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• W3203165013 abstract "Investigating the relaxation of water 1H nuclei induced by paramagnetic Mn(II) complexes is important to understand the mechanisms that control the efficiency of contrast agents used in diagnostic magnetic resonance imaging (MRI). Herein, a series of potentially hexadentate triazacyclononane (TACN) derivatives containing different pendant arms were designed to explore the relaxation of the electron spin in the corresponding Mn(II) complexes by using a combination of 1H NMR relaxometry and theoretical calculations. These ligands include 1,4,7-triazacyclononane-1,4,7-triacetic acid (H3NOTA) and three derivatives in which an acetate group is replaced by sulfonamide (H3NO2ASAm), amide (H2NO2AM), or pyridyl (H2NO2APy) pendants. The analogue of H3NOTA containing three propionate pendant arms (H3NOTPrA) was also investigated. The X-ray structure of the derivative containing two acetate groups and a sulfonamide pendant arm [Mn(NO2ASAm)]- evidenced six-coordination of the ligand to the metal ion, with the coordination polyhedron being close to a trigonal prism. The relaxivities of all complexes at 20 MHz and 25 °C (1.1-1.3 mM-1 s-1) are typical of systems that lack water molecules coordinated to the metal ion. The nuclear magnetic relaxation profiles evidence significant differences in the relaxivities of the complexes at low fields (<1 MHz), which are associated with different spin relaxation rates. The zero field splitting (ZFS) parameters calculated by using DFT and CASSCF methods show that electronic relaxation is relatively insensitive to the nature of the donor atoms. However, the twist angle of the two tripodal faces that delineate the coordination polyhedron, defined by the N atoms of the TACN unit (lower face) and the donor atoms of the pendant arms (upper face), has an important effect in the ZFS parameters. A twist angle close to the ideal value for an octahedral coordination (60°), such as that in [Mn(NOTPrA)]-, leads to a small ZFS energy, whereas this value increases as the coordination polyhedron approaches to a trigonal prism." @default.
• W3203165013 created "2021-10-11" @default.
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• W3203165013 date "2021-10-07" @default.
• W3203165013 modified "2023-10-14" @default.
• W3203165013 title "Understanding the Effect of the Electron Spin Relaxation on the Relaxivities of Mn(II) Complexes with Triazacyclononane Derivatives" @default.
• W3203165013 cites W152371884 @default.
• W3203165013 cites W1591463143 @default.
• W3203165013 cites W1855872228 @default.
• W3203165013 cites W1965366745 @default.
• W3203165013 cites W1966591212 @default.
• W3203165013 cites W1969043349 @default.
• W3203165013 cites W1970909057 @default.
• W3203165013 cites W1970926733 @default.
• W3203165013 cites W1971593474 @default.
• W3203165013 cites W1977740527 @default.
• W3203165013 cites W1978294300 @default.
• W3203165013 cites W1978567151 @default.
• W3203165013 cites W1979927327 @default.
• W3203165013 cites W1981949739 @default.
• W3203165013 cites W1983455466 @default.
• W3203165013 cites W1988091937 @default.
• W3203165013 cites W1990823838 @default.
• W3203165013 cites W1995609027 @default.
• W3203165013 cites W1995793167 @default.
• W3203165013 cites W1995809573 @default.
• W3203165013 cites W1995976462 @default.
• W3203165013 cites W1997151511 @default.
• W3203165013 cites W1997529464 @default.
• W3203165013 cites W1997630751 @default.
• W3203165013 cites W2002535533 @default.
• W3203165013 cites W2005056527 @default.
• W3203165013 cites W2007886414 @default.
• W3203165013 cites W2007959364 @default.
• W3203165013 cites W2008846239 @default.
• W3203165013 cites W2011215428 @default.
• W3203165013 cites W2011853401 @default.
• W3203165013 cites W2014375168 @default.
• W3203165013 cites W2015775406 @default.
• W3203165013 cites W2018951964 @default.
• W3203165013 cites W2019305811 @default.
• W3203165013 cites W2024349911 @default.
• W3203165013 cites W2032719166 @default.
• W3203165013 cites W2035524563 @default.
• W3203165013 cites W2035780524 @default.
• W3203165013 cites W2036845081 @default.
• W3203165013 cites W2037097982 @default.
• W3203165013 cites W2039293281 @default.
• W3203165013 cites W2039823535 @default.
• W3203165013 cites W2042129035 @default.
• W3203165013 cites W2049658537 @default.
• W3203165013 cites W2051471260 @default.
• W3203165013 cites W2051891162 @default.
• W3203165013 cites W2053337631 @default.
• W3203165013 cites W2058013738 @default.
• W3203165013 cites W2059812902 @default.
• W3203165013 cites W2062446285 @default.
• W3203165013 cites W2062804521 @default.
• W3203165013 cites W2067718414 @default.
• W3203165013 cites W2068906972 @default.
• W3203165013 cites W2069544319 @default.
• W3203165013 cites W2071064081 @default.
• W3203165013 cites W2071304044 @default.
• W3203165013 cites W2071357799 @default.
• W3203165013 cites W2077739389 @default.
• W3203165013 cites W2078131849 @default.
• W3203165013 cites W2078374889 @default.
• W3203165013 cites W2083228438 @default.
• W3203165013 cites W2083354755 @default.
• W3203165013 cites W2084542938 @default.
• W3203165013 cites W2089166276 @default.
• W3203165013 cites W2108299733 @default.
• W3203165013 cites W2108426110 @default.
• W3203165013 cites W2119670865 @default.
• W3203165013 cites W2128806311 @default.
• W3203165013 cites W2131350133 @default.
• W3203165013 cites W2132454074 @default.
• W3203165013 cites W2133938848 @default.
• W3203165013 cites W2142406992 @default.
• W3203165013 cites W2233686227 @default.
• W3203165013 cites W2235622330 @default.
• W3203165013 cites W2247895134 @default.
• W3203165013 cites W2326577032 @default.
• W3203165013 cites W2330939684 @default.
• W3203165013 cites W2411537103 @default.
• W3203165013 cites W2466015345 @default.
• W3203165013 cites W2478251420 @default.
• W3203165013 cites W2498388419 @default.
• W3203165013 cites W2504172113 @default.
• W3203165013 cites W2516908424 @default.
• W3203165013 cites W2553762817 @default.

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