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Mirta Rubčić - One of the best experts on this subject based on the ideXlab platform.
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Coordinating and supramolecular prospects of unsymmetrically substituted Carbohydrazides
New Journal of Chemistry, 2020Co-Authors: Edi Topić, Jana Pisk, Višnja Vrdoljak, Ivana Landripet, Maëlle Duguin, Ivica Đilović, Mirta RubčićAbstract:Unsymmetrically substituted Carbohydrazides, containing chelating o-hydroxyaryl and non-chelating pyridyl subunits were synthesized via two-step functionalization of Carbohydrazide. Anion binding and coordinative propensities of the compounds were tested in reactions with appropriate Mo(VI) species. Such procedures yielded four types of products: monomeric dioxomolybdenum(VI) complexes, dimeric and oligomeric/polymeric dioxomolybdenum(VI)-containing ensembles, hybrid hexamolybdate systems where the protonated ligand acts as cation and the hybrid hexamolybdate salts where the cation is the protonated form of the monomeric dioxomolybdenum(VI) complex. The solid-state structures of the compounds were elucidated by X-ray diffraction and infrared spectroscopy, while their thermal stability was inspected via thermogravimetric analysis and differential scanning calorimetry experiments. The behaviour of the ligands, monomeric, dimeric, and oligomeric/polymeric ensembles in DMSO solution was investigated by nuclear magnetic resonance. In the isolated materials, Carbohydrazide ligands adopt altogether four distinctive protonation forms: neutral, monoprotonated in the corresponding hexamolybdate salt, doubly deprotonated while forming {MoO2}2+ complexes, and neutral zwitterionic when shaping the hybrid salt. In all these structures the unsymmetrical Carbohydrazide framework retains robust conformation and geometry.
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Discrete and polymeric ensembles based on dinuclear molybdenum( vi ) building blocks with adaptive Carbohydrazide ligands: from the design to catalytic epoxidation
New Journal of Chemistry, 2020Co-Authors: Edi Topić, Jana Pisk, Višnja Vrdoljak, Dominique Agustin, Martin Jendrlin, Danijela Cvijanović, Mirta RubčićAbstract:Symmetrical disubstituted Carbohydrazides (H4L1–6) when reacted with [MoO2(acac)2] (in 1 : 2 molar ratio) afford the corresponding discrete complexes, [(MoO2)2L1,5,6(MeOH)2], [(MoO2)2L1,5,6(Im)2] (Im = imidazole), and/or polymeric ensembles, [(MoO2)2L1–6]n, depending on the reaction solvent, the ligand framework and the presence of ancillary coordinating species. In these assemblies, asymmetrical dimolybdenum(vi) entities, [(MoO2)2L1–6], wherein the corresponding Carbohydrazide acts as an adaptable two-compartment ligand offering ONO and ONN coordination environments, serve as the main building blocks. The solid-state structures of the obtained materials were elucidated via X-ray diffraction and infrared spectroscopy, whereas the behaviour of polymeric ensembles in DMSO-d6 solution was investigated by nuclear magnetic resonance. Thermal studies revealed that the discrete species transform to the corresponding polymeric ensembles upon heating, whereas upon grinding they either remain intact or afford their reactive and coordinatively unsaturated (pentacoordinated) counterparts. While the discrete methanol-based complexes have a comparable spatial arrangement of ancillary ligands, imidazole-based ones offer substantially different scenario which was addressed in detail via density functional theory calculations. Finally, the polymeric ensembles were shown to be efficient catalysts for cyclooctene epoxidation under eco-friendly conditions while employing aqueous tert-butyl hydroperoxide as an oxidant.
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Symmetrical disubstituted Carbohydrazides: From solid-state structures to cytotoxic and antibacterial activity
Journal of Molecular Structure, 2019Co-Authors: Mirta Rubčić, Jana Pisk, Katarina Pičuljan, Vladimir Damjanović, Jasna Lovrić, Višnja VrdoljakAbstract:Abstract A group of symmetrical disubstituted Carbohydrazides, namely 1,5-bis(2,3-dihydroxybenzylidene)Carbohydrazide, H4L1; 1,5-bis(2,4-dihydroxybenzylidene)Carbohydrazide, H4L2, and 1,5-bis(2-hydroxy-1-naphtalidene)Carbohydrazide, H4L3, were synthesized by combining conventional solution and mechanochemical approach. In the solid-state all three compounds possess the same tautomeric form; keto one with respect to the central carbamide fragment and the enol-imino form when considering their aldehyde residues, as established by single-crystal X-ray diffraction and IR spectroscopy. Similar situation is observed in DMSO solution, where compounds were investigated by NMR spectroscopy. In addition, divergent and complicated thermal behavior was established for all three compounds, as found by combined DSC and TG measurements. Finally, the obtained compounds (H4L1–H4L3) along with the previously published 1,5-bis(2–hydroxybenzylidene)Carbohydrazide (H4L4) and their parent Carbohydrazide (1,3-diaminourea; CH) were evaluated in vitro for their cytotoxic and antibacterial activity. All compounds proved to be noncytotoxic against HepG2 cells, while some of the examined Carbohydrazides showed only very weak activity against THP-1 cell line. None of the tested compounds showed antibacterial properties towards S. aureus, E. faecalis, E. coli and M. catarrhalis strain.
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NMR characterisation of 1, 5- bis(salicylidene)Carbohydrazide in solution and solid state
2015Co-Authors: Tomislav Jednačak, Mirta Rubčić, Predrag Novak, Janez Plavec, Primož Šket, Nives GalićAbstract:Carbohydrazide derived Schiff bases are higher urea homologues with interesting biological properties, which together with their reactivity, led to a number of laboratory and industrial applications. These compounds have been widely used as selective analytical reagents for ion binding, as precursors in the syntheses of nitrogen containing heterocycles and as multitopic ligands for the targeted construction of coordination systems with biological activity. They are usually prepared by the condensation reaction between Carbohydrazide and appropriate carbonyl compound. The structure of 1, 5- bis(salicylidene)Carbohydrazide (1) has been characterised by NMR spectroscopy in solution and solid state. As shown in Figure 1, this molecule might exist in several tautomeric forms and has a few reactive groups able to participate in both intra- and intermolecular hydrogen bonds. It has been demonstrated that the tautomer 1a is the dominant form in solution and in all solid phases. Significant deshielding and line-broadening of the signals corresponding to NH and OH protons have clearly indicated that both groups formed hydrogen bonds. Furthermore, the analysis of solid-state NMR spectra allowed the identification of five crystallographic forms of 1: three polymorphs (I, II and III) and two solvates (IV and V). The obtained results can further be exploited for better understanding the relationship between the structure, physico-chemical properties and bioactivity of Carbohydrazide derivatives.
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Multiple Solid Forms of 1,5-Bis(salicylidene)Carbohydrazide: Polymorph-Modulated Thermal Reactivity
Crystal Growth & Design, 2014Co-Authors: Mirta Rubčić, Janez Plavec, Nives Galić, Ivan Halasz, Tomislav Jednačak, Nenad Judaš, Primož Šket, Predrag NovakAbstract:1,5-Bis(salicylidene)Carbohydrazide, prepared by a condensation reaction of salicylaldehyde and Carbohydrazide, afforded a diversity of crystalline forms depending on crystallization conditions: three polymorphs (I, II, and III) and two solvates (IV and V). All solid phases comprise the same tautomer of the title compound, which bears the salicylidene residues in the enol-imino form and the carbamide fragment in the keto form, as established via X-ray crystallography, IR spectroscopy, and cross-polarization magic-angle spinning (CP MAS) NMR (13C and 1H). Conformations of 1,5-bis(salicylidene)Carbohydrazide molecules and their hydrogen-bonding patterns are similar for two polymorphs (II and III), while the third one (I) in this context differs significantly. Thermal analyses revealed that all phases undergo complicated degradation upon heating, yielding salicylideneazine, CO2, and N2 either directly or via intermediates. Relative phase stability was inspected mechanochemically and by solvent-mediated exper...
S. I. Bychkov - One of the best experts on this subject based on the ideXlab platform.
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Stripping of Pu and Tc from tributyl phosphate solutions with Carbohydrazide
Radiochemistry, 2012Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. N. Alekseenko, V. V. Bondin, S. I. BychkovAbstract:Stripping of Pu from 30% tributyl phosphate solutions with Carbohydrazide was studied. The degree of the Pu stripping drastically decreases with an increase in acidity and increases with an increase in the Carbohydrazide concentration and in temperature. The Pu(IV) reduction rate in the two-phase system is sufficiently high to perform the reductive stripping of Pu with Carbohydrazides both in mixer-settlers and in centrifugal extractors. Stripping of Tc at high phase ratio (O/W = 30) with Carbohydrazide, hydrazine, and U(IV) in a mixture with hydrazine was studied. At low acidity (
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stripping of pu and tc from tributyl phosphate solutions with Carbohydrazide
Radiochemistry, 2012Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. N. Alekseenko, V. V. Bondin, S. I. BychkovAbstract:Stripping of Pu from 30% tributyl phosphate solutions with Carbohydrazide was studied. The degree of the Pu stripping drastically decreases with an increase in acidity and increases with an increase in the Carbohydrazide concentration and in temperature. The Pu(IV) reduction rate in the two-phase system is sufficiently high to perform the reductive stripping of Pu with Carbohydrazides both in mixer-settlers and in centrifugal extractors. Stripping of Tc at high phase ratio (O/W = 30) with Carbohydrazide, hydrazine, and U(IV) in a mixture with hydrazine was studied. At low acidity (<1 M HNO3) and 30–35°C, Carbohydrazide allows more than 80% stripping of Tc from 30% TBP solutions even at high volume ratio of the phases.
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Reduction of Pu(IV) and Np(VI) with Carbohydrazide in nitric acid solution
Radiochemistry, 2012Co-Authors: V. I. Volk, V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. V. Bondin, S. I. Bychkov, E. Yu. Pavlyukevich, A. S. D’yachenkoAbstract:The reduction of Pu(IV) and Np(VI) with Carbohydrazide (NH2NH)2CO in 1–6 M HNO3 solutions was studied. The Pu(IV) reduction is described by a first-order rate equation with respect to Pu(IV). At [HNO3] ≥ 3 M, the reaction becomes reversible. The rate constants of the forward and reverse reactions were determined, and their activation energies were estimated. Neptunium(VI) is reduced to Np(V) at a high rate, whereas the subsequent reduction of Np(V) to Np(IV) is considerably slower and is catalyzed by Fe and Tc ions. The possibility of using Carbohydrazide for stabilizing desired combinations of Pu and Np valence states was examined.
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Oxidation of Carbohydrazide with nitric acid
Radiochemistry, 2012Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. I. Bychkov, V. V. BondinAbstract:The kinetics of Carbohydrazide oxidation with nitric acid in aqueous solutions was studied. In the range [HNO3] = 3–7 M, the reaction rate is described by the equation −d[(NH2NH)2CO]/dt = k[(NH2NH)2CO][HNO3] n , where n = 3.6 and 2.9 at 70 and 90°C, respectively. The constant k = (6.65 ± 0.23) × 10−4 l2.9 mol−2.9 h−1 at 90°C, and the activation energy of the reaction in 7 M HNO3 is 124 kJ mol−1. The Fe(III) and especially Tc(VII) ions considerably accelerate the reaction, whereas the uranyl ions accelerate it insignificantly. The reaction mechanism in which the reactive species oxidizing Carbohydrazide is nitronium ion NO 2 + was suggested.
K. N. Dvoeglazov - One of the best experts on this subject based on the ideXlab platform.
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Kinetics of Np(VI) reduction with Carbohydrazide in nitric acid
Radiochemistry, 2017Co-Authors: O. A. Zavalina, K. N. Dvoeglazov, E. Yu. Pavlyukevich, S. I. StepanovAbstract:The kinetics of the Np(VI) reduction with Carbohydrazide in nitric acid solutions was studied by spectrophotometry. The reaction rate increases with increasing Carbohydrazide concentration and temperature and decreases with increasing HNO_3 concentration. The reaction order with respect to Np, Carbohydrazide, and HNO_3 is 1, 1.15, and–1.35, respectively. The activation energy of the reaction is 85 kJ mol^–1.
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Kinetics of Pu(VI) reduction with Carbohydrazide in nitric acid
Radiochemistry, 2017Co-Authors: O. A. Zavalina, K. N. Dvoeglazov, E. Yu. PavlyukevichAbstract:The kinetics of the Pu(VI) reduction with Carbohydrazide in nitric acid solutions was studied by spectrophotometry. The reaction rate increases with increasing Carbohydrazide concentration and temperature and decreases with increasing HNO_3 concentration. The reaction order with respect to Pu, Carbohydrazide, and HNO_3 is 1, 2.3, and–3, respectively. The activation energy of the reaction is 111 kJ mol^–1. The final reduced Pu form is Pu(III), with Pu(V) being an intermediate.
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Reduction of Pu(IV) by Carbohydrazide in aqueous solutions and in two-phase systems with tributyl phosphate
Journal of Radioanalytical and Nuclear Chemistry, 2015Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. N. Alekseenko, L. N. PodrezovaAbstract:The possibility of using Carbohydrazide as a reducing agent for plutonium in Purex process was examined. Kinetics of the reaction between Pu(IV) and Carbohydrazide in HNO3 aqueous solution was studied spectrophotometrically, the rate law was established, and the rate constant and activation energy values were calculated. Plutonium stripping efficiency by Carbohydrazide as defined is higher in the two-phase system: 30 % TBP with Pu(IV) nitric acid aqueous solution, in the presence of glycine. A laboratory scale counter-current experiment performed with the use of simulated WWER-1000 SNF reprocessing solutions demonstrated the possibility of Carbohydrazide–glycine mixture using for plutonium concentrating back-extraction process.
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Stripping of Pu and Tc from tributyl phosphate solutions with Carbohydrazide
Radiochemistry, 2012Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. N. Alekseenko, V. V. Bondin, S. I. BychkovAbstract:Stripping of Pu from 30% tributyl phosphate solutions with Carbohydrazide was studied. The degree of the Pu stripping drastically decreases with an increase in acidity and increases with an increase in the Carbohydrazide concentration and in temperature. The Pu(IV) reduction rate in the two-phase system is sufficiently high to perform the reductive stripping of Pu with Carbohydrazides both in mixer-settlers and in centrifugal extractors. Stripping of Tc at high phase ratio (O/W = 30) with Carbohydrazide, hydrazine, and U(IV) in a mixture with hydrazine was studied. At low acidity (
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stripping of pu and tc from tributyl phosphate solutions with Carbohydrazide
Radiochemistry, 2012Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. N. Alekseenko, V. V. Bondin, S. I. BychkovAbstract:Stripping of Pu from 30% tributyl phosphate solutions with Carbohydrazide was studied. The degree of the Pu stripping drastically decreases with an increase in acidity and increases with an increase in the Carbohydrazide concentration and in temperature. The Pu(IV) reduction rate in the two-phase system is sufficiently high to perform the reductive stripping of Pu with Carbohydrazides both in mixer-settlers and in centrifugal extractors. Stripping of Tc at high phase ratio (O/W = 30) with Carbohydrazide, hydrazine, and U(IV) in a mixture with hydrazine was studied. At low acidity (<1 M HNO3) and 30–35°C, Carbohydrazide allows more than 80% stripping of Tc from 30% TBP solutions even at high volume ratio of the phases.
V. N. Alekseenko - One of the best experts on this subject based on the ideXlab platform.
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Reduction of Pu(IV) by Carbohydrazide in aqueous solutions and in two-phase systems with tributyl phosphate
Journal of Radioanalytical and Nuclear Chemistry, 2015Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. N. Alekseenko, L. N. PodrezovaAbstract:The possibility of using Carbohydrazide as a reducing agent for plutonium in Purex process was examined. Kinetics of the reaction between Pu(IV) and Carbohydrazide in HNO3 aqueous solution was studied spectrophotometrically, the rate law was established, and the rate constant and activation energy values were calculated. Plutonium stripping efficiency by Carbohydrazide as defined is higher in the two-phase system: 30 % TBP with Pu(IV) nitric acid aqueous solution, in the presence of glycine. A laboratory scale counter-current experiment performed with the use of simulated WWER-1000 SNF reprocessing solutions demonstrated the possibility of Carbohydrazide–glycine mixture using for plutonium concentrating back-extraction process.
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Stripping of Pu and Tc from tributyl phosphate solutions with Carbohydrazide
Radiochemistry, 2012Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. N. Alekseenko, V. V. Bondin, S. I. BychkovAbstract:Stripping of Pu from 30% tributyl phosphate solutions with Carbohydrazide was studied. The degree of the Pu stripping drastically decreases with an increase in acidity and increases with an increase in the Carbohydrazide concentration and in temperature. The Pu(IV) reduction rate in the two-phase system is sufficiently high to perform the reductive stripping of Pu with Carbohydrazides both in mixer-settlers and in centrifugal extractors. Stripping of Tc at high phase ratio (O/W = 30) with Carbohydrazide, hydrazine, and U(IV) in a mixture with hydrazine was studied. At low acidity (
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stripping of pu and tc from tributyl phosphate solutions with Carbohydrazide
Radiochemistry, 2012Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. N. Alekseenko, V. V. Bondin, S. I. BychkovAbstract:Stripping of Pu from 30% tributyl phosphate solutions with Carbohydrazide was studied. The degree of the Pu stripping drastically decreases with an increase in acidity and increases with an increase in the Carbohydrazide concentration and in temperature. The Pu(IV) reduction rate in the two-phase system is sufficiently high to perform the reductive stripping of Pu with Carbohydrazides both in mixer-settlers and in centrifugal extractors. Stripping of Tc at high phase ratio (O/W = 30) with Carbohydrazide, hydrazine, and U(IV) in a mixture with hydrazine was studied. At low acidity (<1 M HNO3) and 30–35°C, Carbohydrazide allows more than 80% stripping of Tc from 30% TBP solutions even at high volume ratio of the phases.
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Reduction of Pu(IV) and Np(VI) with Carbohydrazide in nitric acid solution
Radiochemistry, 2012Co-Authors: V. I. Volk, V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. V. Bondin, S. I. Bychkov, E. Yu. Pavlyukevich, A. S. D’yachenkoAbstract:The reduction of Pu(IV) and Np(VI) with Carbohydrazide (NH2NH)2CO in 1–6 M HNO3 solutions was studied. The Pu(IV) reduction is described by a first-order rate equation with respect to Pu(IV). At [HNO3] ≥ 3 M, the reaction becomes reversible. The rate constants of the forward and reverse reactions were determined, and their activation energies were estimated. Neptunium(VI) is reduced to Np(V) at a high rate, whereas the subsequent reduction of Np(V) to Np(IV) is considerably slower and is catalyzed by Fe and Tc ions. The possibility of using Carbohydrazide for stabilizing desired combinations of Pu and Np valence states was examined.
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Oxidation of Carbohydrazide with nitric acid
Radiochemistry, 2012Co-Authors: V. N. Alekseenko, V. I. Marchenko, K. N. Dvoeglazov, V. I. Volk, S. I. Bychkov, V. V. BondinAbstract:The kinetics of Carbohydrazide oxidation with nitric acid in aqueous solutions was studied. In the range [HNO3] = 3–7 M, the reaction rate is described by the equation −d[(NH2NH)2CO]/dt = k[(NH2NH)2CO][HNO3] n , where n = 3.6 and 2.9 at 70 and 90°C, respectively. The constant k = (6.65 ± 0.23) × 10−4 l2.9 mol−2.9 h−1 at 90°C, and the activation energy of the reaction in 7 M HNO3 is 124 kJ mol−1. The Fe(III) and especially Tc(VII) ions considerably accelerate the reaction, whereas the uranyl ions accelerate it insignificantly. The reaction mechanism in which the reactive species oxidizing Carbohydrazide is nitronium ion NO 2 + was suggested.
Hideyuki Ito - One of the best experts on this subject based on the ideXlab platform.
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quinolone analogs 11 synthesis of novel 4 quinolone 3 Carbohydrazide derivatives with antimalarial activity
Journal of Heterocyclic Chemistry, 2012Co-Authors: Yoshihisa Kurasawa, Kiminari Yoshida, Naoki Yamazaki, Eisuke Kaji, Kenji Sasaki, Yoshito Zamami, Yasuhiro Sakai, Takatoshi Fujii, Hideyuki ItoAbstract:The reaction of the 6-substituted 1-methyl-4-quinolone-3-carboxylates with hydrazine hydrate gave the 3-Carbohydrazides , respectively, whose reaction with 2-, 3-, and 4-pyridinecarbaldehydes afforded the 3-(N2-pyridylmethylene)Carbohydrazides and . The Curtius rearrangement of compound provided the N,N′-bis(4-quinolon-3-yl)urea presumably via the 3-carboazide 11 and then 3-isocyanate 12. Compounds , , and were found to possess antimalarial activity from the in vitro screening data. J. Heterocyclic Chem.,(2011).
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Quinolone analogs 11: Synthesis of novel 4‐quinolone‐3‐Carbohydrazide derivatives with antimalarial activity
Journal of Heterocyclic Chemistry, 2011Co-Authors: Yoshihisa Kurasawa, Kiminari Yoshida, Naoki Yamazaki, Eisuke Kaji, Kenji Sasaki, Yoshito Zamami, Yasuhiro Sakai, Takatoshi Fujii, Hideyuki ItoAbstract:The reaction of the 6-substituted 1-methyl-4-quinolone-3-carboxylates with hydrazine hydrate gave the 3-Carbohydrazides , respectively, whose reaction with 2-, 3-, and 4-pyridinecarbaldehydes afforded the 3-(N2-pyridylmethylene)Carbohydrazides and . The Curtius rearrangement of compound provided the N,N′-bis(4-quinolon-3-yl)urea presumably via the 3-carboazide 11 and then 3-isocyanate 12. Compounds , , and were found to possess antimalarial activity from the in vitro screening data. J. Heterocyclic Chem.,(2011).