92-92-2Relevant academic research and scientific papers
A bimetallic complex containing a cyclopentadienyl-annulated imidazol-2-ylidene
Arduengo III, Anthony J.,Tapu, Daniela,Marshall, William J.
, p. 16400 - 16401 (2005)
A bimetallic carbene complex architecture that incorporates a cyclopentadienyl-annulated imidazol-2-ylidene moiety is characterized. The ligand architecture enables direct electronic interaction between the π- and σ-bonded metals. A preliminary example of aqueous Suzuki coupling employing a metallocene-fused imidazol-2-ylidene-derived catalyst is described. Copyright
Novelty in Complexity: Relationship between Small Peptides, Pd Nanoparticles, and Catalyst Characteristics
Molnár, árpád
, p. 2025 - 2027 (2015)
Bioinspired research: The Knecht group has recently developed specific peptide-capped Pd nanoparticle catalysts. The catalyst design, inspired by nature, and the complex approach with the use of varied characterization techniques is of great interest and offers new perspectives, as well as great opportunities, for the development of new catalyst materials for future sustainable developments
Peptide template effects for the synthesis and catalytic application of Pd nanoparticle networks
Jakhmola, Anshuman,Bhandari, Rohit,Pacardo, Dennis B.,Knecht, Marc R.
, p. 1522 - 1531 (2010)
Translation of nanomaterials from spherical to other shapes has demonstrated property and activity enhancement for applications ranging from optics to catalysis. Unfortunately, synthetic techniques for the controlled production of shaped nanomaterials, which can employ harsh conditions, remains challenging. In contrast, the fabrication of nanostructures using peptides has achieved the generation of functionally active materials using bio-conditions; however, these methods are typically limited to spherical materials. By merging these techniques, the biomimetic/ambient production of functional, shaped nanostructures may be achieved. Here we present the fabrication of non-spherical Pd nanostructures prepared using a peptide template. By controlling the Pd: peptide ratio, the production of at least three different Pd morphologies is possible: nanoparticles, short linear nanoribbons, and nanoparticle networks. Furthermore, all of the materials are active for Stille C-coupling catalysis using aqueous and room temperature conditions at low Pd concentrations. The results suggest that both the zerovalent Pd materials and the ligand surface structure modulate the reactivity, which may be exploitable for optimal functionality. The Royal Society of Chemistry 2010.
Pronounced effect of pore dimension of silica support on Pd-catalyzed Suzuki coupling reaction under ambient conditions
Das, Trisha,Uyama, Hiroshi,Nandi, Mahasweta
, p. 6416 - 6426 (2018)
The pore size of the mesoporous silica support is found to have an enormous effect on the reactivity of the Pd-catalysts in the Suzuki coupling reaction. Heterogeneous palladium catalysts, MCM-Pd and SBA-Pd, have been synthesized using two different types of silica supports that differ from each other in their pore dimension. The silica surfaces are grafted with aminopropyl silane groups and functionalized with tris(4-formylphenyl)amine engaging one of the formyl groups while the other two formyl groups are reacted with two 2-aminothiophenol moieties. This results in two Schiff base sites with adjacent -SH groups leading to active metal binding sites in the samples and increases the hydrophobicity of the framework. The materials have been characterized by powder X-ray diffraction, nitrogen sorption studies, transmission electron microscopy, thermal analysis, and different spectroscopic techniques. The samples are used as catalysts for Suzuki cross-coupling reactions of aryl halides with phenylboronic acid under ambient conditions. The products of the reactions are identified and estimated by 1H NMR and gas chromatography. SBA-Pd performs much better compared to MCM-Pd and a yield of up to 98% is achieved in CH3OH within 24 h of the reactions. This is attributed to the higher pore dimension of SBA-Pd that allows better interaction of the substrate molecules with the active centers on the surface of the pores.
Simple synthesis of sub-nanometer Pd clusters: High catalytic activity of Pd/PEG-PNIPAM in Suzuki reaction
Chen, Zhe,Liang, Yu,Jia, Da-Shuang,Cui, Zhi-Min,Song, Wei-Guo
, p. 651 - 657 (2017)
Ultra-small metal nanoclusters have high surface energy and abundant active sites, and therefore their catalytic activities are usually significantly higher than those of larger nanoparticles. A temperature-responsive copolymer, namely poly(ethylene glycol)-co-poly(N-isopropylacrylamide) (PEG-PNIPAM) was synthesized as the first step, and then ultra-small Pd clusters stabilized within PEG-PNIPAM copolymer micelles were formed by direct reduction. Pd nanoclusters of size less than 2 nm showed outstanding catalytic activity in the Suzuki coupling reaction. The reaction between iodobenzene and phenylboronic acid was completed in as little as 10 s (turnover frequency = 4.3 × 104 h?1). A yield of 64% was achieved in 5 min in the reaction between chlorobenzene and phenylboronic acid. The catalyst showed significant deactivation during three consecutive runs. However, this composite catalyst consisting of Pd/PEG-PNIPAM can be easily recycled based on the reversible phase transition of temperature-responsive PEG-PNIPAM. This catalyst therefore has good potential for practical applications.
Photosensitizing properties of 2,4-dichlorobenzoic acid and chlorinated biphenyl carboxylic acids, potentially key components of chromophoric dissolved organic matter
Boreen, Anne L.,McNeill, Kristopher
, p. 4113 - 4115 (2005)
2,4-Dichlorobenzoic acid and a suite of models of chlorinated biphenyl carboxylic acids were found to be efficient sensitizers of the reactive oxygen species singlet oxygen (1O2). The Royal Society of Chemistry 2005.
Exploiting localized surface binding effects to enhance the catalytic reactivity of peptide-capped nanoparticles
Coppage, Ryan,Slocik, Joseph M.,Ramezani-Dakhel, Hadi,Bedford, Nicholas M.,Heinz, Hendrik,Naik, Rajesh R.,Knecht, Marc R.
, p. 11048 - 11054 (2013)
Peptide-based methods represent new approaches to selectively produce nanostructures with potentially important functionality. Unfortunately, biocombinatorial methods can only select peptides with target affinity and not for the properties of the final material. In this work, we present evidence to demonstrate that materials-directing peptides can be controllably modified to substantially enhance particle functionality without significantly altering nanostructural morphology. To this end, modification of selected residues to vary the site-specific binding strength and biological recognition can be employed to increase the catalytic efficiency of peptide-capped Pd nanoparticles. These results represent a step toward the de novo design of materials-directing peptides that control nanoparticle structure/function relationships.
G-/C-rich oligonucleotides stabilized pd nanocatalysts for the Suzuki coupling reaction under mild conditions
Li, Wei,Fu, Yingming,Fu, Yan,Wang, Xian,Zhang, Jinli
, p. 578 - 586 (2013)
Pd nanoparticles with narrow size distributions between 1.3 and 3.3 nm are prepared using G-/C-rich oligonucleotide as the template. These DNA-Pd nanoparticles efficiently catalyze the Suzuki coupling reaction and exhibit highly catalytic activities under mild conditions, which are greatly dependent upon the particle size of Pd nanoparticles besides the DNA sequence. For the coupling reaction of iodobenzene and phenylboronic acid at 60 C in the presence of KOH, it can be achieved high TOF value of 2646 mol biphenyl (mol Pd × h)-1 over AG22-Pd and 3640 mol biphenyl (mol Pd × h) -1 over CT22-Pd. Under the optimal experimental conditions, the yield of 100 % in biphenyl is obtained with only 0.0055 mol% AG22-Pd at 60 C for 1 h in the solvent of EtOH/H2O (1:2) using Na2CO3 or K2CO3 as the base. It is illustrated that G-/C-rich oligonucleotides are promising templates to modulate easily the morphology of Pd nanoparticles in aqueous solution with high catalytic activity.
A new family of oxime palladacycles mixed with unsymmetrical phosphorus ylides; synthesis, structural, cytotoxicity and catalytic activity studies
Samiee, Sepideh,Shiralinia, Ahmadreza,Hoveizi, Elham,Gable, Robert W.
, (2019)
In the present investigation, the reactivity of an oxime-derived palladacycle [Pd{C,N–C6H4{C(Me) = NOH}-2}(μ-Cl)]2 toward various unsymmetrical phosphorus ylides has been studied. When the ylide was added to a solution of
Rapid and amenable Suzuki coupling reaction in water using microwave and conventional heating
Leadbeater, Nicholas E.,Marco, Maria
, p. 888 - 892 (2003)
It is possible to prepare biaryls in good yield very rapidy (5-10 min) on small (1 mmol) and larger (10-20 mmol) scales from aryl halides and phenylboronic acid using water as a solvent and palladium acetate as catalyst. The reaction can be performed equally well using microwave and conventional heating, showing that using these conditions probably no nonthermal microwave effects are associated with the impressive speed of the reaction.
