New side-bridged bismacrocycles and cross-bridged macrotricycles. Syntheses and Cu(ii) complexation study

Bernier, Nicolas; Allali, Mustapha; Tripier, Raphaël; Conan, Françoise; Patinec, Véronique; Develay, Stéphanie; Baccon, Michel Le; Handel, Henri

doi:10.1039/b515150c

Cited by 24 publications

(41 citation statements)

References 37 publications

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“…[16][17][18][19] As shown in Scheme 2, the studied ligand 6 consists in three DO3A moieties linked with a mesitylenyl center and is obtained following an easy route involving the bisaminal methodology of tetraazacycloalkanes. 20- 23 In a first step, the macrocyclic bisaminal 2 is obtained by condensation of glyoxal with cyclen 1 as previously described.…”

Section: Synthesis Of the Ligandmentioning

confidence: 99%

“…The 17 O paramagnetic chemical shift experienced by water molecules directly bound to gadolinium ions is governed by the scalar or Fermi contact term. 29 At high temperatures (T > 322 K, 1000/T < 3.1 K -1 ) in the fast exchange regime the reduced chemical shift Dw r is directly given by the chemical shift of the bound water molecules, Dw m .…”

Section: H Nmrdmentioning

confidence: 99%

“…6 If we are not interested in detailed information about the electron spin relaxation and if we restrict the data analysis to medium to high magnetic fields the SBM approach gives reliable information on dynamic processes like water exchange rate constants and rotational correlation times for small to midsize complexes. 32 In a first step we fitted the 17 O relaxation rates and chemical shift data of both compounds together. We fixed the distance between Gd 3+ and the water oxygen, r GdO , to 2.5 Å .…”

Section: H Nmrdmentioning

confidence: 99%

“…From the fit we obtained for the exchange rate constant k ex 298 = 3.2 ¥ 10 7 s -1 and DH ‡ = 25.8 kJ mol -1 . A mean rotational correlation time t R 298 = 212 ps (E a = 19.7 kJ mol -1 ) has been calculated from the longitudinal 17 O spin relaxation.…”

Section: H Nmrdmentioning

confidence: 99%

“…In these separate fits we fixed the exchange rate constant and activation enthalpy to the values obtained from the 17 O data analysis. The water proton-Gd distance, r GdH , and parameters defining the outer sphere contribution to the 1 H relaxivity have been fixed to common values (Table 1).…”

Section: H Nmrdmentioning

confidence: 99%

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Synthesis, complexation and NMR relaxation properties of Gd3+ complexes of Mes(DO3A)3

et al. 2011

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Medium sized molecules endowed with multiple Gd 3+ complexes are efficient high magnetic field MRI contrast agents. The novel ligand Mes(DO3A) 3 , presenting three DO3A (1,4,7,10-tetraazacyclododecane-N,N¢,N¢¢-triacetatic acid) units grafted on the methyl positions of a central mesitylene (1,3,5-trimethylbenzene), has been synthesized. Designed as an MRI contrast agent, this ligand is complexed with Gd 3+ and its efficiency is characterized by variable field 1 H-NMR and variable temperature 17 O-NMR. The evaluation of the relaxation and paramagnetic chemical shift data allowed the identification of an undesired binuclear complex which is obtained by using the classical procedure for complexation as described in the literature. An intramolecular capping mechanism appears to be responsible for the failure to introduce a third Gd 3+ ion into the ligand. A new alternative method, based on pre-complexation with Mg 2+ followed by transmetallation is described here and leads to the expected trinuclear Gd 3+ complex [Mes{Gd(DO3A)(H 2 O) 2 } 3 ]. The rate constants for the water exchange (k ex 298 = 32 ¥ 10 6 s -1 ) for the bi-and trinuclear complex appeared to be the same, which is surprising in relation to the difference in the charge of the complex and to the difference in the number of coordinated water molecules, one and two per Gd 3+ for the binuclear and trinuclear complex, respectively.

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Section: Synthesis Of the Ligandmentioning

confidence: 99%

Section: H Nmrdmentioning

confidence: 99%

Section: H Nmrdmentioning

confidence: 99%

Section: H Nmrdmentioning

confidence: 99%

Section: H Nmrdmentioning

confidence: 99%

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Synthesis, complexation and NMR relaxation properties of Gd3+ complexes of Mes(DO3A)3

et al. 2011

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Synthesis and Biophysical Studies of Bis‐Macrocyclic Cobalt/Copper(II) Complexes Having a Pyridine Spacer with CT DNA and 5′‐GMP

Arjmand

Aziz

2009

Chemistry & Biodiversity

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New bis-macrocyclic complexes of Co(III), 1, Ni(II), 2, and Cu(II), 3, containing pyridyl bridges between 13-membered macrocyclic subunits, have been synthesized via an in situ one-pot template condensation reaction (IOPTCR). The proposed structures of these new dinuclear complexes are consistent with the data obtained from elemental analysis, molar conductance, IR, EPR, UV/VIS, (1)H- and 13C-NMR, and ESI-MS. The complexes 2 and 3 possess square-planar geometry with four secondary N-atoms coordinated to the metal ion, while complex 1 reveals octahedral geometry in solution due to coordinated H(2)O molecules. DNA-Binding properties of the complexes 1 and 3 were investigated by absorption and emission titrations, cyclic voltammetry, and viscosity measurements. Complexes 1 and 3 are strong DNA binders with binding constants, K(b), of 1.64 x 10(5) and 2.05 x 10(5) M(-1), respectively. Hyperchromism, decrease in emission intensity of DNA-bound ethidium bromide (EB), and changes observed in the viscosity and cyclic voltammograms in the presence of added metal complexes reveals that the complexes bind to DNA predominantly by electrostatic attraction, substantiated by absorption titration with 5'-GMP.

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Lanthanide Complexes with Heteroditopic Ligands as Fluorescent Zinc Sensors

et al. 2014

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International audienceWe report the synthesis of two ligands containing a DO3A unit (H3DO3A = 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid) linked to a triazacyclononane (TACN) moiety by a 2,6-dimethylpyridine spacer designed to form stable Ln3+ complexes in solution that respond to the presence of Zn2+ ions. The Eu3+ and Gd3+ complexes have been characterized by using a combination of experimental and theoretical techniques that include absorption and emission electronic spectroscopy, NMR spectroscopy, 1H relaxometry, and DFT calculations. The Ln3+ ions are eight-coordinated by the ligand, which binds to the metal ion through the seven donor atoms of the DO3A unit and the nitrogen atom of the pyridyl linker. Luminescence lifetime measurements recorded from solutions of the Eu3+ complexes in H2O and D2O and relaxometric measurements point to the absence of inner-sphere water molecules. The addition of Zn2+ causes important changes in the absorption spectra of the complexes that evidence the formation of both 1:1 and 2:1 (Ln3+/Zn2+) complex species. However, the emission lifetimes of the Eu3+ complexes and relaxivity experience weak changes, thus indicating that Zn2+ addition does not significantly affect the number of coordinated water molecules. The Gd3+ complexes show a weak emission band at 325 nm, the intensity of which dramatically increases in the presence of Zn2+. However, the “turn-on” behaviour induced by Zn2+ is not observed for other metal cations such as Ca2+, Mg2+ or Cu2+. DFT calculations indicate that a photoinduced electron-transfer (PET) process is responsible for the quenching of the luminescence in the absence of Zn2+

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New side-bridged bismacrocycles and cross-bridged macrotricycles. Syntheses and Cu(ii) complexation study

Cited by 24 publications

References 37 publications

Synthesis, complexation and NMR relaxation properties of Gd3+ complexes of Mes(DO3A)3

Synthesis, complexation and NMR relaxation properties of Gd3+ complexes of Mes(DO3A)3

Synthesis and Biophysical Studies of Bis‐Macrocyclic Cobalt/Copper(II) Complexes Having a Pyridine Spacer with CT DNA and 5′‐GMP

Lanthanide Complexes with Heteroditopic Ligands as Fluorescent Zinc Sensors

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