Modulation of water exchange in europium(III) DOTA-tetraamide complexes via electronic substituent effects.
The chemical exchange saturation transfer (CEST) efficiency for a series Eu3+-based tetraamide complexes bearing p-substituents on a single coordinating pendant arm is highly sensitive to water exchange rates. The CEST effect increases in the order Me < MeO < F approximately CO2tBu < CN < H. These results show that CEST contrast can be modulated by changes in electron density at a single ligating atom, and this forms the basis of creating imaging agents that respond to chemical oxidation and reduction.
Ratnakar
S James
SJ
Advanced Imaging Research Center, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390, USA.
Woods
Mark
M
Lubag
Angelo J M
AJ
Kovacs
Zoltan
Z
Sherry
A Dean
AD
D000577:Amides / Q000737:chemistry*; D003287:Contrast Media / Q000138:chemical synthesis*; D004583:Electrons; D005063:Europium / Q000737:chemistry*; D008024:Ligands; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010084:Oxidation-Reduction; D013329:Structure-Activity Relationship; D014867:Water / Q000737:chemistry*
D000577:Amides; D003287:Contrast Media; D008024:Ligands; D009942:Organometallic Compounds; D014867:Water; D005063:Europium