Extended architectures constructed of thiourea‐modified SBA‐15 nanoreactor: A versatile new support for the fabrication of palladium pre‐catalyst

CCH-Pd complex anchored on ZrFe2O4 nanoparticles as a novel magnetic catalytic for C-C coupling reactions

In the present work, Palladium nanoparticles were supported on Cinchonine functionalized ZrFe2O4 MNPs. The structure, morphology, and physicochemical properties of the particles were characterized through different analytical techniques, including fourier transformed infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), inductively coupled plasma (ICP), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS) and vibrating sample magnetometer (VSM) techniques. Moreover, it was obtained as an efficient catalyst for Hiyama and Suzuki reactions under green conditions with good to excellent yields. This method has the advantages of simple methodology, high yields, easy work-up, greener conditions, and short reaction times. This catalyst was reused four times in C-C coupling reaction without loss of its catalytic activity. The reused catalyst was characterized by ICP and FT-IR techniques. Heterogeneity and stability of ZrFe2O4@SiO2-S-CCH-Pd were studied by hot filtration test and ICP analysis.

Synthesis and characterization of ZrFe2O4@SiO2@Ade-Pd as a novel, recyclable, green, and versatile catalyst for Buchwald-Hartwig and Suzuki-Miyaura cross-coupling reactions

This work presents the simple synthesis of a green and novel Palladium based magnetic nanocatalyst with effective catalytic properties and reusability. These heterogeneous catalysts were prepared by the anchoring of Pd(0) on the surface of ZrFe2O4 MNPs coated with a di-substituted adenine (Ade) compound as a green linker. The as-synthesized ZrFe2O4@SiO2@Ade-Pd MNPs were methodically characterized over different physicochemical measures like VSM, EDX, Map, SEM, TEM, ICP, and FT-IR analysis. The catalytic activity of ZrFe2O4@SiO2@Ade-Pd was carefully examined for the room-temperature Carbon-Carbon coupling reaction in acetonitrile as a solvent. It is worth noting that the synthesized solid catalyst can be easily recovered with a bar magnet and reused for five cycles without decrease of catalytic activity.

Single-pot tandem oxidative/C-H modification amidation process using ultrasmall PdNP-encapsulated porous organosilica nanotubes

Herein, we studied a single-pot method with a dual catalysis process towards the conversion of primary aromatic alcohols to amides using ultrasmall PdNPs of controlled uniform size (1.8 nm) inside hybrid mesoporous organosilica nanotubes (MO-NTs). The catalyst exhibited excellent performance in water under mild conditions and showed high stability. The catalytic activity towards the tandem oxidation of alcohols in the presence of amine salts and H2O2 to their corresponding amides without producing byproducts was evaluated, and high yields were obtained for all products. The structure of the organosilica nanotubes containing palladium nanoparticles was investigated using various characterization techniques such as XRD, TEM, BET, solid-state 29Si NMR and solid-state 13C CP MAS NMR. Catalyst recycling tests showed that the catalytic power of PdNPs@B-SNTs was preserved after 8 cycles and a slight decrease in catalyst activity was observed.

Sulourea-coordinated Pd nanocubes for NIR-responsive photothermal/H2S therapy of cancer

BACKGROUND

Photothermal therapy (PTT) frequently cause thermal resistance in tumor cells by inducing the heat shock response, limiting its therapeutic effect. Hydrogen sulfide (H2S) with appropriate concentration can reverse the Warburg effect in cancer cells. The combination of PTT with H2S gas therapy is expected to achieve synergistic tumor treatment.

METHODS

Here, sulourea (Su) is developed as a thermosensitive/hydrolysable H2S donor to be loaded into Pd nanocubes through in-depth coordination for construction of the Pd-Su nanomedicine for the first time to achieve photo-controlled H2S release, realizing the effective combination of photothermal therapy and H2S gas therapy.

RESULTS

The Pd-Su nanomedicine shows a high Su loading capacity (85 mg g-1), a high near-infrared (NIR) photothermal conversion efficiency (69.4%), and NIR-controlled H2S release by the photothermal-triggered hydrolysis of Su. The combination of photothermal heating and H2S produces a strong synergetic effect by H2S-induced inhibition of heat shock response, thereby effectively inhibiting tumor growth. Moreover, high intratumoral accumulation of the Pd-Su nanomedicine after intravenous injection also enables photothermal/photoacoustic dual-mode imaging-guided tumor treatment.

CONCLUSIONS

The proposed NIR-responsive heat/H2S release strategy provides a new approach for effective cancer therapy.

Degradation of ciprofloxacin using hematite/MOF nanocomposite as a heterogeneous Fenton-like catalyst: A comparison of composite and core-shell structures

A novel strategy was described to fabricate hematite-MOF materials with morphologies (core-shell) and (composite) as an efficient peroxymonosulfate (PMS) activator for degrading ciprofloxacin (CIP) antibiotics. First, α-Fe₂O₃ nanoparticles (NPs) with a size distribution range of 80 nm were prepared by surfactant-assisted reflux method. Then, cobalt-based metal-organic framework (ZIF-67) was grown onto the α-Fe₂O₃ NPs with ultrasonic and solvothermal method, which can control the nanostructures morphology. The physicochemical properties of these nanostructures were probed by ATR-IR, WA-XRD, FESEM, VSM, TEM, and EDS spectroscopy. The results showed that all the added CIP (20 ppm) antibiotics were completely degraded in 30 min in the α-Fe₂O₃/ZIF-67 (0.10 g/L) and PMS (0.20 g/L) system with rate constant of 0.130 min^-1. To validate the merits of the α-Fe₂O₃/ZIF-67, α-Fe₂O₃@ZIF-67 core-shell nanostructures were also applied under similar conditions. The findings demonstrated that Co/Fe species within α-Fe₂O₃/ZIF-67 composite catalyzed PMS synergistically to the formation of the OH and SO₄^- and ¹O₂ for CIP degradation. Furthermore, α-Fe₂O₃/ZIF-67 showed good recyclability enabling facile separation of the catalyst from reaction mixtures using an external magnet. The current protocol can be a useful criterion in designing various Magnetic-MOF composites with controlled morphologies for environmental remediation.

A novel strategy for stabilization of sub-nanometric Pd colloids on kryptofix functionalized MCM-41: nanoengineered material for Stille coupling transformation

The stabilization of sub-nanometric metal particles (< 1 nm) with suitable distribution remained challenging in the catalytic arena. Herein, an intelligent strategy was described to anchoring and stabilizing sub-nanometric Pd colloids with an average size of 0.88 nm onto Kryptofix 23 functionalized MCM-41. Then, the catalytic activity of Pd@Kryf/MCM-41 was developed in Stille coupling reaction with a turnover frequency (TOF) value of 247 h-1. The findings demonstrate that porous MCM-41 structure and high-affinity Kryptofix 23 ligand toward adsorption of Pd colloids has a vital role in stabilizing the sub-nanometric particles and subsequent catalytic activity. Overall, these results suggest that Pd@Kryf/MCM-41 is a greener, more suitable option for large-scale applications and provides new insights into the stabilization of sub-nanometric metal particles.