- The role of the capping bond effect on pyclen natY3+/90Y3+ chelates: Full control of the regiospecific: N -functionalization makes the difference
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Thanks to a smart regiospecific N-functionalization, a pyclen based ligand bearing one picolinate and two acetate arms organized in a dissymmetric manner was synthesized for Y3+ complexation, and compared to its symmetric analogue. The nature of the capping bonds around the metal coordination environment has a dramatic effect on the properties of the chelate, the natY3+ and 90Y3+ dissymmetric derivatives presenting enhanced thermodynamic stability and kinetic inertness.
- Le Fur, Mariane,Beyler, Maryline,Molnár, Eniko,Fougère, Olivier,Esteban-Gómez, David,Tircsó, Gyula,Platas-Iglesias, Carlos,Lepareur, Nicolas,Rousseaux, Olivier,Tripier, Rapha?l
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Read Online
- Catalytic Selective Oxidation of Primary and Secondary Alcohols Using Nonheme [Iron(III)(Pyridine-Containing Ligand)] Complexes
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The selective oxidation of different primary and secondary alcohols to carbonyl compounds by hydrogen peroxide was found to be catalyzed in conversion ranging from good to excellent by an iron(III) complex of a pyridine-containing macrocyclic ligand (Pc-L), without the need of any additive. The choice of the counteranion (Cl, Br, OTf) appeared to be of fundamental importance and the best results in terms of selectivity (up to 99 %) and conversion (up to 98 %) were obtained using the well-characterized [Fe(III)(Br)2(Pc-L)]Br complex, 4c. Magnetic moments in solid-state, also confirmed in solution ([D6]DMSO) by Evans NMR method, were calculated and point out to an iron metal center in the high spin state of 5/2. The crystal structure shows that the iron(III) center is coordinated by the four nitrogen atoms of the macrocycle and two bromide anions to form a distorted octahedral coordination environment. The catalytic oxidation of benzyl alcohol in acetonitrile was found occurring with better conversions and selectivities than in other solvents. The reaction proved to be quite general, tolerating aromatic and aliphatic alcohols, although very low yields were obtained for terminal aliphatic alcohols. Preliminary mechanistic studies are in agreement with a catalytic cycle promoted by a high-spin iron complex.
- Caselli, Alessandro,Gallo, Emma,Panza, Nicola,Rizzato, Silvia,Tseberlidis, Giorgio,di Biase, Armando
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p. 6635 - 6644
(2020/10/30)
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- Seven coordinate Co(ii) and six coordinate Ni(ii) complexes of an aromatic macrocyclic triamide ligand as paraCEST agents for MRI
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We are reporting Co(ii) and Ni(ii) complexes of a pyridine containing aromatic macrocyclic triamide ligand, 3,6,9,15-tetraazabicyclo(9.3.1)pentadeca-1(15),11,13-triene-3,6,9-triacetamide (TPTA), as paramagnetic chemical exchange saturation transfer (paraCEST) MRI contrast agents. The synthesis and characterization of TPTA and its complexes are reported. The solution chemistry and solid-state structure of Co(ii) and Ni(ii) complexes are studied. Crystallographic data show that the [Co(TPTA)]·Cl2·2H2O complex (seven-coordinate, all four N atoms of ring and three amide O atoms) has a distorted pentagonal bipyramidal geometry, however the [Ni(TPTA)Cl]·Cl·0.25H2O complex (six-coordinate, all four N atoms of the ring, one amide O and one chloride ion) adopts a distorted octahedral geometry. Notably the two pendent amide arms are not coordinated in the [Ni(TPTA)Cl]+ complex and one chloride ion fulfils its sixth coordination. The CEST effect of [Co(TPTA)]2+ and [Ni(TPTA)Cl]+ amide protons is observed at 57 ppm and 78 ppm downfield of the bulk water proton respectively in a buffer solution containing 20 mM N-(2-hydroxyethyl)piperazine-N′-ethanesulfonic acid and 100 mM NaCl at pH 7.4 at 37 °C on a 9.4 T NMR spectrometer. The effects of CEST intensity and exchange rate constant with variation of pH of the solution were studied. The CEST effect and exchange rate constant for the amide protons of the [Co(TPTA)]2+ complex have been monitored in HEPES buffer, fetal bovine serum (FBS), rabbit serum and 4% agarose gel (w/w). The stability of the [Co(TPTA)]2+ complex in aqueous solution towards oxidation was verified by cyclic voltammetry measurement. The stability of [Co(TPTA)]2+ has further been monitored in the presence of biologically relevant ions including HPO42-, CO32-, and Zn2+ and under acidic conditions.
- Pradhan, Rabindra N.,Chakraborty, Subhayan,Bharti, Pratibha,Kumar, Janesh,Ghosh, Arindam,Singh, Akhilesh K.
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p. 8899 - 8910
(2019/06/24)
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- Cobalt hydroperoxo complex, preparation method thereof, and active oxygen carrier comprising the same
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The present invention relates to a cobalt hydroperoxo complex, a production method thereof, and an active oxygen carrier including the same. According to the present invention, the cobalt hydroperoxo complex oxidizes P of triphenylphosphine and S of thioanisole through oxygen atom transfer (OAT) with excellent reactivity at a subzero temperature, and also shows reaction-selective effects without inducing hydrogen atom transfer (HAT) to xanthene and cyclohexadiene.COPYRIGHT KIPO 2018
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Paragraph 0113-0115
(2019/01/25)
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- Method for preparing 1,4,7,10-tetraaza-2,6-pyridinophane
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The invention relates to a novel method for preparing 1,4,7,10-tetraaza-2,6-pyridinophane. 2,6-dimethylamino pyridine serving as a raw material is subjected to amino protection through o-/p-nitrobenzenesulfonyl and reacts with N,N-di(2-chloroethyl)-o-/p-n
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Paragraph 0042
(2017/08/28)
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- A zinc-tetraazatricyclo complex, a preparing method thereof and applications of the complex in antitumor drugs
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A zinc-tetraazatricyclo complex, a preparing method thereof and applications of the complex in antitumor drugs are disclosed. The structure formula of the complex CHN5O3ZnCl(L-Zn) is shown as a formula 1. The Zn-tetraazatricyclo complex has good DNA hydrolysis and cutting activity. Influences of the Zn-tetraazatricyclo complex on cell propagation of cancer cell strains, normal cell strains and cell strains having drug resistance to cis-platinum are researched by applying an MTT process and by adopting the cis-platinum as a positive contrast medicine, and results show that the a cell propagation inhibiting function of the Zn-tetraazatricyclo complex is better than that of the cis-platinum, and toxicity of the complex to normal liver cells is slightly lower than that to liver cancer cells. In-vivo tumor proliferation inhibiting activity of the Zn-tetraazatricyclo complex is researched by utilizing an ICR mouse model with subcutaneous implantation of H22 liver cancer cells, and results show that the Zn-tetraazatricyclo complex has good tumor proliferation inhibiting activity.
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Paragraph 0053; 0054
(2017/04/28)
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- Reactivity of a Cobalt(III)-Hydroperoxo Complex in Electrophilic Reactions
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The reactivity of mononuclear metal-hydroperoxo adducts has fascinated researchers in many areas due to their diverse biological and catalytic processes. In this study, a mononuclear cobalt(III)-peroxo complex bearing a tetradentate macrocyclic ligand, [C
- Shin, Bongki,Sutherlin, Kyle D.,Ohta, Takehiro,Ogura, Takashi,Solomon, Edward I.,Cho, Jaeheung
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supporting information
p. 12391 - 12399
(2016/12/14)
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- Exceedingly fast oxygen atom transfer to olefins via a catalytically competent nonheme iron species
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The reaction of [Fe(CF3SO3)2(PyNMe3)] with excess peracetic acid at -40 °C leads to the accumulation of a metastable compound that exists as a pair of electromeric species, [FeIII(OOAc)(PyNMe3)]2+ and [FeV(O)(OAc)(PyNMe3)]2+, in fast equilibrium. Stopped-flow UV/Vis analysis confirmed that oxygen atom transfer (OAT) from these electromeric species to olefinic substrates is exceedingly fast, forming epoxides with stereoretention. The impact of the electronic and steric properties of the substrate on the reaction rate could be elucidated, and the relative reactivities determined for the catalytic oxidations could be reproduced by kinetic studies. The observed fast reaction rates and high selectivities demonstrate that this metastable compound is a truly competent OAT intermediate of relevance for nonheme iron catalyzed epoxidations. A metastable nonheme iron-oxygen species undergoes exceedingly fast oxygen atom transfer (OAT) to olefins, providing epoxides with stereoretention. The reaction rates determined by stopped-flow UV/Vis analysis are in good agreement with the relative reactivities of different olefins, confirming that this compound is a competent OAT intermediate of relevance to nonheme iron catalyzed epoxidations.
- Serrano-Plana, Joan,Aguinaco, Almudena,Belda, Raquel,García-Espa?a, Enrique,Basallote, Manuel G.,Company, Anna,Costas, Miquel
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supporting information
p. 6310 - 6314
(2016/05/24)
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- A mononuclear Mn2+ complex based on a novel tris-(ethyl acetate) pendant-armed tetraazamacrocycle: Effect of pyridine on self-assembly and weak interactions
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A novel pyridine containing tetraazamacrocycle 3,6,9,15-tetraazabicyclo[9. 3.1]pentadeca-1(15),11,13-triene-3,6,9-triacetic acid ethyl ester (1) and its mononuclear Mn2+ complex (2) have been prepared. Pyridine induced the π-π stacking of [Mn1]2+ and provided donors for nonclassical CH...O hydrogen bonding as well. In the solid state of 2, the combination of π-π interactions and hydrogen bonding constructed a 3D crystal structure and thus formed pairs of interacting mononuclear complexes that mediated weak magnetic exchanges between the Mn2+ ions. Meanwhile, self-assembly of 2 dissociated in the aqueous solution, and the effect of pyridine on the nature of DNA binding with 2 have also been investigated.
- Wen, Jinghan,Geng, Zhirong,Yin, Yuxin,Wang, Zhilin
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scheme or table
p. 16 - 20
(2012/08/27)
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- Regioselective synthesis of N-functionalized 12-membered azapyridinomacrocycles bearing trialkylcarboxylic acid side chains
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Selective protection of primary amine moieties of diethylenetriamine by 2-nitrophenylsulfonyl chloride followed by alkylation of the central N atom generates functionalized disulfonamide building blocks. When reacted with 2,6-bis(bromomethyl)pyridine following the Richman-Atkins methodology, such compounds yield the corresponding pyridine-containing azamacrocycles. Smooth removal of the N-sulfonyl groups provides versatile azamacrocyclic intermediates with transannular secondary amine functions. Subsequent N-alkylation regioselectively leads to tri N-functionalized 12-membered azapyridinomacrocycles bearing a sequence of N-acetate and N-propionate side chains.
- Siaugue, Jean-Michel,Segat-Dioury, Fabienne,Sylvestre, Isabelle,Favre-Réguillon, Alain,Foos, Jacques,Madic, Charles,Guy, Alain
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p. 4713 - 4718
(2007/10/03)
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- A highly chemoselective protection and activation of primary amines in polyamine
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Functionalization of polyamines containing both primary and secondary amine moieties could be achieved with the use of 2-nitrobenzenesulfonyl chloride. In the presence of a secondary amine, the primary amine groups are selectively transformed into the cor
- Favre-Réguillon, Alain,Segat-Dioury, Fabienne,Nait-Bouda, Lalou,Cosma, Camlia,Siaugue, Jean-Michel,Foos, Jacques,Guy, Alain
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p. 868 - 870
(2007/10/03)
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- Diethoxyphosphoryl as a protecting-activating group in the synthesis of polyazacyclophanes
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The fully diethoxyphosphoryl(Dep)-protected polyamines 1b-3b were prepared from the corresponding polyamines with 'diethyl phosphite' (= diethyl phosphonate) and CCl4 in a solid base/organic liquid two-phase system in the presence of Bu4NBr as phase-transfer catalyst. Subsequent phase-transfer-catalyzed alkylation of phosphoramidates 1b-3b with bis(chloromethyl)arenes 5-8 in the presence of Bu4N(HSO4) followed by deprotection gave good yields of polyazacyclophanes 9a-16a.
- Chellini, Andrea,Pagliarin, Roberto,Giovenzanna, Giovanni B.,Palmisano, Giovanni,Sisti, Massimo
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p. 793 - 800
(2007/10/03)
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- Bicyclopol yazamacrocyclophosphonic acid complexes for use as contrast agents
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Bicyclopolyazamacrocyclophosphonic acid compounds are disclosed which may form inert complexes with Gd, Mn or Fe ions. The overall charge of the complex can be varied to alter the in vivo biolocalization. Such complexes can be covalently attached to an antibody, antibody fragment or other biologically active molecule to form conjugates. The complexes and conjugates are useful as contrast agents for diagnostic purposes.
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- Polyazamacrocyclofluoromonoalkylphosphonic acids, and their complexes, for use as contrast agents
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Polyazamacrocyclofluoromonoalkylphosphonic acid compounds are disclosed which form inert complexes with Gd, Mn, Fe or La ions. The complexes are useful as contrast agents for diagnostic purposes.
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- Bicyclopolyazamacrocyclophosphonic acid complexes for use as radiopharmaceuticals
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Complexes of bicyclopolyazamacrocyclophosphonic acid compounds with a metal ion, e.g. 153 Sm, 177 Lu, 159 Gd, 149 Pm, 140 La, 175 Yb, 166 Ho, 90 Y, 47 Sc, 186 Re, 188 Re, 142 Pr, 99m Tc, 67 Ga, 68 Ga, 105 Rh, 97 Ru, 111 In, 113m In or 115m In ion, are disclosed. The complexes can be covalently attached to a biologically active molecule, e.g. an antibody or antibody fragment, to form conjugates. The complexes and conjugates are useful as radiopharmaceutical agents for therapy and/or diagnostic purposes.
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