Kaushik Mallick

Polymer‐Stabilized Palladium Nanoparticles for the Chemoselective Transfer Hydrogenation of α,β‐Unsaturated Carbonyls: Single‐Step Bottom‐Up Approach

Polypyrrole stabilised palladium nanoparticles show good catalytic efficiency for the chemoselective transfer hydrogenation of α,β‐unsaturated carbonyl compounds. The catalyst is very specific and selectively hydrogenates the olefins or acetylenes only, without affecting the carbonyl moiety, with an excellent yield of products for a wide range of substrates.

Palladium–Poly(3‐aminoquinoline) Hollow‐Sphere Composite: Application in Sonogashira Coupling Reactions

We report on the use of palladium acetate for the synthesis of a palladium‐based polymer composite material as a catalyst for Sonogashira cross‐coupling reactions for aryl and heteroaryl of iodides and bromides.

Microwave assisted azide–alkyne cycloaddition reaction using polymer supported Cu(I) as a catalytic species: a solventless approach

A polymer supported copper(I) composite has been synthesized using a one-step chemical synthesis route under ambient conditions. The resultant material serves as an effective catalyst for a 1,3-dipolar cycloaddition reaction between terminal alkynes and azides to synthesize 1,2,3-triazoles with excellent yields using a microwave irradiation technique in the absence of any solvent. The composite has also been found to be an effective catalyst for the multicomponent synthesis of 1,2,3-triazoles from organic halides, sodium azide and terminal alkynes under the identical conditions as mentioned above.

Suzuki coupling reaction in the presence of polymer immobilized palladium nanoparticles: a heterogeneous catalytic pathway

An in situ method for the fabrication of a metal–polymer composite architecture using the precursors of 1,2-diaminobenzene (DAB) and potassium tetrachloropalladate (K2PdCl4) has been reported in this manuscript where palladium nanoparticles were stabilized by the poly-(1,2-diaminobenzene), pDAB, matrix. During the reaction, DAB was oxidized, which produced pDAB, on the other hand the reduction of palladium salt formed palladium nanoparticles which were found to be uniformly dispersed throughout the macromolecule matrix. The composite material was characterized by means of different techniques, such as UV-visible and infrared spectroscopy, which has contributed the information regarding the chemical structure of the polymer, whereas electron microscopy images yielded the information regarding the size and distribution of the metal particles in the polymer matrix. The composite material was successfully employed as a catalyst for the coupling of phenylboronic acid with aryl halides (Suzuki reaction) in the presence of an inorganic base under phosphine-free condition.

Gold nanoparticle within the polymer chain, a multi-functional composite material, for the electrochemical detection of dopamine and the hydrogen atom-mediated reduction of Rhodamine-B, a mechanistic approach

Polymer-stabilized gold nanoparticles have been reported using an in situ chemical synthesis route where the gold nanoparticles were uniformly dispersed throughout the macromolecular chain and formed a uniform metal–polymer composite material. The surface properties of the composite material were characterized using X-ray diffraction and X-ray photoelectron spectroscopy techniques. The electron transfer resistance (ETR) value of the resultant material was measured using electrochemical impedance spectroscopy technique. By incorporating the gold nanoparticles in the polymer matrix, the ETR value of the composite material was decreased as compared with the pure polymer and showed the efficient catalytic performance for the electrochemical recognition of dopamine. The gold–polymer composite performed as a highly efficient material for the reduction of Rhodamine-B, which suggests that the reduction process was driven by the hydrogen atom transfer mechanism and catalyzed by the gold nanoparticles.

Single step synthesis of a ‘silver–polymer hybrid material’ and its catalytic application

Conjugated polymer stabilized silver nanoparticles have been synthesized using an in situ polymerization and composite formation (IPCF) method. The optical property of the composite material was studied employing FTIR, UV-visible and fluorescence spectroscopy techniques. The electron microscopic image showed silver nanoparticles within the size range of 7–12 nm are uniformly dispersed within the polymer matrix. The as-prepared metal–polymer nanocomposites exhibited excellent catalytic activity for the reduction of 4-nitrophenolote ions. The polymer based composite material also possesses electro-sensing activity towards the enzyme-free detection of hydrogen peroxide in a very efficient and sensitive pathway.

Biophilic carbon nanotubes.

Carbon nanotubes (CNTs) have been proposed and are actively being explored as innovative multipurpose carriers for biomolecules and diagnostic applications. Their versatile physico-chemical features enable them as a carrier of several pharmaceutically relevant entities and allow them for rational design of novel nanoscale candidates for drug development. Functionalized carbon nanotubes (f-CNT) are emerging as a new family of nanovectors for the delivery of different types of therapeutic molecules. The application of CNTs in the field of carrier-mediated delivery has become possible after the recent discovery of their capacity to penetrate into the cells. CNT can be loaded with active molecules by forming stable covalent bonds or supramolecular assemblies based on noncovalent interactions. Once the cargos are carried into various cells, tissues and organs they are able to express their biological function. In this review, we will describe the potential of f-CNT as a vehicle to deliver different types of therapeutic agents into the biological species.

Single step synthesis of a polymer supported palladium composite: a potential anode catalyst for the application of methanol oxidation

Polymer supported ionic palladium has been synthesized using a single step, in situ polymerization and composite formation route from the corresponding monomer and metal salt precursors. The composite has been characterized using various optical, microscopic and surface characterization techniques. The synthesized material was successfully used as the electrocatalyst for the methanol oxidation reaction in alkaline media, suggesting a potential candidate for methanol fuel cells application. During the reaction, the in situ transformation from ionic palladium to palladium nanoparticles has been noticed and this plays a major role for the significant improvement of the oxidation process.

Carbon nitride supported copper nanoparticles: light-induced electronic effect of the support for triazole synthesis

The composite framework of graphitic carbon nitride (gCN) supported copper nanoparticle can act as a high-performance photoreactor for the synthesis of 1,2,3-triazole derivatives under light irradiation in the absence of alkaline condition. The photoactivity of gCN originates from an electron transition from the valence band to the conduction band, in the presence of photon energy, and the hot electron acts as a scavenger of the terminal proton of the alkyne molecule to facilitate the formation of copper acetanilide complex. In this study, we have performed the experiment under a different photonic environment, including dark condition, and in the presence and absence of base. A comparative study was also executed using Cu-TiO2 system, as a reference material, in the support of our proposed mechanism. The recycling performance and the photocorrosion effect of the catalyst have also been reported in this study.

Catalytic performance of the in situ synthesized palladium–polymer nanocomposite

Polymer encapsulated metallic palladium nanoparticles have been synthesized via the oxidative polymerization route using a di-amino naphthalene monomer and a palladium based metal salt. The resultant composite material was characterized by means of optical and microscopic techniques, which offered the information about the chemical structure of the polymer and also the distribution of the metal particles in the composite material. The palladium nanoparticles were homogeneously dispersed throughout the polymer which produced a uniform metal–polymer composite material. The composite material was successfully used for the hydrogenation reaction of the 4-nitrophenolate ion with the evidence of a proton coupled electron transfer (PCET) reaction mechanism. The palladium–polymer composite material was also used as an iodide sensor for the detection of the iodide ion in the presence of other interfering anionic species.