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Santra B, Kumar V, Kalita P, Gupta V, Mandal D, Chandra A, Joshi M, Choudhury AR, Jana A, Chandrasekhar V. Molecular di- and tetra-nuclear zinc(II) phosphates with sterically hindered aryl phosphate mono esters ligands. Polyhedron 2019. [DOI: 10.1016/j.poly.2019.06.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Mandal D, Dolai R, Kumar R, Suhr S, Chrysochos N, Kalita P, Narayanan RS, Rajaraman G, Schulzke C, Sarkar B, Chandrasekhar V, Jana A. Influence of N-Substitution on the Formation and Oxidation of NHC-CAAC-Derived Triazaalkenes. J Org Chem 2019; 84:8899-8909. [PMID: 31187990 DOI: 10.1021/acs.joc.9b00774] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We have studied the effect of N-substitution on the course of the reaction of imidazolium triflate. The reaction of N-heterocyclic carbene with N-tBu-substituted pyrrolinium triflate afforded 2-(pyrrolidin-2-yl)-imidazolium triflate, 3R. Treatment of 3R with potassium bis(trimethylsilyl)amide (KHMDS) leads to either the dealkylation product 4 or the deprotonation product, triazaalkene 5, depending on the N-substitution at the imidazolium moiety. Density functional studies using the B3LYP/TZVP setup have been employed to explore various pathways for the dealkylation reaction and the calculated energies support the dealkylation by a large energy margin compared to the deprotonatation process. Theoretical calculations revealed that dealkylation reaction is thermodynamically more favorable than deprotonation. The triazaalkene 5 could be oxidized by AgOTf to the corresponding radical cation 6 and dication 7 in-situ. While 6 and 7 could not be isolated, the formation of the former is inferred by electron paramagnetic resonance spectroscopy and its abstraction of a H-atom to afford 3Me. Similarly, the formation of the dication 7 is inferred by its ready elimination of isobutylene affording 8.
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Santra B, Narayanan RS, Kalita P, Kumar V, Mandal D, Gupta V, Zimmer M, Huch V, Chandrasekhar V, Scheschkewitz D, Schulzke C, Jana A. Modulation of the nuclearity of molecular Mg(ii)-phosphates: solid-state structural change involving coordinating solvents. Dalton Trans 2019; 48:8853-8860. [PMID: 31139786 DOI: 10.1039/c9dt00687g] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Herein, we report the synthesis and molecular structures of various magnesium(ii)-phosphate monoesters. By using a bulky aryl substituted phosphate monoester, ArOPO3H2 (Ar = 2,6-(CHPh2)2-4-tBu-C6H2), we have reproducibly assembled mono-, di-, tetra- (cage and ring), hexa-, and polynuclear magnesium(ii)-phosphate monoesters. Interestingly, the hexanuclear magnesium(ii)-phosphate monoester encapsulates an open-cage dodecanuclear water cluster.
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Biswas S, Kumar P, Swain A, Gupta T, Kalita P, Kundu S, Rajaraman G, Chandrasekhar V. Phosphonate-assisted tetranuclear lanthanide assemblies: observation of the toroidic ground state in the Tb III analogue. Dalton Trans 2019; 48:6421-6434. [PMID: 30993275 DOI: 10.1039/c9dt00592g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The reaction of LnCl3·6H2O with a multidentate flexible Schiff base ligand (LH4), H2O3PtBu and trifluoroacetic acid (tfaH) afforded a series of homometallic tetranuclear complexes, [Ln4(LH2)2(O3PtBu)2(μ2-η1η1tfa)2][2Cl] (Ln = DyIII (1), TbIII (2) and GdIII (3)). The tetranuclear lanthanide core contains two structurally different lanthanide centres, one being in a distorted trigonal dodecahedron geometry and the other in a distorted trigonal prism. Complexes 1-3 were investigated via direct and alternating current (DC and AC) magnetic susceptibility measurements. Only 1 revealed a weak single-molecule magnet (SMM) behaviour. Alternating current (ac) magnetic susceptibility measurements on 1 reveal a frequency-dependent out-of-phase signal. However, the absence of distinct maxima in the χ'' peak (within the temperature/frequency range of our experiments) prevented deduction of the experimental energy barrier for magnetization reversal (Ueff) and the relaxation time. We have carried out extensive ab initio (CASSCF + RASSI-SO + SINGLE_ANISO + POLY_ANISO) calculations on complexes 1-2 to gain deeper insights into the nature of magnetic anisotropy. Our calculations yielded only one exchange coupling parameter between the two LnIII centres bridged by the ligand (neglecting the exchange between the LnIII centres that are not proximal wrt each other). All the extracted J values indicate a weakly antiferromagnetic coupling between the metal centres (J = -0.025 cm-1 for 1 and J = -0.015 cm-1 for 2). Calculated exchange coupled Ucal values of ∼5 and ∼1 cm-1 in 1 and 2 respectively nicely corroborated the experimental observations regarding weak and no SMM characteristics. Our calculations indicated the presence of a net single-molecule toroidal (SMT) behaviour in complex 2. On the other hand, fitting the magnetic data (susceptibility and magnetization) in the isotropic cluster 3 revealed weak AFM exchange couplings of J1 = 0.025 cm-1 and J2 = -0.020 cm-1 which are consistent with those for GdIII ions.
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Kalita P, Malakar A, Goura J, Nayak S, Herrera JM, Colacio E, Chandrasekhar V. Mononuclear lanthanide complexes assembled from a tridentate NNO donor ligand: design of a Dy III single-ion magnet. Dalton Trans 2019; 48:4857-4866. [PMID: 30869724 DOI: 10.1039/c9dt00504h] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of a tridentate NNO donor ligand, 4-nitro-2-((2-(pyridine-2-yl)hydrazono)methyl)phenol (HL) with lanthanide(iii) nitrates in the presence of triethylamine afforded a new family of neutral mononuclear LnIII complexes [Ln(NO3)(L)2(HOCH3)] (Ln = Gd; (1) Tb; (2), Dy; (3), and Ho (4). The mononuclear complexes were structurally characterized by single crystal X-ray diffraction studies which revealed a spherical tricapped trigonal prism geometry with a pseudo D3h symmetry around the LnIII centre. Static (dc) and dynamic (ac) magnetic studies have been performed on these complexes. Field-induced single-ion magnet behaviour was observed in the DyIII analogue with an effective energy barrier and an pre-exponential factor of Δ/kB = 68(2) K and τ0 = 1.8 × 10-7 s, respectively.
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Mandal D, Sobottka S, Dolai R, Maiti A, Dhara D, Kalita P, Narayanan RS, Chandrasekhar V, Sarkar B, Jana A. Direct access to 2-aryl substituted pyrrolinium salts for carbon centre based radicals without pyrrolidine-2-ylidene alias cyclic(alkyl)(amino)carbene (CAAC) as a precursor. Chem Sci 2019; 10:4077-4081. [PMID: 31049189 PMCID: PMC6470959 DOI: 10.1039/c8sc05477k] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 02/27/2019] [Indexed: 12/20/2022] Open
Abstract
A new strategy to synthesise 2-substituted pyrrolinium salts.
The synthesis of organic radicals is challenging due to their inherent instability. In recent years, cyclic(alkyl)(amino)carbene (CAAC)-derived 2-substituted pyrrolinium salts have been used as synthons for the synthesis of isolable carbon-based radicals. Herein, we report a direct, easy and convenient method for the synthesis of 2-aryl substituted pyrrolinium salts without using CAAC as a precursor. These cations can be reduced to the corresponding radicals. The influence of the aryl substituent at the C-2 position on radical stabilization and dimerization has been investigated. Because of the large scope of our strategy (capability to modulate different substituents at all the C- and N-centres of the pyrrolinium salts), it has the merit to be an extremely effective and productive route for generating carbon-based radicals whose stability as well as reactivity can be varied.
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Santra B, Mandal D, Gupta V, Kalita P, Kumar V, Narayanan RS, Dey A, Chrysochos N, Mohammad A, Singh A, Zimmer M, Dalapati R, Biswas S, Schulzke C, Chandrasekhar V, Scheschkewitz D, Jana A. Structural Diversity in Supramolecular Organization of Anionic Phosphate Monoesters: Role of Cations. ACS OMEGA 2019; 4:2118-2133. [PMID: 31459460 PMCID: PMC6648147 DOI: 10.1021/acsomega.8b03192] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/02/2019] [Indexed: 06/10/2023]
Abstract
Syntheses and structures of anionic arylphosphate monoesters [ArOP(O)2(OH)]- (Ar = 2,6-CHPh2-4-R-C6H2; R = Me/Et/iPr/tBu) with different counter cations are reported. The counter cations were varied systematically: imidazolium cation, 2-methyl imidazolium cation, N-methyl imidazolium cation, N,N'-alkyl substituted imidazolium cation, 1,4-diazabicyclo[2.2.2]octan-1-ium cation, 4,4'-bipyridinium dication, and magnesium(II) dication. The objective was to examine if the supramolecular structure of anionic arylphosphate monoesters could be modulated by varying the cation. It was found that an eight-membered P2O4H2-hydrogen-bonded dimeric motif involving intermolecular H-bonding between the [P(O)(OH)] unit of the anionic phosphate monoester along with the counter cation is formed with 2-methyl imidazolium cation, N-methyl imidazolium cation, N,N'-alkyl substituted imidazolium cation, 1,4-diazabicyclo[2.2.2]octan-1-ium cation, and magnesium(II) dication; both discrete and polymeric H-bonded structures are observed. In the case of imidazolium cations and 1,4-diazabicyclo[2.2.2]octan-1-ium cation, the formation of one-dimensional polymers (single lane/double lane) was observed. On the other hand, two types of phosphate motifs, intermolecular H-bonded dimer and an open-form, were observed in the case of 4,4'-bipyridinium dication.
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Kalita P, Goura J, Manuel Herrera Martínez J, Colacio E, Chandrasekhar V. Homodinuclear {LnIII
2
} (LnIII
= GdIII
, TbIII
, HoIII
, and DyIII
) Complexes: Field-Induced SMM Behavior of the DyIII
and TbIII
Analogues. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201801049] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Dhara D, Vijayakanth T, Nayak MK, Kalita P, Boomishankar R, Yildiz CB, Chandrasekhar V, Jana A. Contrasting reactivity of (boryl)(aryl)lithium-amide with electrophiles: N- vs. p-aryl-C-nucleophilic substitution. Dalton Trans 2018; 47:14411-14415. [PMID: 30256354 DOI: 10.1039/c8dt03201g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein we report two different reactivity modes of lithium(aryl)(boryl)amide, 4, when it is reacted with chlorosilanes such as SiCl4 and MeSiHCl2, and chlorophosphine, Ph2PCl. Thus, the reaction of lithium(aryl)(boryl)amide, 4, with MeSiHCl2 leads exclusively to an N-substitution product, 6. On the other hand, the reaction of 4 with SiCl4 and Ph2PCl proceeds completely differently affording exclusively p-aryl-C-substitution products, 5 and 7, respectively.
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Schollmeier M, Ao T, Field ES, Galloway BR, Kalita P, Kimmel MW, Morgan DV, Rambo PK, Schwarz J, Shores JE, Smith IC, Speas CS, Benage JF, Porter JL. Polycapillary x-ray lenses for single-shot, laser-driven powder diffraction. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10F102. [PMID: 30399823 DOI: 10.1063/1.5036569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 06/03/2018] [Indexed: 06/08/2023]
Abstract
X-ray diffraction measurements to characterize phase transitions of dynamically compressed high-Z matter at Mbar pressures require both sufficient photon energy and fluence to create data with high fidelity in a single shot. Large-scale laser systems can be used to generate x-ray sources above 10 keV utilizing line radiation of mid-Z elements. However, the laser-to-x-ray energy conversion efficiency at these energies is low, and thermal x-rays or hot electrons result in unwanted background. We employ polycapillary x-ray lenses in powder x-ray diffraction measurements using solid target x-ray emission from either the Z-Beamlet long-pulse or the Z-Petawatt (ZPW) short-pulse laser systems at Sandia National Laboratories. Polycapillary lenses allow for a 100-fold fluence increase compared to a conventional pinhole aperture while simultaneously reducing the background significantly. This enables diffraction measurements up to 16 keV at the few-photon signal level as well as diffraction experiments with ZPW at full intensity.
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Hazarika A, Sarmah A, Borah R, Boro M, Dutta L, Kalita P, Choudhury BK. Discriminant feature level fusion based learning for automatic staging of EEG signals. Healthc Technol Lett 2018. [DOI: 10.1049/htl.2018.5024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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Dey A, Kalita P, Chandrasekhar V. Lanthanide(III)-Based Single-Ion Magnets. ACS OMEGA 2018; 3:9462-9475. [PMID: 31459081 PMCID: PMC6644820 DOI: 10.1021/acsomega.8b01204] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/03/2018] [Indexed: 05/27/2023]
Abstract
Mononuclear lanthanide-based single-ion magnets (SIMs) are known since 2003 with the discovery of SIM properties in a bis-(phthalocyaninato)lanthanide complex. A recent report on [Dy(Cpttt)2][BC6F5] indicating that it exhibits the highest known blocking temperature (60 K) has spurred fresh interest in this area. In this article, we discuss about the various requirements of lanthanide-based SIMs along with representative examples. Specifically, we describe the complexes whose coordination numbers vary from 2 to 8. We also discuss the representative examples of organometallic lanthanide complexes that can function as molecular magnets.
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Mandal D, Dolai R, Kalita P, Narayanan RS, Kumar R, Sobottka S, Sarkar B, Rajaraman G, Chandrasekhar V, Jana A. "Abnormal" Addition of NHC to a Conjugate Acid of CAAC: Formation of N-Alkyl-Substituted CAAC. Chemistry 2018; 24:12722-12727. [PMID: 29797625 DOI: 10.1002/chem.201802587] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Indexed: 01/16/2023]
Abstract
The addition reactions of N-heterocyclic carbenes (NHCs) are mostly known to occur through the carbenic centre (C2), which leads to a "normal" adduct. Herein, we report the "abnormal" addition of NHCDip 1 (1,3-(2,6-iPr2 C6 H3 )-imidazole-2-ylidene) to a conjugate acid of cyclic (alkyl)(amino)carbene 2 (CAACiPr =1-iPr-3,3,5,5-Me4 -pyrrolinium triflate). Mechanistic study revealed that this reaction proceeded through the in situ formation of 1,3-(2,6-iPr2 C6 H3 )-imidazolium cation 4 and N-iPr-substituted CAAC 5 followed by the oxidative addition of compound 5 across the C4-H bond (alias backbone C-H) of compound 4. The in situ formation of compound 5 was also proven by the oxidative addition of it to the N-H group of iPrNH2 . DFT calculations also supported the mechanistic findings. A different methodology for the in situ generation of compound 5 by using TMPLi is also described.
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Bar AK, Kalita P, Singh MK, Rajaraman G, Chandrasekhar V. Low-coordinate mononuclear lanthanide complexes as molecular nanomagnets. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2018.03.022] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Kalita P, Goura J, Herrera JM, Colacio E, Chandrasekhar V. Heterometallic Octanuclear Ni II 4Ln III 4 (Ln = Y, Gd, Tb, Dy, Ho, Er) Complexes Containing Ni II 2Ln III 2O 4 Distorted Cubane Motifs: Synthesis, Structure, and Magnetic Properties. ACS OMEGA 2018; 3:5202-5211. [PMID: 31458734 PMCID: PMC6641754 DOI: 10.1021/acsomega.8b00292] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 04/30/2018] [Indexed: 06/10/2023]
Abstract
The reaction of 2-methoxy-6-[{2-(2-hydroxyethylamino)ethylimino}methyl] phenol (LH3) with lanthanide metal salts followed by the addition of nickel acetate allowed isolation of a family of octanuclear complexes, [Ni4Ln4(μ2-OH)2(μ3-OH)4(μ-OOCCH3)8(LH2)4]·(OH)2·xH2O. Single crystal X-ray diffraction studies of these complexes reveal that their central metallic core consists of two tetranuclear [Ni2Ln2O4] cubane subunits fused together by acetate and hydroxide bridges. The magnetic study of these complexes reveals a ferromagnetic interaction between the LnIII and the NiII center. The magnitude of exchange coupling between the NiII and LnIII center, parametrized from the magnetic data of the Gd analogue, gives J = +0.86 cm-1. The magneto caloric effect, studied for the NiII 4GdIII 4 complex, shows a maximum of magnetic entropy change, -ΔS m = 22.58 J kg-1 K-1 at 3 K for an applied external field of 5 T.
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Dhara D, Kalita P, Mondal S, Narayanan RS, Mote KR, Huch V, Zimmer M, Yildiz CB, Scheschkewitz D, Chandrasekhar V, Jana A. Reactivity enhancement of a diphosphene by reversible N-heterocyclic carbene coordination. Chem Sci 2018; 9:4235-4243. [PMID: 29780553 PMCID: PMC5944230 DOI: 10.1039/c8sc00348c] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/26/2018] [Indexed: 01/05/2023] Open
Abstract
The reversible coordination of an N-heterocyclic carbene (NHC) enhances the reactivity of a diphosphene towards hydrolysis and transfer hydrogenation. The hydrolysis is catalytic in NHC.
Diphosphene TerMesP = PTerMes (1; TerMes = 2,6-Mes2C6H3; Mes = 2,4,6-Me3C6H2) and NHCMe42 (NHCMe4 = 1,3,4,5-tetramethylimidazol-2-ylidene) exist in an equilibrium mixture with the NHCMe4-coordinated diphosphene 3. While uncoordinated 1 is inert to hydrolysis, the NHC adduct 3 readily undergoes hydrolysis to afford a phosphino-substituted phosphine oxide with the liberation of NHCMe4. On this basis, conditions suitable for the catalytic use of NHCMe4 were identified. Similarly, while the hydrogenation of free diphosphene 1 with H3N·BH3 is very slow, 3 reacts instantaneously with H3N·BH3 at room temperature to afford a dihydrodiphosphane.
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Bar AK, Kalita P, Sutter JP, Chandrasekhar V. Pentagonal-Bipyramid Ln(III) Complexes Exhibiting Single-Ion-Magnet Behavior: A Rational Synthetic Approach for a Rigid Equatorial Plane. Inorg Chem 2018; 57:2398-2401. [DOI: 10.1021/acs.inorgchem.8b00059] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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43
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Dhara D, Mandal D, Maiti A, Yildiz CB, Kalita P, Chrysochos N, Schulzke C, Chandrasekhar V, Jana A. Assembly of NHC-stabilized 2-hydrophosphasilenes from Si(iv) precursors: a Lewis acid-base complex. Dalton Trans 2018; 45:19290-19298. [PMID: 27872933 DOI: 10.1039/c6dt04321f] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
NHC-stabilized 2-hydrophosphasilenes are obtained from 1,2-dihydro-2-chlorophosphasilanes as Si(iv) precursors by a NHC-assisted 1,2-elimination of HCl. The NHC-exchange of these compounds is demonstrated as a proof of donor acceptor bonding between NHC and the silicon centre of the "Si[double bond, length as m-dash]P" moiety. We have also explored the possibility of similar exchanges in NHC-stabilized Si2 and P2 compounds. Theoretical DFT calculations were performed to address the nature of Si-P bonding in the NHC-stabilized 2-hydrophosphasilenes.
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Gupta V, Santra B, Mandal D, Das S, Narayanan RS, Kalita P, Rao DK, Schulzke C, Pati SK, Chandrasekhar V, Jana A. Neutral and anionic phosphate-diesters as molecular templates for the encapsulation of a water dimer. Chem Commun (Camb) 2018; 54:11913-11916. [DOI: 10.1039/c8cc07138a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Neutral and anionic phosphate diesters act as molecular templates for the encapsulation of water dimers.
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Chakraborty A, Goura J, Kalita P, Swain A, Rajaraman G, Chandrasekhar V. Heterometallic 3d–4f single molecule magnets containing diamagnetic metal ions. Dalton Trans 2018; 47:8841-8864. [DOI: 10.1039/c8dt01883a] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This perspective deals with the synthesis and study of SMM properties of heterometallic 3d–4f complexes containing diamagnetic 3d metal ions.
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Mandal D, Santra B, Kalita P, Chrysochos N, Malakar A, Narayanan RS, Biswas S, Schulzke C, Chandrasekhar V, Jana A. 2,6-(Diphenylmethyl)-Aryl-Substituted Neutral and Anionic Phosphates: Approaches to H-Bonded Dimeric Molecular Structures. ChemistrySelect 2017. [DOI: 10.1002/slct.201701133] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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47
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Mandal D, Dolai R, Chrysochos N, Kalita P, Kumar R, Dhara D, Maiti A, Narayanan RS, Rajaraman G, Schulzke C, Chandrasekhar V, Jana A. Stepwise Reversible Oxidation of N-Peralkyl-Substituted NHC–CAAC Derived Triazaalkenes: Isolation of Radical Cations and Dications. Org Lett 2017; 19:5605-5608. [DOI: 10.1021/acs.orglett.7b02721] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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48
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Biswas S, Bejoymohandas KS, Das S, Kalita P, Reddy MLP, Oyarzabal I, Colacio E, Chandrasekhar V. Mononuclear Lanthanide Complexes: Energy-Barrier Enhancement by Ligand Substitution in Field-Induced Dy III SIMs. Inorg Chem 2017; 56:7985-7997. [PMID: 28661123 DOI: 10.1021/acs.inorgchem.7b00689] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The sequential reaction of 2-((6-(hydroxymethyl)pyridin-2-yl)-methyleneamino)phenol (LH2), LnCl3·6H2O, and 1,1,1-trifluoroacetylacetone (Htfa) in the presence of Et3N afforded [Ln(LH) (tfa)2] [Ln = Dy3+ (1), Ln = Tb3+ (2), and Ln = Gd3+ (3)], while under the same reaction conditions, but in the absence of the coligand, another series of mononuclear complexes, namely, [Ln(LH)2]·Cl·2MeOH] [Ln = Dy3+ (4) and Tb3+ (5)] are obtained. Single-crystal X-ray diffraction analysis revealed that the former set contains a mono-deprotonated [LH]- and two tfa ligands, while the latter set comprises of two mono-deprotonated [LH]- ligands that are nearly perpendicular to each other at an angle of 86.9°. Among these complexes, 2 exhibited a ligand-sensitized lanthanide-characteristic emission. Analyses of the alternating current susceptibility measurements reveal the presence of single-molecule magnet behavior for 1 and 4, in the presence of direct-current field, with effective energy barriers of 4.6 and 44.4 K, respectively. The enhancement of the effective energy barrier of the latter can be attributed to the presence of a large energy gap between the ground and first excited Kramers doublets, triggered by the change in coordination environments around the lanthanide centers.
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Howe DG, Bradford YM, Eagle A, Fashena D, Frazer K, Kalita P, Mani P, Martin R, Moxon ST, Paddock H, Pich C, Ramachandran S, Ruzicka L, Schaper K, Shao X, Singer A, Toro S, Van Slyke C, Westerfield M. A scientist's guide for submitting data to ZFIN. Methods Cell Biol 2016; 135:451-81. [PMID: 27443940 DOI: 10.1016/bs.mcb.2016.04.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The Zebrafish Model Organism Database (ZFIN; zfin.org) serves as the central repository for genetic and genomic data produced using zebrafish (Danio rerio). Data in ZFIN are either manually curated from peer-reviewed publications or submitted directly to ZFIN from various data repositories. Data types currently supported include mutants, transgenic lines, DNA constructs, gene expression, phenotypes, antibodies, morpholinos, TALENs, CRISPRs, disease models, movies, and images. The rapidly changing methods of genomic science have increased the production of data that cannot readily be represented in standard journal publications. These large data sets require web-based presentation. As the central repository for zebrafish research data, it has become increasingly important for ZFIN to provide the zebrafish research community with support for their data sets and guidance on what is required to submit these data to ZFIN. Regardless of their volume, all data that are submitted for inclusion in ZFIN must include a minimum set of information that describes the data. The aim of this chapter is to identify data types that fit into the current ZFIN database and explain how to provide those data in the optimal format for integration. We identify the required and optional data elements, define jargon, and present tools and templates that can help with the acquisition and organization of data as they are being prepared for submission to ZFIN. This information will also appear in the ZFIN wiki, where it will be updated as our services evolve over time.
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Bandyopadhyay S, Mahajan M, Mehta T, Singh AK, Gupta AK, Parikh A, Kalita P, Patel M, Mendiratta SK. Physicochemical and functional characterization of a biosimilar adalimumab ZRC-3197. ACTA ACUST UNITED AC 2014. [DOI: 10.2147/bs.s75573] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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