Synthesis of a novel palladium nano-catalyst supported on Zn-Al layered double hydroxide containing schiff base and investigation of its catalytic activity.

Bu çalışmada, paladyum nanoparçacıklarının Schiff bazı ile fonksiyonlaştırılmış Zn-Al tabakalı çift hidroksit üzerinde immobilizasyonu ile ekonomik, çevresel, nem ve havaya dayanıklı özelliklere sahip yeni bir nanokatalizör geliştirilmiştir. Pd NPs@ZnAl LDH-Sch olarak adlandırılan nanokatalizörün yapısı, FT-IR, TEM, EDS, FE-SEM, XPS, TG ve XRD dahil olmak üzere çeşitli tekniklerle karakterize edilmiştir. Pd NPs@ZnAl LDH-Sch nanokatalizörünün katalitik potansiyeli daha sonra K4[Fe(CN)6] kullanılarak çeşitli benzonitrillerin üretimi için aril halojenür siyanasyonlarında değerlendirildi. Bu testler, Pd NPs@ZnAl LDH-Sch nanokatalizörünün çeşitli fonksiyonel gruplara karşı toleranslı olduğunu ve istenen benzonitril ürünlerinin 2 saat içinde yüksek verimlerle elde edildiğini gösterdi. Sızdırmazlık testi, Pd NPs@ZnAl LDH-Sch'nin reaksiyonlarda heterojen davrandığını ortaya koydu. Heterojen tarzı nedeniyle, Pd NPs@ZnAl LDH-Sch, basit filtrasyon yoluyla kolayca geri kazanıldı ve dayanıklılığını koruyarak 11 ardışık çalışmada yeniden kullanıldı. Ayrıca sentezlenen Pd NPs@ZnAl LDH-Sch nanokatalizörünün aril halojenür siyanasyonlarında bildirilen diğer katalizörlerden daha iyi bir performans gösterdiği bulunmuştur.In this study, a newly nanocatalyst with an economical, environmental, moisture and air-stable features was developed through immobilization of palladium nanoparticles on Schiff base-functionalized Zn-Al layered double hydroxide. The structure of nanocatalyst which was named Pd NPs@ZnAl LDH-Sch was fully studied by several techniques including FT-IR, TEM, EDS, FE-SEM, XPS, TG and, XRD. The catalytic potential of Pd NPs@ZnAl LDH-Sch nanocatalyst was then evaluated in the aryl halides cyanations for the fabrication of various benzonitriles using K4[Fe(CN)6]. These tests indicated that Pd NPs@ZnAl LDH-Sch nanocatalyst was tolerant against various functional groups, and the desired benzonitrile products were acquired with good to high yields within 2 h. Leaching test revealed that Pd NPs@ZnAl LDH-Sch acts heterogeneously in the reactions. Because of its heterogeneous manner, Pd NPs@ZnAl LDH-Sch was readily recovered via simple filtration and reused up to 11 successive runs by protecting its stability/durability. Moreover, it was found that the synthesized Pd NPs@ZnAl LDH-Sch nanocatalyst shows a better performance in the aryl halide cyanations than other reported catalysts

Facile synthesis of biaryls by palladium nanoparticles adorned on kaolin/NiFe2O4 composite as a magnetically retrievable nanocatalyst

The fabrication of catalyst systems with magnetically separable has recently gained much attention because they provide economical and practical advantages in catalytic reactions. In this study, an eco-friendly, inexpensive, and magnetically retrievable novel catalyst was successfully prepared with the stabilization of palladium nanoparticles on kaolin/spinel nickel ferrite composite (Pd-kaolin/NiFe2O4). The structural and morphological characteristics of the designed Pd-kaolin/NiFe2O4 nanocatalyst were investigated by FT-IR, XRD, TG/DTG, FE-SEM, EDS, and TEM analyses. The catalytic potential of Pd-kaolin/NiFe2O4 nanocatalyst was then investigated in Suzuki cross coupling reaction, and a variety of biaryls were obtained with high reaction yields in solvent-free media in very short reaction time. Additionally, the catalytic tests demonstrated that Pd-kaolin/NiFe2O4 nanocatalyst could be isolated easily and recycled for multiple times. The study indicates that the designed Pd-kaolin/NiFe2O4 is a useful and stabile nanocatalyst for the construction of biaryls

Immobilized palladium nanoparticles on Schiff base functionalized ZnAl layered double hydroxide: A highly stable and retrievable heterogeneous nanocatalyst towards aryl halide cyanations

In this study, a new nanocatalyst system with economical, environmental, moisture, and air-stable features was developed through immobilization of Pd nanoparticles (Pd NPs) on Schiff base-functionalized Zn-Al layered double hydroxide (ZnAl LDH-Sch). The system was named as Pd NPs@ZnAl LDH-Sch, and its structure was fully authenticated with several techniques. The catalytic potential of Pd NPs@ZnAl LDH-Sch nanocatalyst was then evaluated in the aryl halide cyanations for the fabrication of various benzonitriles using K4[Fe(CN)6]. These tests indicated that Pd NPs@ZnAl LDH-Sch nanocatalyst is tolerant against various functional groups, and the desired benzonitrile products were acquired with good to high yields within 2 h. The hot filtration experiment revealed that Pd NPs@ZnAl LDH-Sch acts heterogeneously in the reactions. Because of its heterogeneous manner, Pd NPs@ZnAl LDH-Sch was readily recovered via simple filtration and reused up to 11 successive runs by protecting its stability/durability. Moreover, it was found that the synthesized Pd NPs@ZnAl LDH-Sch nanocatalyst shows a performance in the aryl halide cyanations better than other reported catalysts

Design of a palladium nanocatalyst produced from Schiff base modified dialdehyde cellulose and its application in aryl halide cyanation and reduction of nitroarenes

In this paper, a versatile heterogeneous catalyst system (Pd-DAC-Sch) based on stabilization of palladium nanoparticles on dialdehyde cellulose Schiff base (DAC-Sch) was developed and characterized thoroughly by a variety of spectroscopic (FT-IR, XRD, 13C CPMAS, and TG) and microscopic (SEM/EDS and TEM) methods. Then the prepared Pd-DAC-Sch system was evaluated as a heterogeneous nanocatalyst for aryl halide cyanation in the presence of K4[Fe(CN)6] and for reduction of nitroarenes to amines using NaBH4 in water at room temperature. Pd-DAC-Sch nanocatalyst efficiently cyanated various aryl halides by providing satisfactory reaction yields of 87–98%. Moreover, Pd-DAC-Sch catalyzed 4-nitrophenole (4-NA), 2-nitroaniline (2-NA), and 4-nitroaniline (4-NA) reductions in short reaction time. More importantly, Pd-DAC-Sch nanocatalyst was reapplied up to six successive runs by giving a yield of 86% without any important changes in its morphology and structure. This paper shows that Pd-DAC-Sch is a highly effective, reusable, chemically stable, and therefore a useful nanocatalyst

Nanoscaled reusable palladium catalyst supported on chitosan hybrid composite microcapsules reinforced with ZnO nanoparticles for Heck coupling reactions

In the present work, a novel nanocatalyst system (Pd@CS–ZnO) was developed by adorning palladium nanoparticles on the hybrid nanocomposite consisting of chitosan and ZnO nanoparticles which are designed as a suitable stabilizer. Morphological/structural features of Pd@CS–ZnO were investigated by FT-IR, TEM, SEM, XRD, BET and EDS analyses. The catalytic efficiency of Pd@CS–ZnO was then assessed as a heterogeneous nanocatalyst against Heck coupling reaction. The tests revealed that Pd@CS–ZnO was a useful nanocatalyst which can couple the reactions of various aryl halides (I, Br, Cl) with styrene. Pd@CS–ZnO nanocatalyst proved to be easily separated with filtration and reapplied for six consecutive reaction runs. Additionally, it was found that the chemical structure of Pd@CS–ZnO was maintained during recycling tests, showing that it has high chemical stability. Furthermore, the designed catalyst system offers other benefits such as (1) cost efficiency, (2) eco-friendly nature, (3) facile preparation, (4) moisture/air insensitivity, (5) easy work up, and (6) high yields

Palladium nanoparticles embedded over chitosan/γMnO2 composite hybrid microspheres as heterogeneous nanocatalyst for effective reduction of nitroarenes and organic dyes in water

Effective remediation of toxic organic pollutants such as nitroarenes and dyes from water systems is an important global issue for purification of drinking water or wastewater. Therefore, the development of effective strategies to treat these pollutants has recently become a critical and fundamental issue, and one of the most useful methodologies is to utilize heterogeneous catalysts. In this regard, a novel nano-sized heterogeneous catalyst system was designed in the present study by stabilizing palladium nanoparticles on the composite hybrid microspheres based on chitosan and γMnO2 which was developed as the stabilizer (Pd/CS/γMnO2). The morphological/structural characterization of Pd/CS/γMnO2 nanocatalyst was carried out by SEM, XRD, TEM, BET, EDS, FT-IR, and TG analyses. Then, the catalytic role of Pd/CS/γMnO2 nanocatalyst was evaluated towards catalytic reduction of some environmental pollutants such as 2-nitroaniline (2-NA), 4-nitrophenol (4-NP), 4-nitroaniline (4-NA), 4-nitro-o-phenylenediamine (4-NPD), congo red (CR), methylene blue (MB), methyl orange (MO), methyl red (MR), and rhodamine B (RhB) in water by using NaBH4 at room temperature. The tests showed that Pd/CS/MnO2 effectively and rapidly catalyzed the reduction of these pollutants and could be reused up to 8 cycles. Additionally, it was found that the catalytic activity of Pd/CS/γMnO2 nanocatalyst was superior to those of many catalysts against the same reduction reactions. This paper concludes that Pd/CS/γMnO2 nanocatalyst appears to have a high potential to serve as an effective catalyst for remediation of wastewater thanks to its facile preparation, low cost, and good catalytic activity

Design of nanostructured palladium catalyst supported by chitosan/Co3O4 microspheres and investigation of its catalytic behavior against synthesis of benzonitriles

Designing of eco-friendly, low cost, and thermally stable stabilizing/supporting agents are always desired for production of catalyst systems which provide good catalytic performance in organic reactions. In this study, a novel, green, and efficient stabilizer containing chitosan/Co3O4 microspheres (CS/Co3O4) was developed. Palladium nanoparticles (Pd NPs) were then successfully immobilized on CS/Co3O4 as a heterogeneous nanocatalyst (Pd NPs/CS/Co3O4). Characterization of the designed materials were performed by FT-IR, TEM, FE-SEM, XRD, and EDS and it was determined that Pd NPs formed as approximately 20 nm. Catalytic behavior of Pd NPs/CS/Co3O4 was investigated in the production of different substituted benzonitriles via aryl halide cyanation. Catalytic studies indicate that electron-rich or poor aromatic halides were smoothly cyanated with good reaction yields by Pd NPs/CS/Co3O4 nanocatalyst by using K4[Fe(CN)6] as the cyanating agent. Moreover, it was found that Pd NPs/CS/Co3O4 nanocatalyst provided not only good reaction yields and but also good recovery/reusability for six times in the aryl halide cyanations. This paper displays that Pd NPs/CS/Co3O4 nanocatalyst has a great catalytic and recycling potential for aryl halide cyanations

Decorated palladium nanoparticles on chitosan/delta-FeOOH microspheres: A highly active and recyclable catalyst for Suzuki coupling reaction and cyanation of aryl halides

In this study, an eco-friendly and low cost magnetic nanocomposite consisting of chitosan/delta-FeOOH microspheres (CS/delta-FeOOH) was fabricated as a stabilizer by using a simple method. Pd nanoparticles (Pd NPs) were decorated on the designed CS/delta-FeOOH , and the resulting Pd NPs@CS/delta-FeOOH microspheres were employed as a heterogeneous catalyst in the construction of biaryl and benzonitriles. Pd NPs@CS/delta-FeOOH microspheres efficiently catalyzed the conversion of aryl iodides and bromides to the desired biaryls within 3 h. Moreover, Pd NPs@CS/delta-FeOOH microspheres showed high catalytic potential against synthesis of benzonitriles by providing yields up to of 99% within 4 h. More importantly, it was proved that Pd NPs@CS/delta-FeOOH microspheres were able to be easily recycled and reused up to eight runs for both reactions. This study reveals that Pd NPs@CS/delta-FeOOH microspheres are useful and recyclable nanocatalysts, which catalyze the synthesis of biaryl and benzonitriles with good reaction yields

Facile preparation of nanostructured Pd-Sch-delta-FeOOH particles: A highly effective and easily retrievable catalyst for aryl halide cyanation and p-nitrophenol reduction

Iron based compounds are good candidates as supports to immobilize different transition metals due to their eco-friendly nature, capability of facilitating chemical modifications, inexpensiveness, high stability and easy recoverability. In this study, palladium nanoparticles (Pd NPs) were successfully stabilized on designed Schiff base modified delta-FeOOH particles as a highly effective and readily recoverable heterogeneous catalyst (Pd-Sch-delta-FeOOH nanocatalyst). The catalyst was fabricated via a facile multi-step approach without utilizing any additional reducing agents. The Pd-Sch-delta-FeOOH was characterized by Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). Characterization studies confirmed that the prepared small sized Pd NPs were spherically shaped and well dispersed on the surface of Schiff base modified delta-FeOOH. The catalytic efficiency of Pd-Sch-delta-FeOOH nanocatalyst was then tested in the preparation of benzonitriles through cyanation of aryl halides using K-4[Fe(CN)(6)] has been utilized as a cyanation agent and also reduction of p-nitrophenol (p-NP) using NaBH4 as the reducing agent. Benzonitriles were characterized using GC-MS. Catalytic studies showed that benzonitriles were obtained in good reaction yields in the presence of heterogeneous Pd-Sch-delta-FeOOH nanocatalyst (87-98%). It was found that Pd-Sch-delta-FeOOH was also a useful nanocatalyst for p-NP reduction at ambient temperature in eco-friendly media within 2 min. The reduction rate for p-NP with Pd-Sch-delta-FeOOH was measured via UV-Vis spectroscopy from 250 nm to 550 nm. Furthermore, Pd-Sch-delta-FeOOH nanocatalyst was able to remain active for six successive runs due to its recyclable/reusable nature

Supported Pd nanoparticles on micro structured chitosan-MgAl layered double hydroxide hydrogel beads as a sustainable, effective, and recyclable nanocatalyst for Heck cross-coupling reactions

In this study, a heterogeneous nano-system with sustainable, green, highly effective, and easily recoverable properties was developed through deposition of palladium nanoparticles on chitosan-MgAl layered double hydroxide hydrogel beads (CS-MgAl LDH). Full characterization of the system denoted as Pd-CS-MgAl LDH nanocatalyst was performed by various analytical techniques including FT-IR, FE-SEM, EDS, TEM, and XRD analyses. The catalytic activity of Pd-CS-MgAl LDH was then explored in Heck cross coupling reaction, and the tests confirmed that Pd-CS-MgAl LDH is an effective and useful nanocatalyst which can couple different aryl halides with yields in the range of 90–98%. Additionally, it was found that Pd-CS-MgAl LDH nanocatalyst displays higher catalytic performance compared to other reported catalysts. Moreover, Pd-CS-MgAl LDH nanocatalyst was facilely isolated and recycled for 5 successive runs without a discernible change in its performance, showing that Pd-CS-MgAl LDH has good recoverability and practical application potential