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Sharma K, Gupta SK, Borah A, Murugavel R. Hitherto unknown eight-connected frameworks formed from A 4B 4O 12 metal organophosphate heterocubanes. Chem Commun (Camb) 2019; 55:7994-7997. [PMID: 31225572 DOI: 10.1039/c9cc01893j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Modulation of a functional group on the distal part of a phosphate ester has been prudently exploited to selectively switch between the formation of D4R SBUs and 3-D framework structures. While amino substitution at the para-position of an aryl phosphate results in the isolation of tetra-amino functionalized discrete D4R zinc phosphate or its 4-connected 3-D framework, the introduction of an acetylamino substituent leads to a single-step assembly of a rare eight-connected 3-D framework solid.
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Antony R, Marimuthu R, Murugavel R. Bimetallic Nanoparticles Anchored on Core-Shell Support as an Easily Recoverable and Reusable Catalytic System for Efficient Nitroarene Reduction. ACS OMEGA 2019; 4:9241-9250. [PMID: 31460014 PMCID: PMC6648521 DOI: 10.1021/acsomega.9b01023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 05/16/2019] [Indexed: 05/05/2023]
Abstract
We report an easily recoverable and reusable versatile magnetic catalyst (Fe3O4@CS_AgNi, where CS = chitosan) for organic reduction reactions. The catalytic system is prepared by dispersing AgNi bimetallic nanoparticles on the magnetite core-shell (Fe3O4@CS). The as-synthesized catalyst has been characterized by spectroscopic techniques, such as IR, UV-vis, and X-ray photoelectron spectroscopy (XPS), and analytical tools, such as thermogravimetric analysis, powder X-ray diffraction, Brunauer-Emmett-Teller adsorption, FEG-scanning electron microscopy, high-resolution transmission electron microscopy (HR-TEM), inductively coupled plasma-atomic emission spectroscopy, and magnetic measurements. HR-TEM studies indicate the core-shell structure of Fe3O4@CS and confirm the presence of AgNi nanoparticles on the surface of Fe3O4@CS spheres. IR spectral and XPS studies lend evidence for the occurrence of a strong chemical interaction between the amino groups of CS and AgNi nanoparticles. The nano-catalyst Fe3O4@CS_AgNi rapidly reduces p-nitrophenol to p-aminophenol using NaBH4 as the reductant within a few minutes under ambient conditions (as monitored by UV-visible spectroscopy). The utility of this catalytic system has also been extended to the reduction of other nitroarenes. A strong interaction between Fe3O4@CS and AgNi nanoparticles impedes the leaching of AgNi nanoparticles from the core-shell support, leading to excellent reusability of the catalyst.
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Bhat GA, Maqbool R, Dar AA, Ul Hussain M, Murugavel R. Selective formation of discrete versus polymeric copper organophosphates: DNA cleavage and cytotoxic activity. Dalton Trans 2018; 46:13409-13420. [PMID: 28948250 DOI: 10.1039/c7dt02763j] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Copper phosphate metalloligands [Cu(X-dipp)(Pyterpy)]2 [X = H (1), Br (2)], exemplifying expanded 4,4'-bipyridine type molecules, have been synthesized by reacting 4'-(4-pyridyl)-2,2':6',2''-terpyridine (Pyterpy) and para substituted 2,6-diisopropylphenyl phosphate (X-dippH2) with copper acetate. The pendant N,N-ends of dimeric copper phosphates 1 and 2 have been forced to engage in further coordination by limiting the concentration of Pyterpy in the reaction mixture to yield rare Pyterpy bridged corner-shared polymeric copper phosphates [Cu2(X-dippH)(X-dipp)(Pyterpy)(H2O)]n [X = Cl (3), Br (4), I (5)]. The formation of 1-5 is supported by spectroscopic and analytical data. The solid state structures of these compounds have further been confirmed by single-crystal X-ray diffraction studies. Soluble dimeric complexes 1 and 2 have been assessed for their in vitro anti-tumour properties against human breast and colorectal cancer cell lines. The DNA cleavage, protein cleaving and cytotoxicity assays revealed that these compounds are effective in cleaving DNA, while the activity of 1 as an anti-tumor agent is better than 2.
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Murugavel R, Rao CNR. A decade of "Chemical Frontiers Goa". RSC Adv 2018; 8:28602-28603. [PMID: 35542467 PMCID: PMC9084344 DOI: 10.1039/c8ra90068j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 08/02/2018] [Indexed: 11/21/2022] Open
Abstract
We are delighted to present this collection of open access articles in RSC Advances to celebrate the Decennial Year of the "Chemical Frontiers Goa" meetings.
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Jangir R, Kaleeswaran D, Murugavel R. 2,2′,6,6′-Tetraisopropylbenzidine-Based Sterically Encumbered DitopicC2-Symmetric Ligand Systems and Supramolecular Building Blocks. ChemistrySelect 2018. [DOI: 10.1002/slct.201801320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Bhat GA, Verma S, Rajendran A, Murugavel R. Thermolabile Organotitanium Monoalkyl Phosphates: Synthesis, Structures, and Utility as Epoxidation Catalysts and Single-Source Precursors for TiP 2O 7. Inorg Chem 2018; 57:7644-7654. [PMID: 29906112 DOI: 10.1021/acs.inorgchem.8b00611] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The reaction of [Cp*TiCl3] (Cp* = C5Me5) with monoalkyl phosphates (RO)PO3H2 (R = Me, Et, and iPr) in tetrahydrofuran (THF) at 25 °C leads to the formation of binuclear complexes [Cp*2Ti2(μ-O2P(OH)OR)2(μ-O2P(O)OR)2] [R = Me (1), Et (2), and iPr (3)]. On the other hand, the reaction of ( tBuO)2PO2K with [Cp*TiCl3] in acetonitrile or THF results in isolation of either the dinuclear [Cp*2Ti2(μ-O2P(OH)O tBu)2(μ-O2P(O)O tBu)2] (4) or the trinuclear titanophosphate [Cp*3Ti3(μ-O3PO tBu)2(μ-O)2(μ-O2P(O tBu)2)] (5), respectively. The formation of compounds 4 and 5 is facilitated by partial hydrolysis of the tert-butoxy groups of ( tBuO)2PO2K. New titanophosphates 1-5 have been characterized by spectroscopic and analytical methods, and the molecular structures have further been confirmed by single-crystal X-ray diffraction studies. Thermal decomposition studies of 1-5 reveal the initial loss of thermally labile alkyl substituents of the organophosphate ligands, followed by the loss of C5Me5 groups to form an organic-free amorphous titanophosphate in the temperature range 300-500 °C. This material transforms to highly crystalline titanium pyrophosphate TiP2O7 at 800 °C. Compounds 1-5 and the TiP2O7 materials obtained at 300, 500, and 800 °C through the thermal decomposition of 3 have been employed as efficient homogeneous catalysts for the alkene epoxidation reaction. Using hydrogen peroxide as the oxidant in an acetonitrile medium, these catalysts exhibit >90% alkene conversion with >90% epoxide selectivity in 4 h at temperatures below 100 °C.
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Bhat GA, Rajendran A, Murugavel R. Polydentate 4-Pyridyl-terpyridine Containing Discrete Cobalt Phosphonate and Polymeric Cobalt Phosphate as Catalysts for Alcohol Oxidation. Z Anorg Allg Chem 2018. [DOI: 10.1002/zaac.201800091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Gupta SK, Murugavel R. Enriching lanthanide single-ion magnetism through symmetry and axiality. Chem Commun (Camb) 2018; 54:3685-3696. [PMID: 29564454 DOI: 10.1039/c7cc09956h] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Rapidly growing modern information technology demands energy and cost efficient tools that can efficiently store and process a large amount of data. However, the miniaturization technology that was being used to boost the performance of the electronic devices, keeping up with the pace as estimated by Moore's law, is reaching its limit. To overcome these challenges, several alternative routes that can eventually mimic the modern electronics fabrication using silicon have been proposed. Single molecule magnets (SMMs), being considered as one of the potential alternatives, have gone through significant progress and the focus has shifted from the use of polynuclear clusters to mononuclear complexes in the last few years. The recent frenzy in the field of SMMs is driven by a better understanding of the effects of crystal field (CF) and molecular symmetry on the magnetic properties, especially in the case of mononuclear paramagnetic complexes, apart from other controlling factors. This has led to the advent of highly anisotropic single-ion magnets (SIMs) with magnetic blocking temperatures as high as 60 K and anisotropic energy barriers over 1800 K. This article overviews our recent research in the light of the emergence of the importance of CF and symmetry in 4f ion based single-ion magnets (SIMs), especially in the context of SIMs with D5h symmetry, apart from commenting on the synthetic efforts adopted to place these metal ions in unusual coordination geometries.
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Jangir R, Kalita AC, Kaleeswaran D, Gupta SK, Murugavel R. A [4+2] Condensation Strategy to Imine-Linked Single-Crystalline Zeolite-Like Zinc Phosphate Frameworks. Chemistry 2018; 24:6178-6190. [DOI: 10.1002/chem.201800149] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Indexed: 01/02/2023]
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Bhat GA, Rajendran A, Murugavel R. Dinuclear Manganese(II), Cobalt(II), and Nickel(II) Aryl Phosphates Incorporating 4′-Chloro-2,2′:6′,2′′-Terpyridine Coligands - Efficient Catalysts for Alcohol Oxidation. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201701064] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Gupta SK, Rajeshkumar T, Rajaraman G, Murugavel R. Is a strong axial crystal-field the only essential condition for a large magnetic anisotropy barrier? The case of non-Kramers Ho(iii) versus Tb(iii ). Dalton Trans 2018; 47:357-366. [PMID: 29215670 DOI: 10.1039/c7dt04020b] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A monometallic non-Kramers Ho(iii) complex with a strong uniaxial ligand field displays a record high energy barrier of 355 K with hysteresis opening up to 4 K at a sweep rate of 0.027 T s-1, while the isomorphous, more anisotropic non-Kramers Tb(iii) complex displays strong quantum tunnelling between the ground states. Ab initio calculations reveal that the presence of strong axial ligands and moderately weaker equatorial ligands is sufficient to quench the QTM between the ground pseudo doublets (mJ = ±8) in the case of Ho(iii) complex, where the relaxation is found to proceed via the first excited state. However, the equatorial field disrupts the stabilization of ground pseudo doublets in Tb(iii), inducing QTM and inhibiting SIM behaviour. Further insights into the decisive role played by the secondary coordination sphere and hydrogen-bonding in the SIM characteristics of these two non-Kramers ions were also gained. This combined experimental and computational approach highlights that although strong axiality holds the key for designing high temperature SIMs based on oblate non-Kramers ions, the strength of the equatorial ligand field also cannot be ignored.
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Vishnoi P, Kaleeswaran D, Murugavel R. 1,3,5-Triphenylbenzene: a versatile photoluminescent chemo-sensor platform and supramolecular building block. RSC Adv 2018; 8:17535-17550. [PMID: 35539277 PMCID: PMC9081830 DOI: 10.1039/c8ra02658k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 04/26/2018] [Indexed: 12/15/2022] Open
Abstract
Rich and diverse chemistry of 1,3,5-triphenylbenzene is discussed with emphasis on fluorescence based chemo-sensors, apart from a discussion on its use in building a number of supramolecular assemblies and fluorescent covalent-organic-frameworks.
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Antony R, Marimuthu R, Vishnoi P, Murugavel R. Ethoxysilane appended M(II) complexes and their SiO2/MCM-41 supported forms as catalysts for efficient oxidation of secondary alcohols. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.09.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Vishnoi P, Kaleeswaran D, Murugavel R. Rare Supramolecular Assemblies of a Dicopper(II)-tetracarboxylate Stabilized by (Methanol)6
, Dimethyl Sulfoxide and 4,4′-Azobipyridyl Bridges. ChemistrySelect 2017. [DOI: 10.1002/slct.201702862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Wu Y, Shaker S, Brivio F, Murugavel R, Bristowe PD, Cheetham AK. [Am]Mn(H 2POO) 3: A New Family of Hybrid Perovskites Based on the Hypophosphite Ligand. J Am Chem Soc 2017; 139:16999-17002. [PMID: 29069898 DOI: 10.1021/jacs.7b09417] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A family of five hybrid ABX3 perovskites has been synthesized using hypophosphite (H2POO)- as the X-site ion. These compounds adopt the general formula [Am]Mn(H2POO)3, where Am = guanidinium (GUA), formamidinium (FA), imidazolium, triazolium, and dabconium. We explore the diverse structural and phase transition behavior of these materials through single-crystal diffraction measurements and demonstrate contrasting magnetism in two of the phases, Am = GUA and FA, that arises from structural distortions. The results show that hypophosphite perovskites offer a promising platform for generating new functional materials.
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Sharma K, Antony R, Kalita AC, Gupta SK, Davis P, Murugavel R. Complex Structural Landscape of Titanium Organophosphonates: Isolation of Structurally Related Ti4, Ti5, and Ti6 Species and Mechanistic Insights. Inorg Chem 2017; 56:12848-12858. [DOI: 10.1021/acs.inorgchem.7b01651] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Saxena P, Murugavel R. Bulky 2,6-Dibenzhydryl-4-methylaniline Derived Schiff Base Complexes of Pd(II) as Efficient Catalysts for Suzuki Coupling: Effect of Coordinated Anion on the Catalytic Activity. ChemistrySelect 2017. [DOI: 10.1002/slct.201702035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kaleeswaran D, Antony R, Sharma A, Malani A, Murugavel R. Catalysis and CO2Capture by Palladium-Incorporated Covalent Organic Frameworks. Chempluschem 2017; 82:1253-1265. [DOI: 10.1002/cplu.201700342] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 09/11/2017] [Indexed: 02/01/2023]
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Gupta S, Kaleeswaran D, Nandi S, Vaidhyanathan R, Murugavel R. Bulky Isopropyl Group Loaded Tetraaryl Pyrene Based Azo-Linked Covalent Organic Polymer for Nitroaromatics Sensing and CO 2 Adsorption. ACS OMEGA 2017; 2:3572-3582. [PMID: 31457676 PMCID: PMC6641411 DOI: 10.1021/acsomega.7b00515] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 06/30/2017] [Indexed: 05/03/2023]
Abstract
An azo-linked covalent organic polymer, Py-azo-COP, was synthesized by employing a highly blue-fluorescent pyrene derivative that is multiply substituted with bulky isopropyl groups. Py-azo-COP was investigated for its sensing and gas adsorption properties. Py-azo-COP shows selective sensing toward the electron-deficient polynitroaromatic compound picric acid among the many other competing analogs that were investigated. Apart from its chemosensing ability, Py-azo-COP (surface area 700 m2 g-1) exhibits moderate selectivity toward adsorption of CO2 and stores up to 8.5 wt % of CO2 at 1 bar and 18.2 wt % at 15.5 bar at 273 K, although this is limited due to the electron-rich -N=N- linkages being flanked by isopropyl groups. Furthermore, the presence of a large number of isopropyl groups imparts hydrophobicity to Py-azo-COP, as confirmed by the increased adsorption of toluene compared to that of water in the pores of the COP.
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Gupta SK, Bhat GA, Murugavel R. Lanthanide Organophosphate Spiro Polymers: Synthesis, Structure, and Magnetocaloric Effect in the Gadolinium Polymer. Inorg Chem 2017; 56:9071-9083. [DOI: 10.1021/acs.inorgchem.7b01100] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Saxena P, Murugavel R. Bulky 2,6-Dibenzhydryl-4-methylaniline Derived Schiff Base Complexes of Pd(II), Cu(II) and Co(II) as Efficient Catalysts for Suzuki Coupling and Alcohol Oxidation Reactions. ChemistrySelect 2017. [DOI: 10.1002/slct.201700657] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Gupta SK, Langley SK, Sharma K, Murray KS, Murugavel R. Pentanuclear Lanthanide Mono-organophosphates: Synthesis, Structure, and Magnetism. Inorg Chem 2017; 56:3946-3960. [DOI: 10.1021/acs.inorgchem.6b03014] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Nagendran S, Vishnoi P, Murugavel R. Triphenylbenzene Sensor for Selective Detection of Picric Acid. J Fluoresc 2017; 27:1299-1305. [PMID: 28293816 DOI: 10.1007/s10895-017-2063-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 03/02/2017] [Indexed: 11/26/2022]
Abstract
A C 3-symmetric triphenylbenzene based photoluminescent compound, 1,3,5-tris(4'-(N-methylamino)phenyl) benzene ([NHMe]3TAPB), has been synthesized by mono-N-methylation of 1,3,5-tris(4'-aminophenyl) benzene (TAPB) and structurally characterized. [NHMe]3TAPB acts as a selective fluorescent sensor for picric acid (PA) with a detection limit as low as 2.25 ppm at a signal to noise ratio of 3. Other related analytes (i.e. TNT, DNT and DNB) show very little effect on the fluorescence intensity of [NHMe]3TAPB. The selectivity is triggered by proton transfer from picric acid to the fluorophore and ground-state complex formation between the protonated fluorophore and picrate anion through hydrogen bonding interactions. The fluorescence lifetime measurements reveal static nature of fluorescence quenching.
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Bhat GA, Kalita AC, Murugavel R. Intriguing structural chemistry of neutral and anionic layered monoalkylphosphates: single-source precursors for high-yield ceramic phosphates. CrystEngComm 2017. [DOI: 10.1039/c7ce01066d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A simple protocol for multi-gram synthesis of unstable and normally inaccessible phosphate monoesters ROPO3H2 is reported, apart from demonstration of their thermal instability and utility as starting materials for metal phosphate single source precursors.
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Sharma K, Kalita AC, Murugavel R. Five different pseudo-polymorphs of 4-aminoarylphosphate: supramolecular aggregation in organophosphates. CrystEngComm 2017. [DOI: 10.1039/c6ce02215d] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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