Facile synthesis of a new covalent organic nanosheet (CON-KEY1) based on polyamide links as an effective heterogeneous catalyst in C-C cross coupling reactions.

C-C coupling reactions represent a fundamental synthetic methodology widely employed in academic and industrial settings. Herein, we present a report on developing and synthesizing a heterogeneous catalyst that is environmentally compatible and has recycling capabilities. Furthermore, the utilization of this catalyst for C-C coupling reactions was explored. A novel amide-based CON was prepared via the reaction of a novel [2,2'-bipyridine]-5,5'-diamine (BDA) and 1,3,5-tris(4-carboxyphenyl) (TCB). TCB was activated with carbonyl diimidazole (CDI) and then reacted with BDA to synthesize favorable CON (i.e., CON-KEY1). Finally, the CON synthesized was reacted with palladium chloride ions, and the palladium-containing organocatalytic complex was decorated with the abbreviated Pd/CON-KEY1. This new heterogeneous complex was fully characterized through the required techniques, including FT-IR, EDX, XRD, TEM, SEM, ICP, TGA-DTA, N2 isotherms, and elemental mapping analysis. Computer simulation results include a multi-sheet 2D framework proposed by CON-KEY1. As a result, palladium ions were found to be arranged between the layers and on the CON surface. This heterogeneous complex functioned as a catalyst precursor in both the Suzuki-Miyaura coupling reaction of aryl boronic acids with aryl halides and the Heck reaction of aryl halides with acrylate derivatives or styrene. The desired coupling products with various functional groups were successfully attained with excellent yields of up to 98%. Simple set-up, improved yields, short reaction times, non-toxic solvents, catalyst durability, and high turnover frequency are among the distinct advantages of this synthetic method. Some other outstanding features of this catalytic system include convenient separation of catalysts and products, high yields, almost complete conversion, high selectivity, and good turnover frequency (TOF). The results show that the highest product efficiency in the reaction was achieved in the shortest possible time using Pd/CON-KEY1. Theoretical studies demonstrated the precedence of the palladium complexation with nitrogen atoms of CON-KEY1 rather than oxygen ones. Natural Bond Orbital (NBO) analysis affirmed that the system with Pd-N bonds (Eg = 0.089 eV) is more reactive with high electron conductivity compared to the Pd-O system (Eg = 0.120 eV).

Pd nanoparticles decorated on a porous Co(BDC-NH2) MOF as an effective heterogeneous catalyst for dye reduction.

Herein, a new catalytic nanocomposite [Co(BDC-NH2)-Pd NPs] composed of a Co(BDC-NH2) MOF has been developed. The catalyst was prepared by modifying the synthesized porous Co(BDC-NH2) MOF with decorated Pd nanoparticles. This nanocatalyst was used as a heterogeneous catalyst in the reductive degradation of organic dyes Rhodamine B and methyl orange with NaBH4. The kinetic and thermodynamic parameters of the reactions were evaluated. The results showed that the low catalyst content could successfully catalyze the dye reduction reaction quickly (1 min). The metal-organic frameworks unique porous morphology of the Co(BDC-NH2) MOF appears to increase dye adsorption and achieve effective dye reduction. Additionally, recyclability studies of the catalyst confirmed that it could be recovered and reused for 10 consecutive reaction cycles with negligible Pd leaching and reduction in catalytic activity.

Synthesis of a Au/Au NPs-PPy/l-CYs/ZIF-8 nanocomposite electrode for voltammetric determination of insulin in human blood.

In this work, a modified electrode named Au/Au NPs-PPy/l-CYs/ZIF-8 was designed and built and simultaneously doped into electropolymerized polypyrrole (PPy) film using cyclic voltammetry (CV). Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and CV were used to characterize the composite films. The PPy-(ZIF-8) modified Au electrode was used to determine insulin using Square-Wave Voltammetry (SWV). It was found that the prepared zeolitic imidazolate framework-8 had excellent electrocatalytic activity towards insulin oxidation due to its unique properties. The oxidation peak current of insulin hormone increased with its concentration in the range from 1.0 to 60 nM with the linear regression equation: Ipa = 0.3421C (nM) + 3.2762 (γ = 0.998). The measurement limit was estimated to be 1 nM. While the common coexisting substances showed no interference in the response of the modified electrode to insulin, the modified electrode indicated reproducible behavior and a high level of stability during the experiments. The advantages of using these nanocomposites on the surface of modified electrodes include increased stability, good interaction between the analyte and the modified electrode, conductivity, and excellent performance due to the nanometer size of the composites. As a result, it may be particularly suitable for analytical purposes.

Pd-Coordinated Salinidol-Modified Mixed MOF: An Excellent Active Center for Efficient Nitroarenes Reduction and Selective Oxidation of Alcohols.

Selective oxidation of active and inactive alcohol substrates and reduction of nitroarenes is a highly versatile conversion that remains a challenge in controlling functionality and adjustments in metal-organic frameworks (MOFs). On the other hand, it offers an attractive opportunity to expand their applications in designing the next generation of catalysts with improved performance. Herein, a novel mixed MOF consisting of supported 2-hydroxybenzamide (mixed MOF-salinidol) has been fabricated by post-synthetic modifications of mixed MOF. Subsequently, the prepared nanocomposites were modified to impart catalytic sites using palladium chloride ions mixed with MOF-salinidol/Pd (II). After successfully designing and structurally characterizing nanocomposites, we evaluated their activity in oxidizing primary and secondary alcohols using aerobic conditions with molecular oxygen and an air atmosphere. In addition, the stability of (mixed MOF-salinidol/Pd (II)) catalysts under catalytic conditions was also demonstrated by comparing the Fourier-transform infrared spectrum, scanning electron microscopy image, and ICP-OES method before and after catalysis. Based on the results, the active surface area of the synthesized nanocatalyst is large, which highlights its unique synergistic effect between post-synthetic modified MOF and Pd, and furthermore, the availability of catalytic sites from Pd, as demonstrated by outstanding catalytic activity.

Single-Electron Transmetalation: Protecting-Group-Independent Synthesis of Secondary Benzylic Alcohol Derivatives via Photoredox/Nickel Dual Catalysis.

Protecting-group-independent cross-coupling of α-alkoxyalkyl- and α-acyloxyalkyltrifluoroborates with aryl and heteroaryl bromides is achieved through application of photoredox/nickel dual catalysis. Reactions occur under exceptionally mild conditions, with outstanding functional group compatibility and excellent observed tolerance of heteroarenes. This method offers expedient access to protected secondary benzylic alcohol motifs bearing benzyl, pivaloyl, and N,N-diisopropylcarbamoyl protecting groups.

One-pot synthesis of tetrazolo[1,5-a]pyrimidines under solvent-free conditions.

A series of 5,7-diaryl-4,7-dihydrotetrazolo [1,5-a]pyrimidines and 5-methyl-7-aryl-4,7-dihydrotetrazolo [1,5-a]pyrimidine-6-carboxylates were obtained from aryl aldehydes, 2-aminotetrazole, substituted acetophenones, or ethyl acetoacetate in good to excellent yields by proceeding through a simple, mild, and efficient procedure utilizing N,N,N,N-tetrabromobenzene-1,3-disulfonamide as catalyst.

N, N, N', N'-Tetrabromobenzene-1,3-disulfonamide and poly (N-bromo-N-ethylbenzene-1,3-disulfonamide) as new and efficient catalysts for the synthesis of highly substituted 1,6-dihydropyrazine-2,3-dicarbonitrile derivatives.

Various mono and bis-1,6-dihydropyrazine-2,3-dicarbonitrile derivatives were efficiently synthesized by reacting 2,3-diaminomaleonitrile (DAMN), isocyanides and ketones in the presence of a catalytic amount of N, N, N ,N-tetrabromobenzene-1,3-disulfonamide [TBBDA] and poly(N-bromo-N-ethylbenzene-1,3-disulfonamide) [PBBS] in EtOH/H2O at ambient temperature.