@article { ISI:000240352900023, title = {Ossification: a new approach to immobilize metal complex catalysts - applications to carbonylation and Suzuki coupling reactions}, journal = {Journal of Catalysis}, volume = {242}, number = {1}, year = {2006}, month = {AUG}, pages = {231-238}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, type = {Article}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

A simple approach for immobilization of transition metal complexes is reported here based on the transformation of the complex into its intrinsically insoluble counterpart, thus generating solid molecular catalysts. This approach that we call {\textquoteleft}{\textquoteleft}ossification{\textquoteright}{\textquoteright} is based on a principle, in which the water-soluble analogues of the metal complexes are precipitated out from aqueous solutions as insoluble ionic ensembles having catalytically active metal-centered coordination environments and robust framework. The approach has been illustrated for I{\textquoteright}d complex catalyzed carbonylation and Suzuki coupling reactions. {\textquoteleft}{\textquoteleft}Ossification{\textquoteright}{\textquoteright} was found to be an economically and environmentally attractive alternative to other exotic immobilization methodologies. (c) 2006 Elsevier Inc. All rights reserved.

}, keywords = {Carbonylation, Heterogeneous catalysts, Immobilization, ossification, Palladium complex, Suzuki coupling}, issn = {0021-9517}, doi = {10.1016/j.jcat.2006.05.032}, author = {Sarkar, Bibhas R. and Chaudhari, Raghunath V.} } @article { ISI:000267625000020, title = {Hydroesterification of 2-vinyl-6-methoxynaphthalene using palladium complexes containing chelating nitrogen ligands}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {307}, number = {1-2}, year = {2009}, month = {JUL}, pages = {134-141}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Hydroesterification of 2-vinyl-6-methoxynaphthalene (VMN) to methyl ester of 6-methoxy naphthyl propionic acid (ester of naproxen) has been investigated using palladium complexes containing the chelating N(boolean AND)O and N(boolean AND)N ligands (pyridine-2-carboxylate, 2-acetylpyridine, 2-pyridine-carboxaldehyde, and bipyridine) as catalysts. Palladium complex containing 2-acetylpyridine as the ligand was found to be superior to other Pd-complexes. Both acid and halide promoters were necessary for high activity and selectivity. As an acid promoter, benzenesulfonic acid was found to be more effective compared to p-toluenesulfonic acid. Formation of ether 2-methoxy-6-(1-methoxyethyl)naphthalene and a polymer of VMN was observed in all the reactions. It was observed that active catalytic species generated during carbonylation reaction was responsible for the polymer formation. The effect of various parameters such as solvents, CO pressure, and alcohols on the catalytic activity as well as the selectivity was investigated. The turnover frequency using the complex Pd(acpy)(PPh(3))(OTs)(2) (acpy = 2-acetylpyridine) catalyst was found to be 42 h(-1), which is the highest for the hydroesterification of VMN. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {Carbonylation, Hydroesterification, Naproxen, Palladium complex, Polymer of VMN, Promoters}, issn = {1381-1169}, doi = {10.1016/j.molcata.2009.03.021}, author = {Atla, Shashi B. and Kelkar, Ashutosh A. and Chaudhari, Raghunath V.} } @article { ISI:000311350000022, title = {Anchored Pd-complexes in mesoporous supports: synthesis, characterization and catalysis studies for carbonylation reactions}, journal = {Catalysis Today}, volume = {198}, number = {1, SI}, year = {2012}, month = {DEC}, pages = {154-173}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Pd(pyca)(PPh3)(OTs) [pyca = 2-picolinate] complex is efficiently anchored inside different mesoporous matrices, such as MCM-41, MCM-48, SBA-15 using a molecular aminopropyl tether moiety employing different synthesis strategies. Thorough characterization of the materials using powder XRD, multinuclear (C-13, Si-29, P-31) CP-MAS NMR, XPS, SEM, N-2-sorption studies etc. confirmed the successful anchoring of the palladium complex to the walls of the support matrices thus establishing the synthesis protocols unambiguously. The catalysts were found to be highly active and selective for the carbonylation of different aryl olefins and alcohols. Consecutive recycling and successful reuse proved the stability and true heterogeneous nature of all the anchored catalysts, which is a substantial advancement over the existing heterogeneous catalysts for carbonylation. (C) 2012 Elsevier B. V. All rights reserved.

}, keywords = {Anchored catalysts, Carbonylation, Immobilization, mesoporous materials, Palladium complex}, issn = {0920-5861}, doi = {10.1016/j.cattod.2012.04.047}, author = {Sarkar, Bibhas R. and Chaudhari, Raghunath V.} } @article {48808, title = {Inhibition of amyloid β1-42 peptide aggregation by newly designed cyclometallated palladium complexes}, journal = {International Journal of Biological Macromolecules}, volume = {248}, year = {2023}, month = {SEP }, pages = {125847}, type = {Article}, abstract = {

Uncontrolled amyloid aggregation is a frequent cause of neurodegenerative disorders such as prions and Alzheimer{\textquoteright}s disease (AD). As a result, many drug development approaches focus on evaluating novel molecules that can alter self-recognition pathways. Herein, we designed and synthesized the cyclometallated pyrene (Pd-1 and Pd-3) and anthracene (Pd-2) based palladium complexes ([Pd((L-1)Cl] Pd-1, [Pd(L-2)Cl](Pd-2), and [Pd(L-3)Cl] (Pd-3)). This study explores the effect of these complexes on the aggregation, fibrillation, and amyloid formation of bovine serum albumin (BSA) and A beta(1-42) peptide. Several spectroscopic methods were used to characterize all the Pd-complexes, and the molecular structure of Pd -3 was determined by X-ray crystallography. The secondary structures were studied using circular dichroism (CD) and transmission electron microscopy (TEM), while am-yloid aggregation and inhibitory activities were investigated using the Thioflavin-T (ThT) fluorescence assay. Molecular docking of the Pd-complex (Pd-3) was done using fibril (PDB: 2BEG) and monomeric (PDB: 1IYT) peptides using Auto-dock Vina. As a result, the hydrogen bonding and hydrophobic interaction between the aromatic rings of the Pd-complexes and the amino acids of amyloid-beta peptides significantly reduced the pro-duction of ordered beta-sheets of amyloid fibrils and protein aggregation in the presence of Pd-2 and Pd-3 complexes.

}, keywords = {A beta(1-42) peptide, Aggregation and molecular docking, Palladium complex}, issn = {0141-8130}, doi = {10.1016/j.ijbiomac.2023.125847}, author = {Saini, Rahul and Navale, Govinda R. and Singh, Sain and Singh, Haobam Kisan and Chauhan, Rahul and Agrawal, Sonia and Sarkar, Dhiman and Sarma, Manabendra and Ghosh, Kaushik} }