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Pradipta Purkayastha - One of the best experts on this subject based on the ideXlab platform.
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β-Cyclodextrin Encapsulated Coumarin 6 on Graphene Oxide Nanosheets: Impact on Ground-State Electron Transfer and Excited-State Energy Transfer.
ACS omega, 2019Co-Authors: Rajashree Banerjee, Riya Sinha, Pradipta PurkayasthaAbstract:: We report a unique phenomenon of physical adsorption of Coumarin 6-β-cyclodextrin (C6-β-CD) inclusion nanostructures on graphene oxide (GO) nanosheets, thus inducing ground-state electron transfer from the C6-β-CD composite to GO. On excitation, the C6-β-CD composite initially transfers energy to the attached GO surface and subsequently collides with similar C6-β-CD@GO adducts leading to dynamic quenching of energy. The ground-state two-electron transfer process has been confirmed by cyclic voltammetry in aqueous medium, whereas the excited-state processes were inferred from steady-state and time-resolved fluorescence spectroscopy. The concept is developed toward conceiving control over the ground-state electron transfer and excited state energy transfer from the C6-β-CD composite by the adsorbed electron accepting medium (GO in this case). The C6-β-CD composite has been prepared to isolate single C6 molecules that readily undergo microcrystal formation in aqueous medium. The results show its potential toward fabrication of energy-harvesting antenna for further applications.
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Interaction of Coumarin 6 with carbon nanotubes: Disintegration of the microcrystalline state by surfactant aggregation on the nanotube surface
Journal of Molecular Liquids, 2018Co-Authors: Rajashree Banerjee, Pradipta PurkayasthaAbstract:Abstract The laser dye Coumarin 6 (C6) readily forms microcrystals in water through π-π stacking and hence the compound loses its inherent fluorescence yield. However, the C6 molecules can be extracted from the aggregates by creating vicinal hydrophobic environment. Herein, we have used carboxylic acid derivatives of SWCNTs that could internalize the C6 microcrystals due to less microchannel polarity. Molecular C6 could be extracted from the microcrystals trapped inside the SWCNTs by inducing hydrophobicity developed by aggregating surfactants on the outer wall of the nanotube. Spectroscopic results prove the interaction and internalization of the C6 microcrystals in the SWCNT channel and disintegration by the externally adsorbed surfactants. Internalization of the C6 microcrystals has also been proved by a control experiment using solid silver nanoparticles coated with surfactant double layer.
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piecemeal rekindling of Coumarin 6 fluorescence on stepwise unfolding of protein by surfactant
Journal of Physical Chemistry B, 2017Co-Authors: Rajashree Banerjee, Pradipta PurkayasthaAbstract:Coumarin 6 (C6) briskly aggregates in water, and as a result, rapidly loses fluorescence. However, vicinal hydrophobic cavity can induce disintegration of the aggregates, and thus reviving the fluorescence. It is shown that carrier protein, such as bovine serum albumin (BSA), can disintegrate the microcrystals of C6 to smaller fragments and trap them inside the hydrophobic domain of the folded protein. This results into a 12-fold enhancement in the fluorescence signal of C6. However, on unfolding BSA by micelles, the C6 microcrystals break into single molecules by getting trapped in the micelles, and hence emission enhances by more than 100-folds.
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revival of the nearly extinct fluorescence of Coumarin 6 in water and complete transfer of energy to rhodamine 123
Soft Matter, 2017Co-Authors: Rajashree Banerjee, Pradipta PurkayasthaAbstract:The nearly extinct fluorescence of Coumarin 6 in water due to microcrystal formation is revived by micelles. Practically complete transfer of energy from Coumarin 6 to rhodamine 123 through resonance energy transfer could be achieved.
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revival enhancement and tuning of fluorescence from Coumarin 6 combination of host guest chemistry viscosity and collisional quenching
RSC Advances, 2016Co-Authors: Rajashree Banerjee, Somen Mondal, Pradipta PurkayasthaAbstract:Fluorescence from Coumarin 6 (C6), a laser dye, decreases considerably due to microcrystal formation in aqueous environments. The fluorescence yield can be effectively enhanced by applying β-cyclodextrin that revives the molecular entity of C6 through host–guest chemistry. C6-β-CD capsules form nanocubes in solution with surface projected hydroxyl groups. Increase in solvent viscosity brings the nanocubes closer following agglomeration, while keeping the molecular entity of C6 intact. This enhances the fluorescence from C6 encapsulated in β-CD nanocubes by 40%. Moreover, this emission can be tuned quantitatively by applying nanoparticles (silver in the present case) at each environmental viscosity level.
B. P. Choudhari - One of the best experts on this subject based on the ideXlab platform.
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Synthesis and antimicrobial screening of 5 H ,7 H - N -(Coumarin-6-yl)-2,8-diphenyl-5,7-dioxo-4,5,6,7-tetrahydrobenzimidazo[5,6- c ]furan and 5 H ,7 H - N -(Coumarin-6-yl)-2,8-diphenyl-5,7-dioxo-6-(7-methoxy-4-methylCoumarin-6-yl)-4,5,6,7-tetrahydro
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2020Co-Authors: B. P. Choudhari, V. V. MulwadAbstract:The Schiff bases 2a-d of 6-aminoCoumarins 1a-d on reaction with 4-benzylidene-2-phenyloxazolin-5-one in DMF and catalytic amount of pyridine afford 4-benzylidene-3-(Coumarin-6-yl)-2-phenylimidazolin-5-ones 3a-d which on further Wittig reaction yield the corresponding 4-benzylidene-3-(Coumarin-6-yl)-5-methylene-2-phenylimidazolines 4a-d. Compounds 4a-d on Diel's-Alder reaction with maleic anhydride and N-(7-methoxy-4-methylCoumarin-6-yl)maleimide separately give 5H,7H-N-(Coumarin-6-yl)-2,8-diphenyl-5,7-dioxo-4,5,6,7-tetrahydrobenzimidazo(5,6-c)furans 5a-d and 5H,7H-N-(Coumarin-6-yl)-2,8-diphenyl-5,7-dioxo-6-(7-methoxy-4-methylCoumarin-6-yl)-4,5,6,7-tetrahydrobenzimidazo(5,6-c)pyrroles 6a-d respectively. The structures of the compounds have been established on the basis of the spectral and analytical data. All the compounds 3-6a-d have been screened for their antimicrobial activities and found to exhibit significant antibacterial and antifungal activities.
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synthesis and antimicrobial screening of 5 h 7 h n Coumarin 6 yl 2 8 diphenyl 5 7 dioxo 4 5 6 7 tetrahydrobenzimidazo 5 6 c furan and 5 h 7 h n Coumarin 6 yl 2 8 diphenyl 5 7 dioxo 6 7 methoxy 4 methylCoumarin 6 yl 4 5 6 7 tetrahydro benzimidazo 5 6
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2006Co-Authors: B. P. Choudhari, V. V. MulwadAbstract:The Schiff bases 2a-d of 6-aminoCoumarins 1a-d on reaction with 4-benzylidene-2-phenyloxazolin-5-one in DMF and catalytic amount of pyridine afford 4-benzylidene-3-(Coumarin-6-yl)-2-phenylimidazolin-5-ones 3a-d which on further Wittig reaction yield the corresponding 4-benzylidene-3-(Coumarin-6-yl)-5-methylene-2-phenylimidazolines 4a-d. Compounds 4a-d on Diel's-Alder reaction with maleic anhydride and N-(7-methoxy-4-methylCoumarin-6-yl)maleimide separately give 5H,7H-N-(Coumarin-6-yl)-2,8-diphenyl-5,7-dioxo-4,5,6,7-tetrahydrobenzimidazo(5,6-c)furans 5a-d and 5H,7H-N-(Coumarin-6-yl)-2,8-diphenyl-5,7-dioxo-6-(7-methoxy-4-methylCoumarin-6-yl)-4,5,6,7-tetrahydrobenzimidazo(5,6-c)pyrroles 6a-d respectively. The structures of the compounds have been established on the basis of the spectral and analytical data. All the compounds 3-6a-d have been screened for their antimicrobial activities and found to exhibit significant antibacterial and antifungal activities.
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synthesis and antimicrobial screening of n Coumarin 6 ylamino thiazolidinone and spiro indolo thiazolidinone derivatives
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2005Co-Authors: B. P. Choudhari, Vinata V. MulwadAbstract:Condensation of N-[Coumarin-6-yl]hydrazonoarylmethanes 3a-h obtained from the condensation of the Coumarin-6-ylhydrazine hydrochloride 2a-d and aromatic aldehydes, on treatment with mercaptoacetic acid in dry 1,4-dioxane in the presence of catalytic amount of anhydrous zinc chloride yields N-[Coumarin-6-ylamino]-2-arylthiazolidin-4(H)-ones 4a-h. While, Coumarin-6-ylhydrazine hydrochloride 2a-d on condensation with isatin in situ yields corresponding 1,2-dihydro-3-[Coumarin-6-ylhydrazono]indol-2-ones 5a-d. Compound 5a-d on treatment with mercaptoacetic acid in dry 1,4-dioxane in the presence of catalytic amount of anhydrous zinc chloride affords N-[Coumarin-6-ylamino]spiro-[3H-indole-(1H,2H)-3,2-(4H)-thiazolidine]-2,4-diones 6a-d. The structures of the compounds 3, 4, and 6 have been confirmed on the basis of their spectral and analytical data. The above compounds are screened for their antimicrobial activities and have been found to exhibit significant antibacterial and antifungal activities.
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Synthesis of biologically active N-[Coumarin-6-yl]-3-methyl-5-(hydroxy/methyl/ 4-hydroxy-8-methylCoumarin-3-yl)pyrazoles and [2.3.1- ]-bicyclo-N-[Coumarin-6-yl]-1,2-diazepines
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2004Co-Authors: B. P. Choudhari, Vinata V. MulwadAbstract:6-Coumarinylhydrazine hydrochloride 1 on condensation with various active methylene compounds such as ethyl acetoacetate, acetylacetone, 3-(1,3-dioxobutyl)-4-hydroxy-8-methyl-2H-[1]-benzopyran-2-one and 1,3-cyclohexadioneseparately, yields the corressponding N-[Coumarin-6-yl]-5-hydroxy-3-methylpyrazole 3, N-[Coumarin-6-yl]-3,5-dimethyl-pyrazole 4, N-(Coumarin-6-yl)-3-methyl-5-(4-hydroxy-8-methylCoumarin-3-yl)pyrazole 5 and [2.3.1]-bicyclo-N-(Coumarin-6-yl)-4H-5,6-dihydro-1,2-diazepine 6. The structures of all the compounds have been confirmed on the basis of spectral and analytical data. All the above compounds have been screened for their antimicrobial activity and are found to possess significant antibacterial and antifungal activities.
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synthesis of biologically active n Coumarin 6 yl 3 methyl 5 hydroxy methyl 4 hydroxy 8 methylCoumarin 3 yl pyrazoles and 2 3 1 bicyclo n Coumarin 6 yl 1 2 diazepines
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2004Co-Authors: B. P. Choudhari, Vinata V. MulwadAbstract:6-Coumarinylhydrazine hydrochloride 1 on condensation with various active methylene compounds such as ethyl acetoacetate, acetylacetone, 3-(1,3-dioxobutyl)-4-hydroxy-8-methyl-2H-[1]-benzopyran-2-one and 1,3-cyclohexadioneseparately, yields the corressponding N-[Coumarin-6-yl]-5-hydroxy-3-methylpyrazole 3, N-[Coumarin-6-yl]-3,5-dimethyl-pyrazole 4, N-(Coumarin-6-yl)-3-methyl-5-(4-hydroxy-8-methylCoumarin-3-yl)pyrazole 5 and [2.3.1]-bicyclo-N-(Coumarin-6-yl)-4H-5,6-dihydro-1,2-diazepine 6. The structures of all the compounds have been confirmed on the basis of spectral and analytical data. All the above compounds have been screened for their antimicrobial activity and are found to possess significant antibacterial and antifungal activities.
Ying Zheng - One of the best experts on this subject based on the ideXlab platform.
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zebrafish a visual model to evaluate the biofate of transferrin receptor targeted 7peptide decorated Coumarin 6 micelles
ACS Applied Materials & Interfaces, 2017Co-Authors: Ye Li, Xiaoning Song, Xiang Yi, Ruibing Wang, Xueqing Wang, Ying ZhengAbstract:In the present study, the zebrafish was explored as an in vivo model to assess the biofate of transferrin receptor (TfR)-targeted Coumarin 6 (C6) micelles across various biological barriers. Three 7peptide (7pep)-decorated poly(ethylene glycol)-block-poly(e-caprolactone) micelles loaded with fluorescence Coumarin 6 (7pep–M–C6) with different ligand densities were constructed with particle sizes between 30 and 40 nm. Whole-mount immunostaining revealed that the expression level of TfR in the retina, brain, and intestine increased along with development stage. Compared to unmodified micelles, 7pep–M–C6 demonstrated higher uptake efficiency in the larval zebrafish. Preinhibition of TfR with 7pep implicated the TfR-mediated endocytosis pathway in the uptake of 7pep–M–C6. Confocal images of the larval zebrafish eye and brain showed the efficient delivery of C6 across the retinal pigment epithelial to the ganglion cell layer and the significant accumulation of C6 in all brain tissues, respectively, which platea...
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transport mechanism of Coumarin 6 nanocrystals with two particle sizes in mdckii monolayer and larval zebrafish
ACS Applied Materials & Interfaces, 2016Co-Authors: Xiaoqing Miao, Ye Li, Xueqing Wang, Ying ZhengAbstract:Nanocrystals (NCs) were utilized as oral formulations in commercial products to deliver lipophilic drug, but their transport mechanisms are not fully understood. This study aimed to explore the transport mechanism of NCs using in vitro Madin–Darby canine kidney II (MDCK II) cells and in vivo larval zebrafish models. Coumarin 6 (C6) was formulated into NCs with particle size of 67.5 ± 5.2 and 190 ± 9.2 nm. In vitro studies showed that 70 nm NCs accumulated in lysosome and endoplasmic reticulum (ER) as destinations. Lipid raft pathways mediated the endocytosis, while lipid raft, ER/Golgi, and Golgi/plasma membrane pathways were involved in exocytosis and transcytosis process. However, 200 nm NCs accumulated more in a lysosome, where lipid raft pathways were also involved in the endocytosis process. In vivo studies in larval zebrafish model further confirmed that the above network plays an important role in the absorption and distribution of C6-NCs.
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enhanced in vitro and in vivo uptake of a hydrophobic model drug Coumarin 6 in the presence of cucurbit 7 uril
MedChemComm, 2015Co-Authors: Xiaoqing Miao, Ye Li, Ying Zheng, Ian Wyman, Donal H Macartney, Ruibing WangAbstract:This report describes, for the first time, cucurbit[7]uril-assisted quantitative in vitro and in vivo uptake of a hydrophobic model drug, Coumarin-6, by both an epithelial cell model and a zebrafish model. The transcellular delivery pathway study suggested multiple mechanisms involved, including macropinocytosis, clathrin and lipid raft-mediated endocytosis/exocytosis.
Rajashree Banerjee - One of the best experts on this subject based on the ideXlab platform.
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β-Cyclodextrin Encapsulated Coumarin 6 on Graphene Oxide Nanosheets: Impact on Ground-State Electron Transfer and Excited-State Energy Transfer.
ACS omega, 2019Co-Authors: Rajashree Banerjee, Riya Sinha, Pradipta PurkayasthaAbstract:: We report a unique phenomenon of physical adsorption of Coumarin 6-β-cyclodextrin (C6-β-CD) inclusion nanostructures on graphene oxide (GO) nanosheets, thus inducing ground-state electron transfer from the C6-β-CD composite to GO. On excitation, the C6-β-CD composite initially transfers energy to the attached GO surface and subsequently collides with similar C6-β-CD@GO adducts leading to dynamic quenching of energy. The ground-state two-electron transfer process has been confirmed by cyclic voltammetry in aqueous medium, whereas the excited-state processes were inferred from steady-state and time-resolved fluorescence spectroscopy. The concept is developed toward conceiving control over the ground-state electron transfer and excited state energy transfer from the C6-β-CD composite by the adsorbed electron accepting medium (GO in this case). The C6-β-CD composite has been prepared to isolate single C6 molecules that readily undergo microcrystal formation in aqueous medium. The results show its potential toward fabrication of energy-harvesting antenna for further applications.
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Interaction of Coumarin 6 with carbon nanotubes: Disintegration of the microcrystalline state by surfactant aggregation on the nanotube surface
Journal of Molecular Liquids, 2018Co-Authors: Rajashree Banerjee, Pradipta PurkayasthaAbstract:Abstract The laser dye Coumarin 6 (C6) readily forms microcrystals in water through π-π stacking and hence the compound loses its inherent fluorescence yield. However, the C6 molecules can be extracted from the aggregates by creating vicinal hydrophobic environment. Herein, we have used carboxylic acid derivatives of SWCNTs that could internalize the C6 microcrystals due to less microchannel polarity. Molecular C6 could be extracted from the microcrystals trapped inside the SWCNTs by inducing hydrophobicity developed by aggregating surfactants on the outer wall of the nanotube. Spectroscopic results prove the interaction and internalization of the C6 microcrystals in the SWCNT channel and disintegration by the externally adsorbed surfactants. Internalization of the C6 microcrystals has also been proved by a control experiment using solid silver nanoparticles coated with surfactant double layer.
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piecemeal rekindling of Coumarin 6 fluorescence on stepwise unfolding of protein by surfactant
Journal of Physical Chemistry B, 2017Co-Authors: Rajashree Banerjee, Pradipta PurkayasthaAbstract:Coumarin 6 (C6) briskly aggregates in water, and as a result, rapidly loses fluorescence. However, vicinal hydrophobic cavity can induce disintegration of the aggregates, and thus reviving the fluorescence. It is shown that carrier protein, such as bovine serum albumin (BSA), can disintegrate the microcrystals of C6 to smaller fragments and trap them inside the hydrophobic domain of the folded protein. This results into a 12-fold enhancement in the fluorescence signal of C6. However, on unfolding BSA by micelles, the C6 microcrystals break into single molecules by getting trapped in the micelles, and hence emission enhances by more than 100-folds.
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revival of the nearly extinct fluorescence of Coumarin 6 in water and complete transfer of energy to rhodamine 123
Soft Matter, 2017Co-Authors: Rajashree Banerjee, Pradipta PurkayasthaAbstract:The nearly extinct fluorescence of Coumarin 6 in water due to microcrystal formation is revived by micelles. Practically complete transfer of energy from Coumarin 6 to rhodamine 123 through resonance energy transfer could be achieved.
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revival enhancement and tuning of fluorescence from Coumarin 6 combination of host guest chemistry viscosity and collisional quenching
RSC Advances, 2016Co-Authors: Rajashree Banerjee, Somen Mondal, Pradipta PurkayasthaAbstract:Fluorescence from Coumarin 6 (C6), a laser dye, decreases considerably due to microcrystal formation in aqueous environments. The fluorescence yield can be effectively enhanced by applying β-cyclodextrin that revives the molecular entity of C6 through host–guest chemistry. C6-β-CD capsules form nanocubes in solution with surface projected hydroxyl groups. Increase in solvent viscosity brings the nanocubes closer following agglomeration, while keeping the molecular entity of C6 intact. This enhances the fluorescence from C6 encapsulated in β-CD nanocubes by 40%. Moreover, this emission can be tuned quantitatively by applying nanoparticles (silver in the present case) at each environmental viscosity level.
Vinata V. Mulwad - One of the best experts on this subject based on the ideXlab platform.
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synthesis and antimicrobial screening of n Coumarin 6 ylamino thiazolidinone and spiro indolo thiazolidinone derivatives
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2005Co-Authors: B. P. Choudhari, Vinata V. MulwadAbstract:Condensation of N-[Coumarin-6-yl]hydrazonoarylmethanes 3a-h obtained from the condensation of the Coumarin-6-ylhydrazine hydrochloride 2a-d and aromatic aldehydes, on treatment with mercaptoacetic acid in dry 1,4-dioxane in the presence of catalytic amount of anhydrous zinc chloride yields N-[Coumarin-6-ylamino]-2-arylthiazolidin-4(H)-ones 4a-h. While, Coumarin-6-ylhydrazine hydrochloride 2a-d on condensation with isatin in situ yields corresponding 1,2-dihydro-3-[Coumarin-6-ylhydrazono]indol-2-ones 5a-d. Compound 5a-d on treatment with mercaptoacetic acid in dry 1,4-dioxane in the presence of catalytic amount of anhydrous zinc chloride affords N-[Coumarin-6-ylamino]spiro-[3H-indole-(1H,2H)-3,2-(4H)-thiazolidine]-2,4-diones 6a-d. The structures of the compounds 3, 4, and 6 have been confirmed on the basis of their spectral and analytical data. The above compounds are screened for their antimicrobial activities and have been found to exhibit significant antibacterial and antifungal activities.
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Synthesis of biologically active N-[Coumarin-6-yl]-3-methyl-5-(hydroxy/methyl/ 4-hydroxy-8-methylCoumarin-3-yl)pyrazoles and [2.3.1- ]-bicyclo-N-[Coumarin-6-yl]-1,2-diazepines
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2004Co-Authors: B. P. Choudhari, Vinata V. MulwadAbstract:6-Coumarinylhydrazine hydrochloride 1 on condensation with various active methylene compounds such as ethyl acetoacetate, acetylacetone, 3-(1,3-dioxobutyl)-4-hydroxy-8-methyl-2H-[1]-benzopyran-2-one and 1,3-cyclohexadioneseparately, yields the corressponding N-[Coumarin-6-yl]-5-hydroxy-3-methylpyrazole 3, N-[Coumarin-6-yl]-3,5-dimethyl-pyrazole 4, N-(Coumarin-6-yl)-3-methyl-5-(4-hydroxy-8-methylCoumarin-3-yl)pyrazole 5 and [2.3.1]-bicyclo-N-(Coumarin-6-yl)-4H-5,6-dihydro-1,2-diazepine 6. The structures of all the compounds have been confirmed on the basis of spectral and analytical data. All the above compounds have been screened for their antimicrobial activity and are found to possess significant antibacterial and antifungal activities.
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synthesis of biologically active n Coumarin 6 yl 3 methyl 5 hydroxy methyl 4 hydroxy 8 methylCoumarin 3 yl pyrazoles and 2 3 1 bicyclo n Coumarin 6 yl 1 2 diazepines
Indian Journal of Chemistry Section B-organic Chemistry Including Medicinal Chemistry, 2004Co-Authors: B. P. Choudhari, Vinata V. MulwadAbstract:6-Coumarinylhydrazine hydrochloride 1 on condensation with various active methylene compounds such as ethyl acetoacetate, acetylacetone, 3-(1,3-dioxobutyl)-4-hydroxy-8-methyl-2H-[1]-benzopyran-2-one and 1,3-cyclohexadioneseparately, yields the corressponding N-[Coumarin-6-yl]-5-hydroxy-3-methylpyrazole 3, N-[Coumarin-6-yl]-3,5-dimethyl-pyrazole 4, N-(Coumarin-6-yl)-3-methyl-5-(4-hydroxy-8-methylCoumarin-3-yl)pyrazole 5 and [2.3.1]-bicyclo-N-(Coumarin-6-yl)-4H-5,6-dihydro-1,2-diazepine 6. The structures of all the compounds have been confirmed on the basis of spectral and analytical data. All the above compounds have been screened for their antimicrobial activity and are found to possess significant antibacterial and antifungal activities.
