalized NHC (NHC = N-heterocyclic carbene) and oxidative coupling with internal alkynes. The reaction occurred with high efficiency, broad substrate scope, tolerates a wide range of functional groups and utilized into a gram-scale. Synthetic applications of a coupled product have been exemplified in the late-stage derivatization of various highly functionalized scaffolds...

The density functional theory (DFT) was employed to theoretically investigate the reaction mechanism of alcohol deoxygenation/trifluoromethylation. The substrate alcohol ( R1 ) forms a complex ( INT3 ) by binding with benzoxazole salts ( NHCs ). Under the influence of the photocatalyst ([IrIII ]*) and quinuclidine, the C-H bond in INT3 is activated through either electron transfer-proton transfer (ETPT) or hydrogen atom transfer (HAT) mechanisms, resulting in the cleavage of C-O bonds and generation of deoxyalkyl radicals...

ConspectusZinc oxide (ZnO) is a multipurpose material and finds its applications in various fields such as rubber manufacturing, medicine, food additives, electronics, etc. It has also been intensively studied in photocatalysis due to its wide band gap and environmental compatibility. Recently, heterogeneous catalysts with supported ZnO x species have attracted more and more attention for the dehydrogenation of propane (PDH) and isobutane (iBDH) present in shale/natural gas. The olefins formed in these reactions are key building blocks of the chemical industry...

This study accessed the potential antimalarial activity of triterpene glycoside of H. atra through targeting orotidine 5-monophosphate decarboxylase protein (PfOMPDC) in P. falciparum by molecular docking. Nine triterpene glycosides from H. atra extract modeled the structure by the Corina web server and interacted with PfOMPDC protein by using Hex 8.0.0. The docking results were visualized and analyzed by Discovery Studio version 21.1.1. 17-Hydroxyfuscocineroside B showed the lowest binding energy in PfOMPDC interaction, which was -1,098...

The need for sunlight chemical renewal and contemporary organic transformation has fostered the advancement of environmentally friendly photocatalytic techniques. For the first time, we report on the novel crafting of a bright future with selenium-infused Eosin-B (Sein-E-B) nanocomposite photocatalysts in this work. The Sein-E-B nanocomposite materials were created using a hydrothermal process for solar chemical regeneration and organic transformation under visible light. The synthesized samples were subjected to UV-DRS-visible spectroscopy, FT-IR, SEM, EDX, EIS and XRD analysis...

The ionic transition metal complexes (iTMCs) [{Pt(C∧ C*)(μ-Rpz)}2 Ag(PPh3 )]X (HC∧ C* = 1-(4-(ethoxycarbonyl)phenyl)-3-methyl-1 H -imidazole-2-ylidene, X = ClO4 /PF6; Rpz = pz 1 a /2a , 4-Mepz 1 b /2b , and 3,5-dppz 1 c /2c ) were prepared from the neutral [{Pt(C∧ C*)(μ-Rpz)}2 ] (Rpz = pz A , 4-Mepz B , and 3,5-dppz C ) and fully characterized. The "Ag(PPh3 )" fragment is in between the two square-planar platinum units in an "open book" disposition and bonded through two Pt-Ag donor-acceptor bonds, as shown by X-ray diffraction (dPt-Ag ∼ 2...

Lactam rings are found in many biologically active natural products and pharmaceuticals, including important classes of antibiotics. Methods for the asymmetric synthesis of these molecules are therefore highly desirable, particularly through the selective functionalization of unreactive aliphatic C-H bonds. Here we show the development of a strategy for the asymmetric synthesis of β-, γ-, and δ-lactams via hemoprotein-catalysed intramolecular C-H amidation reaction with readily available dioxazolone reagents...

The pressing demand for propylene has spurred intensive research on the catalytic dehydrogenation of propane to produce propylene. Gallium-based catalysts are regarded as highly promising due to their exceptional dehydrogenation activity in the presence of CO2 . However, the inherent coking issue associated with high temperature reactions poses a constraint on the stability development of this process. In this study, we employed the electrospinning method to prepare a range of Ga2 O3 -Al2 O3 mixed oxide one-dimensional nanofiber catalysts with varying molar ratios for CO2 oxidative dehydrogenation of propane (CO2 -OPDH)...

Dinitrogen (N2 ) activation and functionalization through N-N bond cleavage and N-C bond formation are of great interest and importance but remain highly challenging. We report here for the first time N2 cleavage and selective multicoupling with isocyanides in a dititanium dihydride framework. The reaction of a dinitrogen dititanium dihydride complex [{(acri PNP)Ti}2 (μ-η1 :η2 -N2 )(μ-H)2 ] ( 1 ) with an excess (four or more equivalents) of p -methoxyphenyl isocyanide at room temperature gave a novel amidoamidinatoguanidinate complex [(acri PNP)Ti{NC(═NR)NC(═NR)CH2 NR}Ti(acri PNP)(CNR)] ( 2 , acri PNP = 4,5-bis(diisopropylphosphino)-2,7,9,9-tetramethyl-9 H -acridin-10-ide; R = p -MeOC6 H4 ) through N2 splitting and coupling with three isocyanide molecules...

The N, N'-(1,2-phenylene) bis (1- (4- chlorophenyl) methanimine) (CS4) was synthesized and characterized by infrared (IR), absorption (UV-vis) and NMR (1 H and 13 C) spectral analyses. The structural parameters, vibrational frequencies, potential energy and the distribution analysis (PED) were calculated by using DFT with the basis set of B3LYP/cc-pVDZ and these spectral values were compared to the experimental values. HOMO and LUMO studied were performed in order to understand the stability and biological activity of the compound...

Cross-dehydrogenative coupling of C(sp3 )-H bonds is an ideal approach for C(sp3 )-C(sp3 ) bond construction. However, conventional approaches mainly rely on a single activation mode by either stoichiometric oxidants or electrochemical oxidation, which would lead to inferior selectivity in the reaction between similar C(sp3 )-H bonds. Herein we describe our development of a paired electrocatalysis strategy to access an unconventional selectivity in the cross-dehydrogenative coupling of alcoholic α C(sp3 )-H with allylic (or benzylic) C-H bonds, which combines hydrogen evolution reaction catalysis with hydride transfer catalysis...

The present study reports an unprecedented protocol for the phosphonylation of unactivated C(sp3)-H bonds. Utilizing 1 mol % 4DPAIPN (1,2,3,5-tetrakis(diphenylamino)-4,6-dicyanobenzene) as the catalyst, satisfactory yields of γ-phosphonylated amides are obtained through a visible light-induced reaction between N-((4-cyanobenzoyl)oxy)alkanamides and 9-fluorenyl o-phenylene phosphite at room temperature. This protocol demonstrates broad substrate scope and wide functional group compatibility.