- Coordinatively Unsaturated Lanthanide(III) Helicates: Luminescence Sensors for Adenosine Monophosphate in Aqueous Media
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Coordinatively unsaturated double-stranded helicates [(H2L)2Eu2(NO3)2(H2O)4](NO3)4, [(H2L)2Tb2(H2O)6](NO3)6, and [(H2L)2Tb2(H2O)6]Cl6(H2L=butanedioicacid-1,4-bis[2-(2-pyridinylmethylene)hydrazide]) are easily obtained by self-assembly from the ligand and the corresponding lanthanide(III) salts. The complexes are characterized by X-ray crystallography showing the helical arrangement of the ligands. Co-ligands at the metal ions can be easily substituted by appropriate anions. A specific luminescence response of AMP in presence of ADP, ATP, and other anions is observed. Specificity is assigned to the perfect size match of AMP to bridge the two metal centers and to replace quenching co-ligands in the coordination sphere.
- Sahoo, Jashobanta,Arunachalam, Rajendran,Subramanian, Palani S.,Suresh, Eringathodi,Valkonen, Arto,Rissanen, Kari,Albrecht, Markus
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- Synthesis, spectroscopic and electrochemical characterisation of binuclear dioxomolybdenum complexes derived from disalicylaldehyde succinoyldihydrazone
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The diamagnetic dioxomolybdenum (VI) complexes [(MoO2) 2(L).(H2O)2] where H4L = H 4slsh have been isolated in solid state from the reaction of MoO 2(acac)2 and disalicylaldehyde succinoyldihydrazone (H4L) in 3:1 molar ratio in ethanol at higher temperature. The reaction of the complex with electron donor bases gives diamagnetic molybdenum(VI) complexes having composition [(MoO2) 2(L)(A)2]·H2O (where A = pyridine (py, 2), 2-picoline (2-pic, 3), 3-picoline (3-pic, 4), 4-picoline (4-pic, 5). The composition of the complexes have been established by analytical, thermo-analytical data. The structure of the molybdenum (VI) complexes has been established by mass, electronic, IR, 1H NMR and CV spectral studies. The dihydrazone is coordinated to the metal centres in staggered configuration in all the complexes. The electronic spectra of the complexes are dominated by strong charge transfer bands. All of the complexes involve six coordinated molybdenum centre with octahedral arrangement of donor atoms.
- Ahmed, Aziz,Chanu, Oinam B.,Koch, Angira,Lal
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- Molecular Recognition-Mediated Transformation of Single-Chain Polymer Nanoparticles into Crosslinked Polymer Films
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We describe single-chain polymer nanoparticles (SCNPs) possessing intramolecular dynamic covalent crosslinks that can transform into polymer films through a molecular recognition-mediated crosslinking process. The SCNPs utilise molecular recognition with surface-immobilised proteins to concentrate upon a substrate, bringing the SCNPs into close spatial proximity with one another and allowing their dynamic covalent crosslinkers to undergo intra- to interpolymer chain crosslinking leading to the formation of polymeric film. SCNPs must possess both the capacity for specific molecular recognition and a dynamic nature to their intramolecular crosslinkers to form polymer films, and an investigation of the initial phase of film formation indicates it proceeds from features which form upon the surface then grow predominantly in the xy directions. This approach to polymer film formation presents a potential method to “wrap” surfaces displaying molecular recognition motifs—which could potentially include viral, cellular and bacterial surfaces or artificial surfaces displaying multivalent recognition motifs—within a layer of polymer film.
- Mahon, Clare S.,McGurk, Christopher J.,Watson, Scott M. D.,Fascione, Martin A.,Sakonsinsiri, Chadamas,Turnbull, W. Bruce,Fulton, David A.
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- Supramolecular interactions in a family of dinuclear helicates in the solid-state
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Metallo-helicates are a commonly encountered assembly within supramolecular chemistry. Interest in these architectures stems from their inherent helical chirality which positions them for a diverse range of applications such as catalysis and non-linear optics (NLO). The current study uses Co(II) dinuclear double helicates as versatile supramolecular synthons. The ditopic ligand, L, features two tridentate quinolinyl-hydrazone binding sites imparting it with hydrogen bond donors and π-faces for secondary supramolecular interactions. Incorporation of L into [Co2(L)2]4+ helical assemblies results in a helical cationic supramolecular synthon with moieties predisposed to forming π-π stacking and hydrogen bond interactions. The single-crystal X-ray structures of [Co2(L)2]X4 (X?=?ClO4?, BF4? and CF3SO3?) revealed a variety of anion dependent hydrogen bond networks arising through the interaction of the hydrazide hydrogen with the anion. These interactions in turn strongly influence the nature of the π-π stacking interactions of the quinoline moieties which can be analysed via the Hirshfield surface.
- Kruger, Paul E.,Wilson, Benjamin H.
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- Synthesis and characterization of heterobimetallic Ni(II)-Zn(II) complexes from bis(2-hydroxy-1 -naphthaldehyde)succinoyldihydrazone
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Monometallic zinc(II) and nickel(II) complexes, [Zn(H2nsh)(H2O)] (1) and [Ni(H2nsh)(H2O)2] (2), have been synthesized in methanol by template method from bis(2-hydroxy-1-naphthaldehyde)succinoyldihydrazone (H4nsh). Reaction of monometallic complexes with alternate metal(II) acetates as a transmetallator in 1: 3 molar ratio resulted in the formation of heterobimetallic complexes [NiZn(nsh)(A)3] and [ZnNi(nsh)(A′)2] (A′ = H2O (3), py (4), 2-pic (5), 3-pic (6), 4-pic (7)), (A' = H2O (8), py (9), 2-pic (10), 3-pic (11), and 4-pic (12)). The complexes have been characterized by elemental analyzes, mass spectra, molar conductance, magnetic moments, electronic, EPR, and IR spectroscopies. All of the complexes are non-electrolytes. Monometallic zinc(II) is diamagnetic while monometallic nickel(II) complex and all heterobimetallic complexes are paramagnetic. The metal centers in heterobimetallic complexes are tethered by dihydrazone and naphthoxo bridging. Zinc(II) is square pyramidal; nickel(II) is six-coordinate distorted octahedral except [ZnNi(nsh)(A)2], in which nickel(II) has square-pyramidal geometry. The displacement of metal center in monometallic complexes by metal ion has been observed in the resulting heterobimetallic complexes.
- Lal,Chakraborty,Chanu,Choudhury,Borthakur,Copperfield,Kumar
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- Synthesis and spectral characterization of homobimetallic molybdenum(VI) complexes derived from bis(2-hydroxy-1-naphthaldehyde)succinoyldihydrazone
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The reaction of bis(2-hydroxy-1-naphthaldehyde)succinoyldihydrazone with bis(acetylaceto-nato)dioxomolybdenum(VI) (MoO2(acac)2) in 1: 3 molar ratio in EtOH: water mixture (95: 5) affords a complex of composition [(MoO2)2(nsh)(H2O)2]·C2H5OH. The reaction of [(MoO2)2 (nsh)(H2O)2]·C2H5OH with Lewis bases, namely pyridine,2-picoline,3-picoline, and 4-picoline, yields[(MoO2)2(nsh)(B)2]·C2H5OH (where B=pyridine,2-picoline,3-picoline, and 4-picoline). Further, when this complex was reacted with 1,10-phenanthroline and 2,2′-bipyridine in 1:3 molar ratio in anhydrous ethanol the binuclear complexes [(μ2-O)2(MoO2)2 (H4nsh)(phen)]·C2H5OH and [(μ2-O)2(MoO2)2 (H4nsh)(bpy)]·C2H5OH were obtained. All of the complexes have been characterized by analytical, magnetic moment, and molar conductivity data. The structures of the complexes have been discussed in the light of electronic, IR, 1H NMR, and 13C NMR spectroscopy.
- Lal, Ram A.,Chakrabarty, Mithun,Choudhury, Sanjesh,Ahmed, Aziz,Borthakur, Roshmita,Kumar, Arvind
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- FLOW CHEMISTRY SYNTHESIS OF ISOCYANATES
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The disclosure provides, inter alia, safe and environmentally-friendly methods, such as flow chemistry, to synthesize isocyanates, such as methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetramethylxylene diisocyanate.
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Paragraph 0175; 0240; 0243
(2021/06/22)
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- The fabrication and characterization of a supramolecular Cu-based metallogel thin-film based Schottky diode
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In the present study, a stable supramolecular Cu(ii)-metallogel has been synthesized based on copper(ii) acetate monohydrate and succinic acid, engineered as a low-molecular-weight organic gelator. The mechanical assets of the Cu-H4L metallogel have been explored through a rheological investigation. Further, the aggregation of the synthesized metallogel has been well establishedviaseveral experiments using Job plots and ESI-MS. Apart from this, the morphology of the synthesized supramolecular metallogel was scrutinizedviaFESEM, TEM, and AFM studies, revealing the self-assembled thread-like morphology of the Cu-H4L metallogel. The functional group, elemental composition, crystalline behaviour, and thermal stability of the Cu-H4L metallogel were probedviaFT-IR, XPS, P-XRD, and TGA studies, respectively. The optical properties of the Cu-H4L metallogel reflected its semiconducting nature. Thus, based on the semiconducting properties of the Cu-H4L metallogel, we have successfully fabricated an active electronic device: a ‘Schottky diode’.
- Kumar, Vivek,Upadhyay, Rishibrind Kumar,Bano, Daraksha,Chandra, Subhash,Kumar, Deepak,Jit, Satyabrata,Hasan, Syed Hadi
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p. 6273 - 6280
(2021/04/16)
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- Synthesis, characterization, crystal structure, and reactivity of heterobimetallic dioxovanadium(V) complexes containing multidentate hydrazone ligands
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Two new heterobimetallic complexes of the composition [(VO2)2(μ3-slsch){Na2(μ-H2O)2(H2O)2}]n (1) and [(VO2)2(μ3-npsch){Na2(μ-H2O)2(H2O)2}(DMF)]n (2) were obtained by reaction of the ligand and vanadium pentoxide in a 1:1 molar ratio in methanol in the presence of Na2CO3 (2 equivalents). The complexes obtained were characterized using various spectroscopic studies. The structures of both the complexes were established by single crystal X-ray crystallographic study. We have also explored the catalytic behavior of the complexes in oxidative bromination of phenol red, which is the bio-inspired reaction catalyzed by an enzyme haloperoxidase.
- Kurbah, Sunshine D.,Kumar, Arvind,Sanentiba Ozukum,Syiemlieh, Ibanphylla,Lal, Ram A.
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p. 2969 - 2985
(2017/10/07)
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- Azolylthioacetamides as a potent scaffold for the development of metallo-β-lactamase inhibitors
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In an effort to develop new inhibitors of metallo-β-lactamases (MβLs), twenty-eight azolylthioacetamides were synthesized and assayed against MβLs. The obtained benzimidazolyl and benzioxazolyl substituted 1–19 specifically inhibited the enzyme ImiS, and 10 was found to be the most potent inhibitor of ImiS with an IC50 value of 15 nM. The nitrobenzimidazolyl substituted 20–28 specifically inhibited NDM-1, with 27 being the most potent inhibitor with an IC50 value of 170 nM. Further studies with 10, 11, and 27 revealed a mixed inhibition mode with competitive and uncompetitive inhibition constants in a similar range as the IC50 values. These inhibitors resulted in a 2–4-fold decrease in imipenem MIC values using E. coli cells producing ImiS or NDM-1. While the source of uncompetitive (possibly allosteric) inhibition remains unclear, docking studies indicate that 10 and 11 may interact orthosterically with Zn2 in the active site of CphA, while 27 could bridge the two Zn(II) ions in the active site of NDM-1 via its nitro group.
- Xiang, Yang,Chang, Ya-Nan,Ge, Ying,Kang, Joon S.,Zhang, Yi-Lin,Liu, Xiao-Long,Oelschlaeger, Peter,Yang, Ke-Wu
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supporting information
p. 5225 - 5229
(2017/11/13)
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- A toolbox for controlling the properties and functionalisation of hydrazone-based supramolecular hydrogels
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In recent years, we have developed a low molecular weight hydrogelator system that is formed in situ under ambient conditions through catalysed hydrazone formation between two individually non-gelating components. In this contribution, we describe a molecular toolbox based on this system which allows us to (1) investigate the limits of gel formation and fine-tuning of their bulk properties, (2) introduce multicolour fluorescent probes in an easy fashion to enable high-resolution imaging, and (3) chemically modify the supramolecular gel fibres through click and non-covalent chemistry, to expand the functionality of the resultant materials. In this paper we show preliminary applications of this toolbox, enabling covalent and non-covalent functionalisation of the gel network with proteins and multicolour imaging of hydrogel networks with embedded mammalian cells and their substructures. Overall, the results show that the toolbox allows for on demand gel network visualisation and functionalisation, enabling a wealth of applications in the areas of chemical biology and smart materials.
- Poolman, Jos M.,Maity, Chandan,Boekhoven, Job,Van Der Mee, Lars,Le Sage, Vincent A.A.,Groenewold, G.J. Mirjam,Van Kasteren, Sander I.,Versluis, Frank,Van Esch, Jan H.,Eelkema, Rienk
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supporting information
p. 852 - 858
(2016/02/05)
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- Synthesis and characterization of heterotrinuclear bis(μ2- chlorido)dicopper (II) mono zinc(II) complexes derived from succinoyldihydrazones
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Three new zinc (II)-copper (II) heterometallic trinuclear complexes of the composition [ZnCu2(Ln)(μ2-Cl) 2(H2O)6]×2H2O (H 4Ln = H4L1, H4L 2, H4L3) have been synthesized from substituted succinoyldihydrazones (H4Ln) in methanol medium. The composition of the complexes has been established on the basis of data obtained from analytical, mass spectral studies and molecular weight determinations in DMSO. The structure of the ligand H4L2 has been established by X-ray crystallography. The structure of the complexes has been discussed in the light of molar conductance, magnetic moment, electronic, EPR, IR and FT-IR spectral studies. The molar conductance values for the complexes fall in the region 1.2-1.7 ohm-1 cm2 mol-1 in DMSO solution indicating that all of these are non-electrolyte. The magnetic moment values suggest weak M-M interaction in the structural unit of the complexes. The dihydrazone ligand is present in enol form in all of the complexes. Copper centre has tetragonally distorted octahedral stereochemistry. The EPR parameters of the complexes indicate that the copper centre has doublet state as the ground state. The electron transfer reactions of the complexes have been investigated by cyclic voltammetry.
- Borthakur, Rosmita,Kumar, Arvind,Lal
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supporting information
p. 94 - 101
(2013/10/01)
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- Design and synthesis of phenolic hydrazide hydrazones as potent poly(ADP-ribose) glycohydrolase (PARG) inhibitors
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Poly(ADP-ribose) polymerase (PARP) and poly(ADP-ribose) glycohydrolase (PARG) are enzymes responsible for catalyzing the formation and degradation of poly(ADP-ribose) (PAR) polymers, respectively. Activation of PARP has been shown to be involved in cell death induced by genotoxic stimuli. On the other hand, genetic disruption of PARG also leads to increased level of cell death by accumulation of PAR. Unlike PARP, where significant medicinal effort has been expended to identify potent inhibitors, PARG has been insufficiently investigated as a molecular therapeutic target. In this study, we report the design, synthesis, and biological evaluation of phenolic hydrazide hydrazones as potent PARG inhibitors. Compounds 3d, 3e, 5d, 5e, 8a, 8b and 8c showed their ability to inhibit the catalytic activity of PARG in vitro with IC50 values of 1.0, 2.1, 3.1, 3.2, 3.1, 2.8 and 1.6 μM, respectively.
- Islam, Rafiqul,Koizumi, Fumiaki,Kodera, Yasuo,Inoue, Kengo,Okawara, Tadashi,Masutani, Mitsuko
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p. 3802 - 3806
(2014/09/16)
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- Synthesis, characterization and electrochemical properties of bis(μ2-perchlorato)tricopper(ii) complexes derived from succinoyldihydrazones
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Three new homotrimetallic copper(ii) complexes ([Cu3(L n)(ClO4)2(H2O)m] with H4Ln = H4L1 - H4L 3, m = 0, 3) have been synthesized from substituted succinoyldihydrazones (H4Ln) in methanol. The composition of the complexes has been established on the basis of data obtained from analytical and mass spectral studies and molecular weight determination in DMSO. The structure of the complexes has been discussed in the light of molar conductance, magnetic moment data and electronic, EPR, IR and FT-IR spectral studies. The molar conductance values for the complexes in the region of 1.2-1.7 Ω-1 cm2 mol-1 in DMSO indicate that the complexes are nonelectrolytes. The magnetic moment values for the complexes suggest considerable metal-metal interaction in the structural unit of the complexes. Copper centres have square planar and square pyramidal stereochemistry. The EPR parameters of complexes 1 and 3 indicate that the copper centre has a doublet ground state, while for complex 2, the ground state is a mixture of both doublet and quartet states. Electron transfer reactions of the complexes have been investigated by cyclic voltammetry. The Royal Society of Chemistry 2013.
- Borthakur,Kumar,Lemtur,Lal
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p. 15139 - 15147
(2013/09/02)
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- Thermoresponsive dynamic covalent single-chain polymer nanoparticles reversibly transform into a hydrogel
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To gel and back: Polymer nanoparticles can be reversibly transformed into a chemically cross-linked hydrogel. This transformation is triggered by the application of heat, which causes the polymer chains to aggregate, and the dynamic nature of the covalent cross-linking serves to reorganize the polymer chains into a hydrogel network. Copyright
- Whitaker, Daniel E.,Mahon, Clare S.,Fulton, David A.
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supporting information
p. 956 - 959
(2013/02/26)
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- Synthesis of 2-substituted-1,3,4-oxadiazoles
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Diethylsuccinate on reaction with hydrazine hydrate gave succinohydrazide (1) which on further treatment with carbon disulfide, aromatic aldehydes and cynogen bromide yielded 2-substituted-1,3,4-oxadiazole derivatives (2,3,4) respectively. The structures of the compounds have been elucidated on the basis of spectral analysis.
- Dabholkar, Vijay V.,Bhusari, Nitin V.
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p. 293 - 294
(2013/09/24)
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- Synthesis and antibacterial studies of a new series of 1,2-bis(1,3,4- oxadiazol-2-yl)ethanes and 1,2-bis(4-amino-1,2,4-triazol-3-yl)ethanes
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The acylhydrazones 3, obtained by the treatment of succinic acid dihydrazide 2 with furfural, nitrofurfuraldehydediacetate and substituted arylfurfurals, on oxidative cyclization with bromine in acetic acid yielded 1,2-bis(1,3,4-oxadiazol-2-yl)ethanes 4 which are further converted into 1,2- bis(4-amino-1,2,4-triazol-3-yl)ethanes 5 with hydrazine hydrate. The newly synthesised compounds are characterised by analytical, IR, NMR and mass spectral data. Most of the newly synthesised compounds have been found to be active against both Gram positive and Gram negative bacteria at less than 6 μg/mL concentration. (C) 2000 Editions scientifiques et medicales Elsevier SAS.
- Holla, B. Shivararna,Gonsalves, Richard,Shenoy, Shalini
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p. 267 - 271
(2007/10/03)
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- Enzymatic hydrazinolysis of diesters and synthesis of N-aminosuccinimide derivatives
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Selective hydrazinolysis of diesters is catalyzed by PS lipase. This enzyme is an efficient catalyst for the preparation of N-aminosuccinimide derivatives.
- Astorga,Rebolledo,Gotor
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p. 287 - 289
(2007/10/02)
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- Synthesis and Characterization of Nitrato and Acetato Complexes of Dioxouranium(VI) with Disalicylaldehyde Acyl Hydrazones
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Dioxouranium(VI) complexes of disalicylaldehyde oxaloyldihydrazone (H4A2), malonoyldihydrazone (H4B2), succinoyldihydrazone (H4C2), glutaroyldihydrazone (H4D2), adipoyldihydrazone (H4E2) and phthaloyldihydrazone (H4F2) have been synthesized from the reaction of uranyl nitrate hexahydrate and uranyl acetate dihydrate with the title ligands in alcoholic medium.The complexes have the compositions .2H2O and .C2H5OH where H4L2 = H4A2, H4B2, H4C2, H4D2, H4E2 and H4F2.The complexes have been characterized on the basis of elemental analyses, TGA, DTA, molar conductance, infrared and Raman spectral data.
- Das, S.,Lal, R. A.
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p. 225 - 230
(2007/10/02)
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