Synthesis of 5-aryl-3,3′-bis-indolyl and bis-7-aza-indolyl methanone derivatives from 5-bromo-7-azaindoles via sequential methylenation using microwave irradiation, CAN oxidation, and Suzuki coupling reactions

A catalyst-free and green chemical method has been developed for the methylenation of indole and N-methyl-7-aza indoles with aqueous formaldehyde afforded respective N,N′-dimethyl-3,3′-bis-7-azaindolylmethanes under microwave irradiation in excellent yield. Subsequent oxidation of the products thus obtained, using one electron chemical oxidant CAN afforded N,N′-dimethyl-3,3′-bis-7-azaindolylmethanone derivatives in excellent yield. This resulted in methanone derivatives with halogen substitution at the aryl ring which when subjected to Suzuki coupling with aryl boronic acids furnished highly functionalized fluorescent biaryl derivatives. Plausible mechanisms, characterization including XRD, and evaluation of photophysical properties of the Suzuki coupled products are described.

A catalyst-free methylenation of 7-aza indoles under MW irradiation and CAN oxidation of methylenated products to the respective ketones are achieved. Plausible mechanisms of the reactions and photophysical properties of the products are described.

Cd(ii) coordination compounds as heterogeneous catalysts for microwave-assisted peroxidative oxidation of toluene and 1-phenylethanol

Cd(ii) compounds as catalysts towards microwave assisted peroxidative oxidation (with tert-butylhydroperoxide, TBHP) of toluene and 1-phenylethanol under heterogeneous conditions are explored.

One-dimensional networks formed via the self-assembly of anthracenedibenzoic acid with zinc(II)

Self-assembly of metal-organic coordination polymers occurs because of enthalpically favorable interactions. In the case of the bulky 4,4'-(anthracene-9,10-diyl)dibenzoic acid ligand (abdH₂), we demonstrate that the presence of numerous π-π and C-H...π interactions outweigh the formation of saturated coordination complexes with zinc, leading to the formation of a dimethylformamide (DMF) solvate, namely 4,4'-(anthracene-9,10-diyl)dibenzoic acid dimethylformamide disolvate, C₂₈H₁₈O₄·2C₃H₇NO or [(abdH₂)(DMF)₂], at low concentrations of zinc. Meanwhile, at higher zinc concentrations, the abdH₂ ligand gives rise to the nonporous one-dimensional coordination polymer catena-poly[[bis(dimethylformamide-κO)zinc(II)]-μ-4,4'-(anthracene-9,10-diyl)dibenzoato-κ²O:O'], [Zn(C₂₈H₁₆O₄)(C₃H₇NO)₂]_n or [Zn(abd)(DMF)₂]_n, when assembled in dimethylformamide, while a related compound is observed when N,N-dimethylacetamide (DMA) is used as the solvent, namely catena-poly[[[bis(N,N-dimethylacetamide-κO)zinc(II)]-μ-4,4'-(anthracene-9,10-diyl)dibenzoato-κ²O:O'] N,N-dimethylacetamide monosolvate], {[Zn(C₂₈H₁₆O₄)(C₄H₉NO)₂]·C₄H₉NO}_n or {[Zn(abd)(DMA)₂]·DMA}_n. Attempts to use other amide-based solvents did not give rise to any other assembled structures.

Catalysis and photocatalysis by metal organic frameworks

This review aims to provide different strategies employed to use MOFs as solid catalysts and photocatalysts in organic transformations.

Two 2-D multifunctional cobalt(ii) compounds: field-induced single-ion magnetism and catalytic oxidation of benzylic C–H bonds

Two 2-D multifunctional cobalt(ii) compounds were reported with both field-induced single-ion magnetism and catalytic oxidation of benzylic C–H bonds.

Visible light mediated efficient oxidative benzylic sp(3) C-H to ketone derivatives obtained under mild conditions using O2

A photooxygenation of benzylic sp(3) C-H reaction has been demonstrated using O2 mediated by visible light. This protocol provides a simple and mild route to obtain ketones from benzylic sp(3) C-H bonds. Various benzylic sp(3) C-H bonds can be transformed into the desired ketone derivatives in moderate to good yields. The (18)O2 labelling experiments demonstrated that the oxygen introduced into ketone originated from dioxygen. A plausible mechanism has been proposed accordingly.

Distance-Dependent Triplet Energy Transfer between CdSe Nanocrystals and Surface Bound Anthracene

We investigate triplet energy transfer (TET) across variable-length aromatic oligo-p-phenylene and aliphatic bridges in a covalently linked CdSe nanocrystal (NC)-bridge-anthracene hybrid system. Photon upconversion measurements in saturated 9,10-diphenylanthracene hexane solutions under air-free conditions at room temperature provided the steady-state rate of TET (ket) across this interface. For flexible transmitters, ket is similar for different lengths of aliphatic bridges, suggesting that the ligands bend backward. For the rigid phenylene spacer, triplet sensitization of anthracene transmitter molecules by CdSe NCs shows a strong distance dependence, with a Dexter damping coefficient of 0.43 ± 0.07 Å(-1). The anthracene transmitter bound closest to the NC surface gave the highest quantum yield of 14.3% for the conversion of green to violet light, the current record for a hybrid platform.

Crystal structure of 4-(4-pyridinyl)-1-naphthoic acid, C16H11NO2

C16H11NO2, triclinic, P1̅, a = 7.3496(15) Å, b = 9.3709(17) Å, c = 9.4112(16) Å, α = 104.712(6)°, β = 96.261(7)°, γ = 103.400(7)°, V = 600.1(2) Å3, Z = 2, R gt (F) = 0.0466, wR ref (F 2 ) = 0.1203, T = 299 K.

Metal-Organic Frameworks as Catalysts for Oxidation Reactions

This Concept is aimed at describing the current state of the art in metal-organic frameworks (MOFs) as heterogeneous catalysts for liquid-phase oxidations, focusing on three important substrates, namely, alkenes, alkanes and alcohols. Emphases are on the nature of active sites that have been incorporated within MOFs and on future targets to be set in this area. Thus, selective alkene epoxidation with peroxides or oxygen catalyzed by constitutional metal nodes of MOFs as active sites are still to be developed. Moreover, no noble metal-free MOF has been reported to date that can act as a general catalyst for the aerobic oxidation of primary and secondary aliphatic alcohols. In contrast, in the case of alkanes, a target should be to tune the polarity of MOF internal pores to control the outcome of the autooxidation process, resulting in the selective formation of alcohol/ketone mixtures at high conversion.

Catalytic Oxidation of Alkyl Benzene

Oxidation of benzylic C-H bonds of alkyl benzene for the synthesis of corresponding carbonyl compounds is a very important reaction for both commercial manufacturing and basic research. This paper reviews various kinds of catalysts involved in the oxidation of alkyl aromatic and their activity in various conditions and probable mechanism of action where applicable. The rate of conversion of alkyl aromatic and per cent of the yield of the corresponding products for each catalyst has been included.

Crystal structure and photoluminescence of two europium compounds with phenoxyacetic acid and 2,4,6-tri(2-pyridyl)-s-triazine

Two europium crystals with HPOA and TPTZ were prepared and the heteronuclear compound exhibits superior luminescence properties compared to the homonuclear one.

Facile fabrication of magnetically recyclable metal–organic framework nanocomposites for highly efficient and selective catalytic oxidation of benzylic C–H bonds

Chemically-bonded HKUST-1@Fe₃O₄ shows exceptional activity for the oxidation of benzylic C–H bonds.

Porous Cu–BTC silica monoliths as efficient heterogeneous catalysts for the selective oxidation of alkylbenzenes

Macro-/mesoporous silica supported Cu–BTC monoliths were in situ synthesized as efficient reusable heterogeneous catalysts for the selective oxidation from alkylbenzenes to ketones with moderate to excellent yields. The catalytic selectivity of such low-cost catalysts due to the sizes and shapes of the substrates.

A chiral mixed metal-organic framework based on a Ni(saldpen) metalloligand: synthesis, characterization and catalytic performances

A three-dimensional (3D) chiral mixed metal-organic framework [Cd4Cl(Ni-L)3(Ni-HL)(H2O)6(DMF)]·4DMF (CMOF 1) based on a new enantiopure dicarboxyl-functionalized Ni(saldpen) metalloligand Ni-H2L and a novel tetranuclear cadmium cluster [Cd4Cl(CO2)7(CO2H)] has been synthesized and characterized by elemental analyses, IR and UV-vis spectra, thermogravimetric analysis, nitrogen and carbon dioxide adsorption, powder and single-crystal X-ray diffractions. Each tetranuclear-cadmium cluster in 1 is linked by eight Ni-L ligands, and each Ni-L ligand is linked by two tetranuclear-cadmium clusters to generate a 3D framework with 1D open channels (∼1.1 × 0.9 nm(2)) along the b-axis. Based on its good stability, permanent porosity, Lewis acid sites and moderate uptake for CO2, 1 can be used as a self-supported heterogeneous catalyst for the synthesis of optically active propylene carbonate by asymmetric cycloaddition of CO2 with racemic propylene oxide under relatively mild conditions.