- N,N′-diethyl and N-ethyl,N′-methyl glyoxal-bridged cyclams: synthesis, characterization, and bleaching activities of the corresponding Mn(II) complexes
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The synthesis and characterization of N,N′-diethyl (L-Et,Et) and N-ethyl,N′-methyl (L-Et,Me) glyoxal-bridged cyclam ligands are described, together with the X-ray crystal structure of the complex [MnCl2(L-Et,Me)]. Bleaching of morine in the presence of hydrogen peroxide by the corresponding Mn catalysts [MnCl2(L-Et,Et)], [MnCl2(L-Et,Me)] and [MnCl2(L-Me,Me)] has been studied in aqueous solution at three different pH values (8.0, 8.75, and 9.0). The results clearly show that increasing pH has a different effect on the three catalysts, and that the dimethyl derivative is by far the most active.
- Di Mauro, Giovanni,Annunziata, Alfonso,Cucciolito, Maria Elena,Lega, Matteo,Resta, Stefano,Tuzi, Angela,Ruffo, Francesco
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- Bifunctional cyclam-based ligands with phosphorus acid pendant moieties for radiocopper separation: Thermodynamic and kinetic
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Two macrocyclic ligands based on cyclam with trans-disposed N-methyl and N-(4-aminobenzyl) substituents as well as two methylphosphinic (H2L1) or methylphosphonic (H4L2) acid pendant arms were synthesised and investigated in solution. The ligands form stable complexes with transition metal ions. Both ligands show high thermodynamic selectivity for divalent copper over nickel(II) and zinc(II)-K(CuL) is larger than K(Ni/ZnL) by about seven orders of magnitude. Complexation is significantly faster for the phosphonate ligand H4L2, probably due to the stronger coordination ability of the more basic phosphonate groups, which efficiently bind the metal ion in an "out-of-cage" complex and thus accelerate its "in-cage" binding. The rate of CuII complexation by the phosphinate ligand H2L1 is comparable to that of cyclam itself and its derivatives with noncoordinating substituents. Acid-assisted decomplexation of the copper(II) complexes is relatively fast (τ1/2 = 44 and 42 s in 1 M aq. HClO4 at 25 °C for H2L1 and H4L2, respectively). This combination of properties is convenient for selective copper removal/purification. Thus, the title ligands were employed in the preparation of ion-selective resins for radiocopper(II) separation. Glycidyl methacrylate copolymer beads were modified with the ligands through a diazotisation reaction. The separation ability of the modified polymers was tested with cold copper(II) and non-carrier-added 64Cu in the presence of a large excess of both nickel(II) and zinc(II). The experiments exhibited high overall separation efficiency leading to 60-70% recovery of radiocopper with high selectivity over the other metal ions, which were originally present in 900-fold molar excess. The results showed that chelating resins with properly tuned selectivity of their complexing moieties can be employed for radiocopper separation.
- Paúrová, Monika,Havlí?ková, Jana,Pospí?ilová, Aneta,Vetrík, Miroslav,Císa?oá, Ivana,Stephan, Holger,Pietzsch, Hans-Jürgen,Hruby, Martin,Hermann, Petr,Kotek, Jan
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- Fluorescent CXCR4 chemokine receptor antagonists: Metal activated binding
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The copper(ii) complex of a novel rhodamine-azamacrocycle conjugate binds to the CXCR4 chemokine receptor and competes effectively against anti-CXCR4 monoclonal antibodies. The copper macrocycle unit adopts a trans-II configuration in the solid state. The
- Khan, Abid,Silversides, Jon D.,Madden, Leigh,Greenman, John,Archibald, Stephen J.
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p. 416 - 418
(2007/10/03)
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- Synthesis and NMR characterisation of new cyclam-glyoxal diamides
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Cyclam-glyoxal diamides were synthesised by the reaction of 1,4,5,8-tetraazadecalin with two equivalents of methyl acrylate. The configuration of the four stereoisomers obtained was assigned using nuclear magnetic resonance (NMR) methods. The compounds we
- Antoine, Marine,Bernard, Helene,Kervarec, Nelly,Handel, Henri
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p. 552 - 555
(2007/10/03)
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- Bis-aminals: Efficient tools for bis-macrocycle synthesis
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Tetraazamacrocyclic bis-aminals prove to be excellent tools for the synthesis of symmetrical, dissymmetrical or functionalized bis-tetraazamacrocycles. The key feature of the process is the separation of insoluble mono- or bis-quaternary ammonium salts from solution during the course of the alkylation reaction.
- Le Baccon,Chuburu,Toupet,Handel,Soibinet,Dechamps-Olivier,Barbier,Aplincourt
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p. 1168 - 1174
(2007/10/03)
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- Synthesis and characterization of cross-bridged cyclams and pendant-armed derivatives and structural studies of their copper(II) complexes
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A series of 1,4,8,11-tetraazabicyclo[6.6.2]hexadecane ligands, including the parent compound, N,N′-dialkyl variants, and the first N,N′-di-pendant-arm derivatives have been synthesized by a short, efficient, and conceptually novel approach. Their copper(I
- Wong, Edward H.,Weisman, Gary R.,Hill, Daniel C.,Reed, David P.,Rogers, Mark E.,Condon, Jeffrey S.,Fagan, Maureen A.,Calabrese, Joseph C.,Lam, Kin-Chung,Guzei, Ilia A.,Rheingold, Arnold L.
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p. 10561 - 10572
(2007/10/03)
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- Synthesis and transition-metal complexes of new cross-bridged tetraamine ligands
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New cross-bridged tetraamine ligands (bicyclo[6.6.2], [6.5.2] and [5.5.2] systems) are synthesized; complexation of CuII and NiII demonstrates that the ligands coordinate selected metals in a cleft.
- Weisman, Gary R.,Wong, Edward H.,Hill, Daniel C.,Rogers, Mark E.,Reed, David P.,Calabrese, Joseph C.
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p. 947 - 948
(2007/10/03)
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- PREPARATION AND STEREOCHEMISTRY OF 1,4,8,11-TETRAAZAPERHYDROPYRENE DERIVATIVES FROM N,N'-BIS(3-AMINOPROPYL)ETHYLENEDIAMINE
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The reaction of N,N'-bis(3-aminopropyl)ethylenediamine (1) with glyoxal (2) in the presence of benzotriazole (3) afforded dibenzotriazoyltetraazaperhydropyrene (4), which was converted to polyazapolycycles (6), (13), (15), (16), and (19).The stereochemistry is discussed.
- Okawara, Tadashi,Takaishi, Hisashi,Okamoto, Yoshinari,Yamasaki, Tetsuo,Furukawa, Mitsuru
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p. 1023 - 1034
(2007/10/02)
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- TETRACYCLIC TETRAAMINES BY GLYOXAL-MACROCYCLIC TETRAAMINE CONDENSATION
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A series of new tetracyclic tetraamines have been synthesized in good to moderate yield by glyoxal-macrocyclic tetraamine condensation.
- Weisman, Gary R.,Ho, Suzzy C. H.,Johnson, Van
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p. 335 - 338
(2007/10/02)
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