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Your search keyword '"Bhandary, Subhrajyoti"' showing total 35 results
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35 results on '"Bhandary, Subhrajyoti"'

3. Modular Synthesis of Azines Bearing a Guanidine Core from N‐Heterocyclic Carbene (NHC)‐Derived Selenoureas and Diazo Reagents.

Author

Tonis, Efstathios, Tzouras, Nikolaos V., Bracho Pozsoni, Nestor, Saab, Marina, Bhandary, Subhrajyoti, Van Hecke, Kristof, Nelson, David J., Nahra, Fady, Nolan, Steven P., and Vougioukalakis, Georgios C.

Subjects
DIAZO compounds, COORDINATE covalent bond, DENSITY functional theory, ORGANIC synthesis, GUANIDINE, AZINES
Abstract

N‐Heterocyclic carbene (NHC)‐derived selenoureas comprise a fundamentally important class of NHC derivatives, with key applications in coordination chemistry and the determination of NHC electronic properties. Considering the broad reactivity of chalcogen‐containing compounds, it is surprising to note that the use of NHC‐derived selenoureas as organic synthons remains essentially unexplored. The present contribution introduces a novel, straightforward transformation leading to azines bearing a guanidine moiety, through the reaction of a wide range of NHC‐derived selenoureas with commercially available diazo compounds, in the presence of triphenylphosphine. This transformation offers a new approach to such products, having biological, materials chemistry, and organic synthesis applications. The guanidine‐bearing azines are obtained in excellent yields, with all manipulations taking place in air. A reaction mechanism is proposed, based on both experimental mechanistic findings and density functional theory (DFT) calculations. A one‐pot, multicomponent transesterification reaction between selenoureas, α‐diazoesters, alcohols, and triphenylphosphine was also developed, providing highly functionalized azines. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Single Cu Atom Doping on Au11 Nanocluster: Its Implication toward Selectivity in C–C Coupling Reaction

Author

Mukherjee, Sayani, primary, Das, Amitabha, additional, Das, Anish Kumar, additional, Sheriff, Azmi, additional, Sunny, Kesiya, additional, Nair, Akhil S., additional, Bhandary, Subhrajyoti, additional, Bhowal, Rohit, additional, Chopra, Deepak, additional, Pathak, Biswarup, additional, Yamazoe, Seiji, additional, and Mandal, Sukhendu, additional

Published
2023
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16. Synthesis of Carbene‐Metal‐Amido (CMA) Complexes and Their Use as Precatalysts for the Activator‐Free, Gold‐Catalyzed Addition of Carboxylic Acids to Alkynes

Author

Ibni Hashim, Ishfaq, primary, Tzouras, Nikolaos V., additional, Janssens, Wim, additional, Scattolin, Thomas, additional, Bourda, Laurens, additional, Bhandary, Subhrajyoti, additional, Van Hecke, Kristof, additional, Nolan, Steven P., additional, and Cazin, Catherine S. J., additional

Published
2022
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22. A Green Synthesis of Carbene‐Metal‐Amides (CMAs) and Carboline‐Derived CMAs with Potentin vitroandex vivoAnticancer Activity

Author

Tzouras, Nikolaos V., primary, Scattolin, Thomas, additional, Gobbo, Alberto, additional, Bhandary, Subhrajyoti, additional, Rizzolio, Flavio, additional, Cavarzerani, Enrico, additional, Canzonieri, Vincenzo, additional, Van Hecke, Kristof, additional, Vougioukalakis, Georgios C., additional, Cazin, Catherine S. J., additional, and Nolan, Steven P., additional

Published
2022
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26. Single Cu Atom Doping on Au11Nanocluster: Its Implication toward Selectivity in C–C Coupling Reaction

Author

Mukherjee, Sayani, Das, Amitabha, Das, Anish Kumar, Sheriff, Azmi, Sunny, Kesiya, Nair, Akhil S., Bhandary, Subhrajyoti, Bhowal, Rohit, Chopra, Deepak, Pathak, Biswarup, Yamazoe, Seiji, and Mandal, Sukhendu

Abstract

Atom precise metal nanoclusters with customized surface structures are important for understanding the mechanism of surface engineering for appropriate applications. We are reporting a single copper doping on a very widely studied Au11(PPh3)7Cl3nanocluster, in which one chloride ligand is replaced by one Cu atom. Accordingly, a new bimetal nanocluster Cu1Au11(PPh3)7Cl2is produced, which consisted of a unique Au–Cu surface motif where the Cu is only bonded with an Au atom. In such a motif, the unsaturated Cu atom acts as an active catalyst for the Sonogashira reaction in contrast to the catalytically inactive Au11nanocluster. Moreover, it demonstrated a reversed selectivity in the Sonogashira cross-coupling reaction, where the major product obtained was homocoupled Glaser products in contrast to the selectivity of previously reported cluster/bimetallic clusters toward Ullmann or Sonogashira products. Theoretical calculations support the unsaturated Cu to be the active site on the nanocluster (NC) and act like a single-atom catalyst. This highlights the effect of mono copper atom doping on the unique selectivity in the Sonogashira cross-coupling reaction.

Published
2023
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28. Hydrogen bonding-enabled gold catalysis: ligand effects in gold-catalyzed cycloisomerizations in hexafluoroisopropanol (HFIP).

Author

Tzouras, Nikolaos V., Gobbo, Alberto, Pozsoni, Nestor Bracho, Chalkidis, Savvas G., Bhandary, Subhrajyoti, Van Hecke, Kristof, Vougioukalakis, Georgios C., and Nolan, Steven P.

Subjects
CYCLOISOMERIZATION, CATALYSIS, GOLD, HYDROGEN, SOLVENTS
Abstract

Gold catalysis has witnessed immense evolution in recent years, yet it still requires the use of activators to render the common [AuCl(L)] complexes catalytically active. Herein, the H-bonding donor properties of hexafluoroisopropanol (HFIP) are utilized for Au–Cl bond activation and the ancillary ligand and counteranion effects on cycloisomerization reactions are showcased in HFIP as solvent. [ABSTRACT FROM AUTHOR]

Published
2022
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31. Effect of chemical substitution on the construction of boroxine-based supramolecular crystalline polymers featuring B←N dative bonds.

Author

Bhandary, Subhrajyoti, Shukla, Rahul, and Van Hecke, Kristof

Subjects
*COORDINATE covalent bond, *CRYSTALLINE polymers, *SUPRAMOLECULAR polymers, *MOLECULAR structure, *POLYMER liquid crystals
Abstract

We report the mechanochemical synthesis of five single-crystalline phenylboroxine and 1,4-diazabicyclo[2.2.2]octane (DABCO) ligand-based adducts, directed by boron–nitrogen dative bonds. By tuning the electronic features of the phenylboroxines by chemical modifications (–H/–OMe/–F/–Cl/–Br) at the para-position, the formation of the resulting bicomponent adducts can be controlled to obtain molecular to 1D polymeric crystalline materials. The electrostatic and quantum topological aspects of the B←N bonds reveal the origin for the different binding modes of the boroxine–DABCO adducts yielding molecular to polymeric structures. [ABSTRACT FROM AUTHOR]

Published
2022
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32. Crystal Structure-Mechanical Property Correlations in N-(3-Ethynylphenyl)-3-fluorobenzamide Polymorphs

Author

Bhandary, Subhrajyoti, Mangalampalli, Kiran S. R. N., Ramamurty, Upadrasta, and Chopra, Deepak

Abstract

During the solution-mediated crystallization of N-(3-ethynylphenyl)-3-fluorobenzamide, small variation in the process conditions can lead to two new polymorphic forms in addition to the three previously reported forms. Structural features of the two new forms and mechanical properties of the three stable polymorphs, among the five forms, have been investigated using instrumented nanoindentation. The results show that among the three stable forms (Form I, Form II, and Form III) of the compound, the Form IIcrystal exhibits the lowest hardness (H) and elastic modulus (E), while these values are nearly similar for Form Iand Form IIIcrystals. Interestingly, the direct correlation of mechanical properties with the density of crystals was found for three polymorphs, but their melting points do not follow similar trends. The quantitative analysis of structural features with the inputs from energy frameworks suggests that the anisotropy in mechanical properties of the three polymorphs originate from the different orientations of strong to moderate N–H···O hydrogen bonds and weak to strong π···π stacking interactions, which mainly stabilize the crystal packing of the three polymorphs.

Published
2024
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33. Observation of Rapid Desolvation of Hexafluorobenzene Involving Single-Crystal-to-Single-Crystal Phase Transition in a Nonporous Organic Host

Author

Bhandary, Subhrajyoti and Chopra, Deepak

Abstract

We report an unusual occurrence of an extremely fast single-crystal-to-single-crystal phase transition induced by rapid desolvation of hexafluorobenzene at room temperature mediated by a subtle interplay of π···π stacking interactions in N-(3-ethynylphenyl)-4-fluorobenzamide. The nature of the host–guest stacking interaction has been explored in terms of interaction energy, electrostatic complementarity, and topological analysis with the inputs from reduced density gradient-noncovalent interactions fingerprint descriptor. Furthermore, the compound also exists in two other nonsolvated polymorphic forms.

Published
2024
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34. A Green Synthesis of Carbene‐Metal‐Amides (CMAs) and Carboline‐Derived CMAs with Potent in vitro and ex vivo Anticancer Activity

Author

Nikolaos V. Tzouras, Thomas Scattolin, Alberto Gobbo, Subhrajyoti Bhandary, Flavio Rizzolio, Enrico Cavarzerani, Vincenzo Canzonieri, Kristof Van Hecke, Georgios C. Vougioukalakis, Catherine S. J. Cazin, Steven P. Nolan, Tzouras, Nikolaos V, Scattolin, Thoma, Gobbo, Alberto, Bhandary, Subhrajyoti, Rizzolio, Flavio, Cavarzerani, Enrico, Canzonieri, Vincenzo, Van Hecke, Kristof, Vougioukalakis, Georgios C, Cazin, Catherine S J, and Nolan, Steven P

Subjects
Amide, Cytotoxicity, Carbene-metal-amides, Coinage metal-N-heterocyclic carbene complexes, Green chemistry, Synthetic methods, Amides, Carbolines, Humans, Ligands, Metals, Methane, Molecular Structure, Heterocyclic Compounds, Neoplasms, Settore BIO/11 - Biologia Molecolare, Ligand, Biochemistry, Carbene-metal-amide, Drug Discovery, Coinage metal-N-heterocyclic carbene complexe, General Pharmacology, Toxicology and Pharmaceutics, Pharmacology, Synthetic method, Metal, Organic Chemistry, Heterocyclic Compound, Carboline, Molecular Medicine, Human
Abstract

The modularity and ease of synthesis of carbene-metal-amide (CMA) complexes based on the coinage metals (Au, Ag, Cu) and N-heterocyclic carbenes (NHCs) as ancillary ligands pave the way for the expansion of their applications beyond photochemistry and catalysis. Herein, we further improve the synthesis of such compounds by circumventing the use of toxic organic solvents which were previously required for their purification, and we expand their scope to include complexes incorporating carbolines as the amido fragments. The novel complexes are screened both in vitro and ex vivo, against several cancer cell lines and high-grade serous ovarian cancer (HGSOC) tumoroids, respectively. Excellent cytotoxicity values are obtained for most complexes, while the structural variety of the CMA library screened thus far, provides promising leads for future developments. Variations of all three components (NHC, metal, amido ligand), enable the establishment of trends regarding cytotoxicity and selectivity towards cancerous over normal cells.

Published
2022
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35. The New Ag-S Cluster [Ag 50 S 13 (S t Bu) 20 ][CF 3 COO] 4 with a Unique hcp Ag 14 Kernel and Ag 36 Keplerian-Shell-Based Structural Architecture and Its Photoresponsivity.

Author

Biswas S, Das AK, Reber AC, Biswas S, Bhandary S, Kamble VB, Khanna SN, and Mandal S

Abstract

In metal nanoclusters (NCs), the kernel geometry and the nature of the surface protecting ligands are very crucial for their structural stability and properties. The synthesis and structural elucidation of Ag NCs is challenging because the zerovalent oxidation state of Ag is very reactive and prone to oxidization. Here, we report the NC [Ag 50 S 13 (S t Bu) 20 ][CF 3 COO] 4 with a hexagonal close-packed ( hcp ) cagelike Ag 14 kernel. A truncated cubic shell and an octahedral shell encapsulate the hcp -layered kernel via an interstitial S 2- anionic shell to form an Ag 36 Keplerian outer shell of the NC. A theoretical study indicates the stability of this NC in its 4+ charge state and the charge distribution between the kernel and Keplerian shell. The unprecedented electronic structure facilitates its application toward sustainable photoresponse properties. The new insights into this novel Ag NC kernel and Keplerian shell structure may pave the way to understanding the unique structure and developing electronic structure-based applications.

Published
2022
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