Coupling fast water exchange to slow molecular tumbling in Gd3+ chelates: why faster is not always better.

ABSTRACT: The influence of dynamics on solution state structure is a widely overlooked consideration in chemistry. Variations in Gd(3+) chelate hydration with changing coordination geometry and dissociative water exchange kinetics substantially impact the effectiveness (or relaxivity) of monohydrated Gd(3+) chelates as T1-shortening contrast agents for MRI. Theory shows that relaxivity is highly dependent upon the Gd(3+)-water proton distance (rGdH), and yet this distance is almost never considered as a variable in assessing the relaxivity of a Gd(3+) chelate as a potential contrast agent. The consequence of this omission can be seen when considering the relaxivity of isomeric Gd(3+) chelates that exhibit different dissociative water exchange kinetics. The results described herein show that the rela

SUBMITTER: Avedano S 

PROVIDER: S-EPMC3769110 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature