Abstract
A semi-empirical equation to estimate the hydration number of Mn(II) complexes was derived from a database of 49 previously published 1H longitudinal Nuclear Magnetic Relaxation Dispersion profiles. This equation has the longitudinal 1H relaxivity and the molecular weight of the Mn(II) complex under consideration as parameters.
Highlights
During the last decades, Gd3+ -chelates, such as Gd-DTPA (DTPA = diethylenetriamineN,N,N’,N”,N”,N”’-pentaacetate) and Gd-DOTA (DOTA = 1,4,7,10-tetraazacyclododecane-N,N’,N”,N”’tetraacetate), have become indispensable tools for the contrast enhancement of magnetic resonance images [1,2,3]
The relaxivity has an inner-sphere contribution by water molecules exchanging between the first coordination sphere of the metal ion and the bulk and an outer-sphere contribution due to water molecules in the bulk that diffuse in the surroundings of the metal ion without being bound to it (r1,OS ) (see Equation (1))
Since the electronic relaxation time (T1e ) for Mn2+ -complexes was generally larger than the rotational correlation time (τ R ), the contribution of the Curie relaxation mechanism to the longitudinal relaxation was negligible; only the dipolar and the scalar mechanisms needed to be taken into consideration
Summary
Gd3+ -chelates, such as Gd-DTPA (DTPA = diethylenetriamineN,N,N’,N”,N”,N”’-pentaacetate) and Gd-DOTA (DOTA = 1,4,7,10-tetraazacyclododecane-N,N’,N”,N”’tetraacetate), have become indispensable tools for the contrast enhancement of magnetic resonance images [1,2,3]. These contrast agents (CAs) have proven to be generally extremely safe; only 0.03% of all administrations (about 100 million worldwide) gave rise to serious adverse effects. During recent years, some concerns have arisen because of (i) incidents of nephrogenic systemic fibrosis (NSF). High spin d5 Mn2+ is an attractive alternative for f 7 Gd3+ , because it has only two less unpaired electrons, whereas a high electronic symmetry is favorable for high relaxivities
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
