Sara Sobhani

In this research, bimetallic CdNi nanoparticles encapsulated in a magnetic spent coffee ground (Fe₃O₄@COFF/CdNi) was synthesized as a new nanocatalyst. The structural and chemical characteristics of Fe₃O₄@COFF/CdNi were comprehensively investigated using various techniques, including FT‐IR, XRD, XPS, TEM, VSM, EDS, TGA, BET, and ICP. Through XRD, XPS analysis, TEM images, and EDS mapping, the presence of CdNi nanoalloys was conclusively established. Fe₃O₄@COFF/CdNi exhibited remarkable catalytic activity for the hydrogen generation from water using iso‐propanol as a clean sacrificial agent. The high catalytic performance of Fe₃O₄@COFF/CdNi was attributed to the synergistic cooperative effect of Cd and Ni within CdNi nanoalloys. Interestingly, this process was performed for the in situ generated hydrogen from water to reduce a range of nitrobenzenes simultaneously into the corresponding anilines in high yields (93%–98%). The magnetic and hydrophilic characteristics of Fe₃O₄@COFF/CdNi facilitated its reusability over five runs. Using water as the most abundant hydrogen source, for the first time for in situ hydrogen generation–reduction of nitrobenzenes without demanding on external light sources or power supplies can be mentioned as a significant milestone of this field of study.

Conducting C–C cross-coupling reactions under convenient and mild conditions remains extremely challenging in traditional organic synthesis. In this study, ZnCo₂O₄@g-C₃N₄@Cu exhibited extraordinary photocatalytic performance as a new visible light harvesting heterogeneous copper-based photocatalyst in cyanation and Mizoroki–Heck visible-light-driven cross-coupling reactions at room temperature and in air. Surprisingly, by this method, the cyanation and Mizoroki–Heck cross-coupling reactions of various iodo-, bromo- and also the challenging chloroarenes with respectively K₄[Fe(CN)₆]·3H₂O and olefins produced promising results in a sustainable and mild media. The significant photocatalytic performance of ZnCo₂O₄@g-C₃N₄@Cu arises from the synergistic optical properties of ZnCo₂O₄, g-C₃N₄, and Cu. These components can enhance the charge carrier generation and considerably reduce the recombination rate of photogenerated electron–hole pairs. No need to use heat or additives, applying an economical and benign light source, utilizing an environmentally compatible solvent, facile and low-cost photocatalytic approach, aerial conditions, high stability and convenient recyclability of the photocatalyst are the remarkable highlights of this methodology. Moreover, this platform exhibited the ability to be performed on a large scale, which is considered an important issue in industrial and pharmaceutical use. It is worth noting that this is the first time that a heterogeneous copper-based photocatalyst has been employed in visible light-promoted cyanation reactions of aryl halides.

A new MOF (Co‐TIST) was synthesized from 2,4,6‐tris (imidazol‐1‐yl)‐1,3,5‐s‐triazine (TIST) and cobalt nitrate. TIST was prepared from the reaction of cyanuric chloride and imidazole and used as a ligand for the formation of MOF. After characterization of Co‐TIST by different methods, we have investigated the carbonyl‐Heck cross‐coupling reaction of aldehydes with aryl halides in the presence of Co‐TIST as a new heterogeneous catalyst. Various ketones were obtained in good to high yields by this method. The reactions did not require high temperature, additives, or large amounts of the catalyst. The catalyst was recycled in five consecutive runs with unimportant decrease in its catalytic activity. Notably, this is the first report of using a MOF for the carbonyl‐Heck cross‐coupling reaction of aryl halides and aldehydes.

Stable palladium (II) complexes, incorporating a double (N-benzoylthiourea) arrangement bonded to a complex heterocyclic scaffold, are used as precursors of catalytic species able to promote Suzuki–Miyaura, Mizoroki–Heck, Hiyama, Buchwald–Hartwig, Hirao and Sonogashira–Hagihara cross-coupling transformations in water. These sustainable processes are chemoselective and very versatile. The nanoparticles responsible for these catalytic reactions were analyzed and studied. Their usefulness is demonstrated after several tests and analyses. The heterogeneous character of this species in water was also confirmed.

In this study, we simulate the reductive coupling (Barbier-Grignard-type) reaction of organohalides with aldehydes using a new reusable catalyst. In this regard, bimetallic alloys of NiCo encapsulated in melamine-based dendrimers (MBD) immobilized on magnetic nanoparticles symbolized as γ-Fe₂O₃-MBD/NiCo were designed and synthesized. The structure and properties of the catalyst were studied by a variety of techniques such as Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), vibrating sample magnetometry (VSM), energy-dispersive spectrometry (EDS) mapping, and inductively coupled plasma (ICP). The presence of NiCo nanoalloys was confirmed by XRD and XPS analysis, TEM images, and EDS mapping. Various secondary alcohols were produced in good to high yields by reductive coupling of different types of aldehydes and organohalides in the presence of HCO₂K as a nonmetallic reducing agent in aqueous media catalyzed by γ-Fe₂O₃-MBD/NiCo. In these reactions, the high catalytic performance of γ-Fe₂O₃-MBD/NiCo was achieved in comparison to monometallic counterparts due to the synergistic cooperative effect of Co and Ni in the NiCo nanoalloys. Magnetic and hydrophilic properties of the catalyst facilitate the catalyst recyclability for seven runs. The reusability of γ-Fe₂O₃-MBD/NiCo, use of water as an environmentally friendly solvent, ease of processing, and absence of metal additives make this process an excellent choice for the reductive coupling reaction to produce secondary alcohols from aldehydes. This is the first report on these kinds of reactions using a reusable catalyst.

A sunlight-induced tandem air oxidation-condensation of alcohols with ortho-substituted anilines or malononitrile for the efficient synthesis of benz-imidazoles/-oxazoles/-thiazoles, or benzylidene malononitrile catalyzed by Co-isatin-Schiff-base-MIL-101(Fe) as a heterogeneous multifunctional bio-photocatalyst is reported. In these reactions, Co-isatin-Schiff-base-MIL-101(Fe) acts both as a photocatalyst, and a Lewis acid to catalyze the reaction of the in-situ formed aldehydes with o-substituted anilines or malononitrile. A significant decrease in the band gap energy and an increase in the characteristic emission of MIL-101(Fe) after functionalization with cobalt Schiff-base according to the DRS analysis and fluorescence spectrophotometry, respectively, indicate that the photocatalytic effectiveness of the catalyst is associated primarily to the synergetic influence of Fe–O cluster and Co-Schiff-base. EPR results obviously pointed out that Co-isatin-Schiff-base-MIL-101(Fe) is capable of creating ¹O₂ and O₂^⋅− as active oxygen species under visible light irradiation. Using an inexpensive catalyst, sunlight irradiation, air as a cost-effective and abundant oxidant, and a low amount of the catalyst with recoverability and durability in ethanol as a green solvent, make this methodology as an environmentally friendly process with energy-saving organic synthetic strategies. Furthermore, Co-isatin-Schiff-base-MIL-101(Fe) displays excellent photocatalytic antibacterial activity under sunlight irradiation against E. coli, S. aureus and S. pyogenes. Based on our knowledge, this is the first report of using a bio-photocatalyst for the synthesis of the target molecules.

Corrigendum: Solar light induced photocatalytic degradation of tetracycline in the presence of ZnO/NiFe2O4/Co3O4 as a new and highly efficient magnetically separable photocatalyst

In this study, a new solar light-driven magnetic heterogeneous photocatalyst, denoted as ZnO/NiFe₂O₄/Co₃O₄, is successfully prepared. FT-IR, XPS, XRD, VSM, DRS, FESEM, TEM, EDS, elemental mapping, and ICP analysis are accomplished for full characterization of this catalyst. FESEM and TEM analyses of the photocatalyt clearly affirm the formation of a hexagonal structure of ZnO (25–40 nm) and the cubic structure of NiFe₂O₄ and Co₃O₄ (10–25 nm). Furthermore, the HRTEM images of the photocatalyst verify some key lattice fringes related to the photocatalyt structure. These data are in very good agreement with XRD analysis results. According to the ICP analysis, the molar ratio of ZnO/NiFe₂O₄/Co₃O₄ composite is obtained to be 1:0.75:0.5. Moreover, magnetization measurements reveals that the ZnO/NiFe₂O₄/Co₃O₄ has a superparamagnetic behavior with saturation magnetization of 32.38 emu/g. UV-vis DRS analysis indicates that the photocatalyst has a boosted and strong light response. ZnO/NiFe₂O₄/Co₃O₄, with band gap energy of about 2.65 eV [estimated according to the Tauc plot of (αhν)²vs. hν], exhibits strong potential towards the efficacious degradation of tetracycline (TC) by natural solar light. It is supposed that the synergistic optical effects between ZnO, NiFe₂O₄, and Co₃O₄ species is responsible for the increased photocatalytic performance of this photocatalyst under the optimal conditions (photocatalyst dosage = 0.02 g L⁻¹, TC concentration = 30 mg L⁻¹, pH = 9, irradiation time = 20 min, and TC degradation efficiency = 98%). The kinetic study of this degradation process is evaluated and it is well-matched with the pseudo-first-order kinetics. Based on the radical quenching tests, it can be perceived that ^•O₂⁻ species and holes are the major contributors in such a process, whereas the ^•OH radicals identify to have no major participation. The application of this methodology is implemented in a facile and low-cost photocatalytic approach to easily degrade TC by using a very low amount of the photocatalyst under natural sunlight source in an air atmosphere. The convenient magnetic isolation and reuse of the photocatalyst, and almost complete mineralization of TC (based on TOC analysis), are surveyed too, which further highlights the operational application of the current method. Notably, this method has the preferred performance among the very few methods reported for the photocatalytic degradation of TC under natural sunlight. It is assumed that the achievements of this photocatalytic method have opened an avenue for sustainable environmental remediation of a broad range of contaminants.

In this study, ZnCo₂O₄/g-C₃N₄/Cu is synthesized as a new and highly effectual solar light-driven heterogeneous photocatalyst. The prepared photocatalyst is characterized using FT-IR, XRD, XPS, DRS, FESEM, TEM, EDS, and elemental mapping techniques. The performance of ZnCo₂O₄/g-C₃N₄/Cu is studied towards the metronidazole (MNZ) degradation under solar light irradiation. The kinetics of MNZ degradation and efficacy of the operational parameters comprising the initial MNZ amount (10–30 mg L⁻¹), photocatalyst dosage (0.005–0.05 g L⁻¹), pH (3–11), and contact time (5–30 min) on the MNZ degradation process are investigated. Surprisingly, the ZnCo₂O₄/g-C₃N₄/Cu nanocomposite presents a privileged photocatalytic performance towards the MNZ degradation under solar light irradiation. The enhanced photocatalytic activity of this photocatalyst can be ascribed to the synergistic optical effects of ZnCo₂O₄, g-C₃N₄, and Cu. The value of band gap energy for ZnCo₂O₄/g-C₃N₄/Cu is estimated to be 2.3 eV based on the Tauc plot of (αhν)² vs. hν. The radical quenching experiments confirm that the superoxide radicals and holes are the principal active species in the photocatalytic degradation of MNZ, whereas the hydroxyl radicals have no major role in such degradation. The as-prepared photocatalyst is simply isolated and recycled for at least eight runs without noticeable loss of the efficiency. Using the natural sunlight source, applying a very low amount of the photocatalyst, neutrality of the reaction medium, short reaction time, high efficiency of the degradation procedure, utilizing air as the oxidant, low operational costs, and easy to recover and reuse of the photocatalyst are the significant highlights of the present method. It is supposed that the current investigation can be a step forward in the representation of an efficacious photocatalytic system in the treatment of a wide range of contaminated aquatic environments.

A novel base-metal multifunctional nanomagnetic catalyst is prepared by the immobilization of tungstate anions onto γ-Fe₂O₃ supported with imidazolium moieties. The (γ-Fe₂O₃-Im-Py)₂WO₄ was fully characterized using FT-IR, XPS, TEM, FESEM, ICP, TGA, VSM and XRD and used as a multifunctional heterogeneous catalyst for the synthesis of 2-amino-3-cyano-4H-chromenes via a multicomponent tandem oxidation process starting from alcohols under solvent-free conditions. During this process, tungstate catalyzes the oxidation of a wide range of alcohols in the presence of TBHP as a clean source. The in-situ formed aldehydes are condensed with malononitrile and β-dicarbonyl compounds/naphthols/4-hydroxycumarin through promotion by pyridine and imidazolium moieties of the catalyst. By this method, a variety of 2-amino-3-cyano-4H-chromenes are generated in good to high yields from alcohols as inexpensive and easily available starting materials. The catalyst is recovered easily by the aid of an external magnetic field and reused in five successive runs with insignificant decreasing activity.