scholarly journals Water exchange in lanthanide complexes for MRI applications. Lessons learned over the last 25 years

2019 ◽  
Vol 48 (30) ◽  
pp. 11161-11180 ◽  
Author(s):  
Peter Caravan ◽  
David Esteban-Gómez ◽  
Aurora Rodríguez-Rodríguez ◽  
Carlos Platas-Iglesias

Coordination chemistry offers convenient strategies to modulate the exchange of coordinated water molecules in lanthanide-based contrast agents.

Author(s):  
Chihiro Kachi-Terajima ◽  
Norihisa Kimura

The title lanthanide complexes, [Ln(DAPBH2)(CH3OH)(H2O)3]Cl3·2CH3OH [Ln III = Tb and Dy; DAPBH2 = 2,6-diacetylpyridine bis(benzoylhydrazone), C23H21N5O2], are isotypic. The central lanthanide ions are nine-coordinate, being ligated by three N and two O atoms from the pentadentate DAPBH2 ligand, and four O atoms from the coordinated methanol molecule and three coordinated water molecules. The coordination geometry of the lanthanide ion is a distorted capped square antiprism. In the crystals, the various components are linked by O—H...Cl, N—H...Cl and O—H...O hydrogen bonds, forming three-dimensional supramolecular frameworks. Within the frameworks, there are C—H...Cl and C—H...O hydrogen bonds and offset π–π interactions (intercentroid distance ca 3.81 Å).


2019 ◽  
Vol 48 (5) ◽  
pp. 1693-1699 ◽  
Author(s):  
BeiBei Zhang ◽  
Likun Cheng ◽  
Bing Duan ◽  
Weijun Tang ◽  
Yuan Yuan ◽  
...  

Diethylenetriamine-N-oxide pentaacetic acid-bisamide-based Gd(iii) complexes with 3 coordinated water molecules have been synthesized to achieve high stability and over three times of the relaxivities of commercial MRI contrast agents.


Author(s):  
S. W. Annie Bligh ◽  
Michael G. B. Drew ◽  
Noreen Martin ◽  
Beatrice Maubert ◽  
Jane Nelson

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Hsien-Ya Lin ◽  
Chia-Yu Chen ◽  
Ting-Chien Lin ◽  
Lun-Fu Yeh ◽  
Wei-Che Hsieh ◽  
...  

AbstractIrinotecan inhibits cell proliferation and thus is used for the primary treatment of colorectal cancer. Metabolism of irinotecan involves incorporation of β-glucuronic acid to facilitate excretion. During transit of the glucuronidated product through the gastrointestinal tract, an induced upregulation of gut microbial β-glucuronidase (GUS) activity may cause severe diarrhea and thus force many patients to stop treatment. We herein report the development of uronic isofagomine (UIFG) derivatives that act as general, potent inhibitors of bacterial GUSs, especially those of Escherichia coli and Clostridium perfringens. The best inhibitor, C6-nonyl UIFG, is 23,300-fold more selective for E. coli GUS than for human GUS (Ki = 0.0045 and 105 μM, respectively). Structural evidence indicated that the loss of coordinated water molecules, with the consequent increase in entropy, contributes to the high affinity and selectivity for bacterial GUSs. The inhibitors also effectively reduced irinotecan-induced diarrhea in mice without damaging intestinal epithelial cells.


1996 ◽  
Vol 2 (12) ◽  
pp. 1607-1615 ◽  
Author(s):  
Éva Tóth ◽  
Dirk Pubanz ◽  
Sylvain Vauthey ◽  
Lothar Helm ◽  
André E. Merbach

Nanoscale ◽  
2015 ◽  
Vol 7 (36) ◽  
pp. 14829-14837 ◽  
Author(s):  
Vasudevanpillai Biju ◽  
Morihiko Hamada ◽  
Kenji Ono ◽  
Sakiko Sugino ◽  
Takashi Ohnishi ◽  
...  

Multimodal and multifunctional contrast agents receive enormous attention in the biomedical imaging field.


2017 ◽  
Vol 73 (11) ◽  
pp. 1599-1602 ◽  
Author(s):  
Matimon Sangsawang ◽  
Kittipong Chainok ◽  
Nanthawat Wannarit

The title compound, [CdNa2(C8H4O4)2(C3H7NO)(H2O)2]nor [CdNa2(1,3-bdc)2(DMF)(H2O)2]n, is a new CdII–NaIheterobimetallic coordination polymer. The asymmetric unit consists of one CdIIatom, two NaIatoms, two 1,3-bdc ligands, two coordinated water molecules and one coordinated DMF molecule. The CdIIatom exhibits a seven-coordinate geometry, while the NaIatoms can be considered to be pentacoordinate. The metal ions and their symmetry-related equivalents are connectedviachelating–bridging carboxylate groups of the 1,3-bdc ligands to generate a three-dimensional framework. In the crystal, there are classical O—H...O hydrogen bonds involving the coordinated water molecules and the 1,3-bdc carboxylate groups and π–π stacking between the benzene rings of the 1,3-bdc ligands present within the frameworks.


2017 ◽  
Vol 73 (12) ◽  
pp. 1977-1980
Author(s):  
Volodymyr M. Hiiuk ◽  
Diana D. Barakhty ◽  
Sergiu Shova ◽  
Ruslan A. Polunin ◽  
Il'ya A. Gural'skiy

In the title polymeric complex, {[Fe(C12H10N2)2(H2O)4](CH3C6H4SO3)2·2CH3OH}n, the FeIIcation, located on an inversion centre, is coordinated by four water molecules in the equatorial positions and two 1,2-bis(pyridin-4-yl)ethene molecules in the axial positions. This results in a distorted octahedral geometry for the [N2O4] coordination polyhedron. The 1,2-bis(pyridin-4-yl)ethene molecules bridge the FeIIcations, forming polymeric chains running along thea-axis direction. Stabilization of the crystal structure is provided by O—H...O hydrogen bonds; these are formed by coordinated water molecules as donors towards the O atoms of the methanol molecules and tosylate anions as acceptors of protons, leading to the formation of a three-dimensional supramolecular network. Weak C—H...O hydrogen bonds are also observed in the crystal.


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