An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, Feb 1, 2021
We report the facile one-pot single-phase syntheses of silver nanoparticles stabilized by norborn... more We report the facile one-pot single-phase syntheses of silver nanoparticles stabilized by norbornene type cationic polymers. Silver nanoparticles (AgNPs) stabilized by polyguanidino oxanorbornenes (PG) at 5 and 25 kDa and polyamino oxanorbornenes (PA) at 3 and 15 kDa have been synthesized by the reduction of silver ions with NaBH 4 in aqueous solutions at ambient temperature. The four different silver nanoparticles have been characterized by UV−vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and transmission electron microscopy (TEM) for their particle size distributions. Interestingly, PG stabilizes the silver nanoparticles better than PA as evident from our spectroscopic data. Furthermore, the AgNP-PG-5K (5K = 5 kDa) was found to serve as an effective catalyst for the reduction of 4-nitrophenol to 4aminophenol in the presence of NaBH 4. The reduction has a pseudo-first-order rate constant of 5.50 × 10 −3 s −1 and an activity parameter of 1375 s −1 g −1 , which is significantly higher than other systems reported in the literature.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Pincer complexes can act as efficient catalysts for many industrially important organic transform... more Pincer complexes can act as efficient catalysts for many industrially important organic transformations under environmentally benign and mild conditions. The NNN pincer ligands have been prepared from the reactions between pyridine-2,6-dicarbonyldichloride and benzylamine or its derivatives in the presence of 4-dimethylaminopyridine (DMAP). Pd(II) complexes containing NNN pincer ligand and acetonitrile/triphenylphosphine have been synthesized and characterized by analytical, spectroscopic (FT-IR, UV-Visible, 1 H, 13 C & 31 P NMR and Mass) and single crystal X-ray diffraction techniques. Single crystal X-ray analysis reveals a distorted square planar geometry around Pd in all the complexes. These pincer complexes have been used as catalysts in Suzuki-Miyaura cross-coupling reaction. The effect of ancillary ligands (CH 3 CN and PPh 3) in the complexes has been investigated towards the coupling reaction. The conversions have been determined from GC analyses. Scope of the system has been extended with various substituted halides.
Chiral and achiral Pd(II)‐NNN pincer complexes (1–3) containing acetonitrile as an ancillary liga... more Chiral and achiral Pd(II)‐NNN pincer complexes (1–3) containing acetonitrile as an ancillary ligand were synthesized and characterized by spectroscopic (UV‐visible, FT‐IR, NMR and mass) techniques. Polarimetric experiments were employed to measure the specific rotation values of the chiral complexes {[α]D27= +135° (2) and −136° (3)}. The structures resolved through single crystal X‐ray diffraction technique disclosed the distorted square planar geometry of the complexes. Transfer hydrogenation (TH) reactions of ketones were carried out in order to appraise the catalytic efficiency of the complexes. Remarkably, the TH results were promising for all the complexes, however, the chiral complexes (2 and 3) failed to induce chirality. Further probe led us to believe that the pincer complexes turned into Pd particles in situ and the later acted as an active catalyst. The scope of TH was extended to various substituted aromatic and heterocyclic ketones (Conversions=75–99%).
The synthesized isatin thiosemicarbazone compounds (1e10) were well characterized by elemental an... more The synthesized isatin thiosemicarbazone compounds (1e10) were well characterized by elemental analysis, and UVeVisible, FT-IR and NMR spectroscopic methods. The crystal structure of two of the compounds (6 and 9) was confirmed by single crystal X-ray crystallography. Hirshfeld surface analysis was performed to analyze the intermolecular interactions. The compounds were evaluated for their in vitro antioxidant and cytotoxicity against MCF-7 (breast) cancer cell line through DPPH and MTT assays, respectively. The results clearly indicated that compounds 5, 6, 7 and 8 showed significant antioxidant property and compound 7 exhibited greater cytotoxicity than the other compounds. Antiinflammatory activity of the compounds was determined by in vitro PLA2 inhibition assay and in silico molecular docking study, which showed promising results for all the compounds.
Pd(II)‐NNN pincer complexes containing sterically hindered 2‐bromopyridine (sp2 hybridized N dono... more Pd(II)‐NNN pincer complexes containing sterically hindered 2‐bromopyridine (sp2 hybridized N donor) as ancillary ligand have been synthesized in order to compare their catalytic efficiency with the reported analogous complexes containing acetonitrile (sp hybridized N donor) ancillary ligand. The complexes have been characterized by analytical and spectroscopic techniques. Single crystal XRD reveals distorted square planar structure of complex 1. These complexes have been investigated as catalysts for the Suzuki‐Miyaura cross‐coupling (SMC) reaction. The scope is extended using various substituted aromatic/aliphatic halides. The activity of the Pd(II)‐NNN pincer complexes bearing bulky 2‐bromopyridine ancillary ligand is not higher compared to that of the complexes with acetonitrile ancillary ligand, which shows superiority of acetonitrile ancillary ligand.
The use of polyvinyl acetal (PVA) brushes is one of the most effective and prominent techniques a... more The use of polyvinyl acetal (PVA) brushes is one of the most effective and prominent techniques applied for the removal of chemical mechanical planarization (CMP) contaminants. However, the brush can be a source of defects by entrapping the abrasives inside its porous structure during brush scrubbing. In this study, the effect of brush top skin layer was extensively studied on contamination, cross-contamination, and cleaning performance by comparing brushes with and without skin layer. The presence of a dense top skin layer resulted in larger contact areas and high ceria particle adsorption on the skin layer. This leads to higher cross-contamination of the wafers during scrubbing along with high cleaning performances. Conversely, the brushes without skin layer showed lower contamination and negligible cross-contamination with a reduced cleaning performance (removal of ceria particles from oxide surface). Therefore, the role of the brush skin layer is significant and needs to be cons...
Herein, we develop an efficient and novel catalytic system, i.e. silver nanoparticles (AgNPs) inc... more Herein, we develop an efficient and novel catalytic system, i.e. silver nanoparticles (AgNPs) incorporated mesoporous silica SBA-15/copolymer hybrid material, for selective oxidation of different alcohols to aldehydes or ketones under 'mild' conditions. The copolymer of N,-N-dimethylaminoethyl methacrylate and 2-hydroxyethyl acrylate (p(DMAEMA-co-HEA)) was used to graft the surface-modified SBA-15 (MS) using free radical polymerization method. Then AgNPs were decorated on the polymer grafted SBA-15. The dual (thermal and pH) responsive behaviors of the AgNPs/p(DMAEMA-co-HEA)/MS catalyst were investigated using the dynamic light scattering technique. The lower critical solution temperature (LCST) of the copolymer was found to be approximately 30-35 • C. The catalytic activity of AgNPs/p(DMAEMA-co-HEA)/MS was investigated for the selective oxidation of different alcohols to aldehydes or ketones. The conversion of catalytic products and selectivity were calculated using gas chromatographic techniques, whereas the molecular structure of products was determined using 1 H and 13 C nuclear magnetic resonance spectroscopy. The catalyst showed improved catalytic activity toward the oxidation of alcohols to aldehydes in aqueous medium below LCST and pKa value (7-7.5) of the copolymer. The selectivity toward the corresponding aldehyde was found to be significantly high (99%). The main advantages of the hybrid catalyst as compared to existing catalysts include outstanding alcohol conversion (up to 99%), short reaction time (1 h), small necessary amount of catalyst (6 mg), and performing the catalytic conversion at room temperature using water as a solvent, which are highly beneficial for organic conversion under mild reaction conditions.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, Feb 1, 2021
We report the facile one-pot single-phase syntheses of silver nanoparticles stabilized by norborn... more We report the facile one-pot single-phase syntheses of silver nanoparticles stabilized by norbornene type cationic polymers. Silver nanoparticles (AgNPs) stabilized by polyguanidino oxanorbornenes (PG) at 5 and 25 kDa and polyamino oxanorbornenes (PA) at 3 and 15 kDa have been synthesized by the reduction of silver ions with NaBH 4 in aqueous solutions at ambient temperature. The four different silver nanoparticles have been characterized by UV−vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and transmission electron microscopy (TEM) for their particle size distributions. Interestingly, PG stabilizes the silver nanoparticles better than PA as evident from our spectroscopic data. Furthermore, the AgNP-PG-5K (5K = 5 kDa) was found to serve as an effective catalyst for the reduction of 4-nitrophenol to 4aminophenol in the presence of NaBH 4. The reduction has a pseudo-first-order rate constant of 5.50 × 10 −3 s −1 and an activity parameter of 1375 s −1 g −1 , which is significantly higher than other systems reported in the literature.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Pincer complexes can act as efficient catalysts for many industrially important organic transform... more Pincer complexes can act as efficient catalysts for many industrially important organic transformations under environmentally benign and mild conditions. The NNN pincer ligands have been prepared from the reactions between pyridine-2,6-dicarbonyldichloride and benzylamine or its derivatives in the presence of 4-dimethylaminopyridine (DMAP). Pd(II) complexes containing NNN pincer ligand and acetonitrile/triphenylphosphine have been synthesized and characterized by analytical, spectroscopic (FT-IR, UV-Visible, 1 H, 13 C & 31 P NMR and Mass) and single crystal X-ray diffraction techniques. Single crystal X-ray analysis reveals a distorted square planar geometry around Pd in all the complexes. These pincer complexes have been used as catalysts in Suzuki-Miyaura cross-coupling reaction. The effect of ancillary ligands (CH 3 CN and PPh 3) in the complexes has been investigated towards the coupling reaction. The conversions have been determined from GC analyses. Scope of the system has been extended with various substituted halides.
Chiral and achiral Pd(II)‐NNN pincer complexes (1–3) containing acetonitrile as an ancillary liga... more Chiral and achiral Pd(II)‐NNN pincer complexes (1–3) containing acetonitrile as an ancillary ligand were synthesized and characterized by spectroscopic (UV‐visible, FT‐IR, NMR and mass) techniques. Polarimetric experiments were employed to measure the specific rotation values of the chiral complexes {[α]D27= +135° (2) and −136° (3)}. The structures resolved through single crystal X‐ray diffraction technique disclosed the distorted square planar geometry of the complexes. Transfer hydrogenation (TH) reactions of ketones were carried out in order to appraise the catalytic efficiency of the complexes. Remarkably, the TH results were promising for all the complexes, however, the chiral complexes (2 and 3) failed to induce chirality. Further probe led us to believe that the pincer complexes turned into Pd particles in situ and the later acted as an active catalyst. The scope of TH was extended to various substituted aromatic and heterocyclic ketones (Conversions=75–99%).
The synthesized isatin thiosemicarbazone compounds (1e10) were well characterized by elemental an... more The synthesized isatin thiosemicarbazone compounds (1e10) were well characterized by elemental analysis, and UVeVisible, FT-IR and NMR spectroscopic methods. The crystal structure of two of the compounds (6 and 9) was confirmed by single crystal X-ray crystallography. Hirshfeld surface analysis was performed to analyze the intermolecular interactions. The compounds were evaluated for their in vitro antioxidant and cytotoxicity against MCF-7 (breast) cancer cell line through DPPH and MTT assays, respectively. The results clearly indicated that compounds 5, 6, 7 and 8 showed significant antioxidant property and compound 7 exhibited greater cytotoxicity than the other compounds. Antiinflammatory activity of the compounds was determined by in vitro PLA2 inhibition assay and in silico molecular docking study, which showed promising results for all the compounds.
Pd(II)‐NNN pincer complexes containing sterically hindered 2‐bromopyridine (sp2 hybridized N dono... more Pd(II)‐NNN pincer complexes containing sterically hindered 2‐bromopyridine (sp2 hybridized N donor) as ancillary ligand have been synthesized in order to compare their catalytic efficiency with the reported analogous complexes containing acetonitrile (sp hybridized N donor) ancillary ligand. The complexes have been characterized by analytical and spectroscopic techniques. Single crystal XRD reveals distorted square planar structure of complex 1. These complexes have been investigated as catalysts for the Suzuki‐Miyaura cross‐coupling (SMC) reaction. The scope is extended using various substituted aromatic/aliphatic halides. The activity of the Pd(II)‐NNN pincer complexes bearing bulky 2‐bromopyridine ancillary ligand is not higher compared to that of the complexes with acetonitrile ancillary ligand, which shows superiority of acetonitrile ancillary ligand.
The use of polyvinyl acetal (PVA) brushes is one of the most effective and prominent techniques a... more The use of polyvinyl acetal (PVA) brushes is one of the most effective and prominent techniques applied for the removal of chemical mechanical planarization (CMP) contaminants. However, the brush can be a source of defects by entrapping the abrasives inside its porous structure during brush scrubbing. In this study, the effect of brush top skin layer was extensively studied on contamination, cross-contamination, and cleaning performance by comparing brushes with and without skin layer. The presence of a dense top skin layer resulted in larger contact areas and high ceria particle adsorption on the skin layer. This leads to higher cross-contamination of the wafers during scrubbing along with high cleaning performances. Conversely, the brushes without skin layer showed lower contamination and negligible cross-contamination with a reduced cleaning performance (removal of ceria particles from oxide surface). Therefore, the role of the brush skin layer is significant and needs to be cons...
Herein, we develop an efficient and novel catalytic system, i.e. silver nanoparticles (AgNPs) inc... more Herein, we develop an efficient and novel catalytic system, i.e. silver nanoparticles (AgNPs) incorporated mesoporous silica SBA-15/copolymer hybrid material, for selective oxidation of different alcohols to aldehydes or ketones under 'mild' conditions. The copolymer of N,-N-dimethylaminoethyl methacrylate and 2-hydroxyethyl acrylate (p(DMAEMA-co-HEA)) was used to graft the surface-modified SBA-15 (MS) using free radical polymerization method. Then AgNPs were decorated on the polymer grafted SBA-15. The dual (thermal and pH) responsive behaviors of the AgNPs/p(DMAEMA-co-HEA)/MS catalyst were investigated using the dynamic light scattering technique. The lower critical solution temperature (LCST) of the copolymer was found to be approximately 30-35 • C. The catalytic activity of AgNPs/p(DMAEMA-co-HEA)/MS was investigated for the selective oxidation of different alcohols to aldehydes or ketones. The conversion of catalytic products and selectivity were calculated using gas chromatographic techniques, whereas the molecular structure of products was determined using 1 H and 13 C nuclear magnetic resonance spectroscopy. The catalyst showed improved catalytic activity toward the oxidation of alcohols to aldehydes in aqueous medium below LCST and pKa value (7-7.5) of the copolymer. The selectivity toward the corresponding aldehyde was found to be significantly high (99%). The main advantages of the hybrid catalyst as compared to existing catalysts include outstanding alcohol conversion (up to 99%), short reaction time (1 h), small necessary amount of catalyst (6 mg), and performing the catalytic conversion at room temperature using water as a solvent, which are highly beneficial for organic conversion under mild reaction conditions.
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