Electrocatalytic Activity of Immobilized Co(II) on Porous Graphene Aerogels

The highly‐porous graphene aerogel (GA) with BET surface area of 810 m² g^?1 and three‐dimensional structure has been successfully fabricated using the hydrothermal technique. The modified glassy carbon electrode was then prepared by casting the graphene aerogel solution followed by immersing the GA/GCE in Co⁺² solution. The results showed that graphene aerogels improved the adsorption ability of the Co (II) ions. The electrocatalysis of oxygen evolution reaction (OER) at the Co‐GA modified glassy carbon elec‐ trode (Co‐GA/GCE) has been investigated using linear sweep voltammetry (LSV) in alkaline solution. The OER was noticeably enhanced at Co‐GA/GCE, representing a negative shift in the LSV curve at the Co‐GA/GCE compared to that obtained at the bare GCE. The high electrocatalytic activity, good reproducibility and low cost of proposed electrode provides desired characteristics of a potential candi‐ date in the industrial water electrolysis process.     

Synthesis of nanomagnetic supported thiourea–copper(I) catalyst and its application in the synthesis of triazoles and benzamides

A novel nanomagnetic supported thiourea–copper(I) complex and inorganic–organic Takemoto‐like hybrid nanomagnetic catalyst was designed, and synthesized. The prepared naomagnetic catalyst was characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, energy‐dispersive X‐ray analysis, transmission and scanning electron microscopies, thermogravimetry, nitrogen adsorption/desorption, zeta potential and vibrating sample magnetometry. Furthermore, the fabricated dual‐role inorganic–organic hybrid catalyst shows a striking and robust catalytic activity for the synthesis of triazoles and benzamides through click and coupling reactions, respectively, under mild and eco‐friendly reaction conditions.     

Highly regioselective N-alkylation of benzotriazole under solvent-free conditions

An efficient, simple and solvent-free method for highly regioselective N-alkylation of benzotriazole in the presence of SiO₂, K₂CO₃ and tetrabutylammonium bromide (TBAB) under thermal and microwave conditions has been described. In this method, 1-alkyl benzotriazoles were obtained regioselectively in moderate to high yields and short reaction times.     

Synthesis,Characterization and Molecular Structure of a New Tetrameric Palladium(II) Complex Containing Schiff‐Bases Derived from AMTTO (AMTTO = 4‐amino‐6‐methyl‐1,2,4‐triazine‐thione‐5‐one)

The reactions of AMTTO = 4‐amino‐6‐methyl‐1,2,4‐triazine‐thione‐5‐one (AMTTO, 1 ) with 2‐hydroxybenzaldehyde (salicylaldehyde) and 4‐hydroxybenzaldehyde in methanol under reflux conditions led to the corresponding Schiff‐bases ( H₂L1 and H₂L2 ). The reaction of H₂L1 with palladium acetate in ethanol and additional recrystallization from toluene gave the tetrameric complex [Pd(L)]₄·2C₇H₈ ( 2 ). All compounds were characterized by infrared spectroscopy, elemental analyses as well as by X‐ray diffraction studies. Crystal data for H₂L1 at ?80 °C: space group P2₁/c with a = 1285.4(1), b = 707.7(1), c = 1348.2(1) pm, β = 109.32(1)°, Z = 4, R₁ = 0.0328, H₂L2 at ?80 °C: space group P4₃2₁2 with a = 762.5(1), b = 762.5(1), c = 4038.9(2) pm, Z = 8, R₁ = 0.025 and for 2 at ?103 °C: space group C2/c with a = 2862.5(6), b = 2847.6(6), c = 1727.8(4) pm, β = 105.18(3)°, Z = 8, R₁ = 0.0704.     

Synthesis, characterization and crystal structures of palladium(II) complexes containing neutral, one and twofold deprotonated 1,2,4-triazine species

The synthesis and characterization of three new palladium(II) complexes of 4-amino-6-ethyl-1,2,4-triazine-3-thion-5-one (AETTO, H₃L), [PdCl₂(H₃L)]·H₂O (1), [Pd₂Cl₂(H₂L)(PPh₃)₃]NO₃·2CH₃CN (2) and [Pd(HL)(PPh₃)₂] (3), are reported. All the synthesized compounds are air-stable and were characterized by elemental analyses, IR, NMR spectroscopy and mass spectrometry. In addition, the molecular structures of the complexes have been determined by X-ray single crystal diffraction. On the basis of the crystallographic data, the neutral ligand in 1 and the deprotonated ligands in 2 and 3 act as bidentate NS donors. The singly deprotonated ligand in 2 acts as a bridging agent between two metal centers in the binuclear Pd^II-complex.     

Synthesis of furo[3,2-g]chromones under microwave irradiation and their antitumor activity evaluation

A series of furo[3,2-g]chromone derivatives were synthesized via the reaction of furochromone carbaldehyde 1 with amines 3a - d and thioglycolic acid to give thiazolidinones 4a - d . The later react with benzaldehyde/thiourea or hydroxylamine and DMF-DMA in glacial acetic acid to give thiazolopyrimidines 5a - d or thiazoloisoxazoles 6a - d , respectively. Also, the synthesis of α-aminophosphonates via the one-pot reaction of 1 and amines 3a , b were trapped by dialkylphosphites 7a - c afforded the corresponding α-aminophosphonates 8a - f . Applying hexaalkyltriamidophosphites 9a , b to 1 gives alkylidenephosphorane ylides 11a , b in an open structure form. In the present investigation, the in vitro inhibition capacity of compounds ( 4a , 4c , 5b , 5c , 6b - d , 8a - f , and 11a ) was screened in three human cancer cell lines HCT-116, MCF-7, and HepG2. The anticancer activity results revealed that 8b and 8e had more potent cytotoxic inhibition activity against HCT-116 cell line; however, all the tested compounds had obviously less cytotoxic activity against MCF-7 cell line, while 5b , 5c , and 6d were potent against HepG2 cell line compared with that of doxorubicin.     

Graphitic solid core carbon nanorods grown on silica sands using electron cyclotron resonance chemical vapor deposition as a highly efficient and green sorbent for removal of phenol derivatives from water sources

In this study, graphitic solid core carbon nanorods (GSCNRs) were, for the first time, anchored to the surface of silica sands through the electron cyclotron resonance chemical vapor deposition method to provide coated silica sands as a new, low-cost, green, and efficient adsorbent for the removal of organic pollutants such as phenol and 2,4-dichlorophenol (2,4-DCP) from aqueous mediums. The characteristics of GSCNRs/SiO₂ were confirmed through Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy techniques. After the optimization of several parameters, the removal efficiency of phenol and 2,4-DCP using 1 g of adsorbent amount, the initial concentration of pollutants (10 mg/L phenol and 15 mg/L 2,4-DCP), a contact time of 10 min (phenol) and 20 min (2,4-DCP), and pH = 7 were 69 and 89%, respectively. The adsorption isotherm models of Langmuir and Freundlich, as well as pseudo-first-order and pseudo-second-order kinetic models, were examined under optimal conditions. Eventually, GSCNRs/SiO₂ was regenerated five times for the removal of phenol and 2,4-DCP. The removal efficiency of the tested contaminants from inlet raw water of a water treatment plant using the proposed adsorbent was investigated.     

Photovoltaic properties of the flavonoid-based photosensitizers: Molecular-scale perspective on the natural dye solar cells

The molecular modification and the effects of the gas and water media on the ability of some flavonoids as the photosensitizers in the natural dye-sensitized solar cells were theoretically investigated. According to the results, water increases the electrophilicity of the dyes and weakens the dye/TiO₂ coupling, prohibiting the electron injection toward TiO₂. A longer path for charge transfer and a less electron-hole overlap for dihydroxychromens elevate the electron transfer more efficient than trihydroxychromen-based flavonoids. However, the presence of water molecules within an increment in the  OH groups in the flavonoid structures improves their spectroscopic properties, which is related to decrement in the gap of the frontier molecular orbitals and increment in the oscillator strength. Also, such favorable structural effects and influence of the water medium on the polarizability and excited-state lifetime have emerged. According to the energy conversion efficiency, water is a favorable solvent for dihydroxychromen-based flavonoids. Finally, different analyses on the structural geometries, excited-state, lifetime within the kinetics, and dynamics of the photovoltaic processes were performed and discussed.     

Synthesis of Polyfunctional Aromatic Ring Systems (Phloroglucide Analogs) under Microwave Irradiation

An efficient and rapid synthesis of phloroglucide analogs under microwave irradiation is described. The solid‐phase condensation reaction of the 4‐halo‐2,6‐bis(hydroxymethyl)phenols 1a , b with other substituted phenols in the presence of ZnCl₂ afforded the target molecules in much higher yields than by classical solution‐phase synthesis and allowed us to prepare new phloroglucide analogs possessing sensitive functional groups difficult to access by established means.