Highly soluble tris-hydroxypyridonate Gd(III) complexes with increased hydration number, fast water exchange, slow electronic relaxation, and high relaxivity.
The design, synthesis, and relaxivity properties of highly soluble TACN-capped trishydroxypyridonate-Gd(III) complexes are presented. Molecular mechanics modeling was used to help design a complex capable of possessing three water molecules in the inner metal coordination sphere, an attractive property for high-relaxivity MRI contrast agents. The measured relaxivities of 13.1 and 12.5 mM-1 s-1 (20 MHz, 298 K) for two TACN-capped complexes are among the highest known relaxivities of low-molecular weight Gd complexes and are consistent with three coordinated waters, an extremely fast water exchange rate, and long electronic relaxation time. Luminescence measurements to confirm the number of coordinated water molecules for the first time in the HOPO series are also discussed.
Werner
Eric J
EJ
College of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Avedano
Stefano
S
Botta
Mauro
M
Hay
Benjamin P
BP
Moore
Evan G
EG
Aime
Silvio
S
Raymond
Kenneth N
KN
D001372:Aza Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D003287:Contrast Media / Q000138:chemical synthesis / Q000737:chemistry*; D005682:Gadolinium / Q000737:chemistry*; D007700:Kinetics; D008279:Magnetic Resonance Imaging / Q000379:methods; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010880:Piperidines / Q000138:chemical synthesis / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry; D012995:Solubility; D014867:Water / Q000737:chemistry
D001372:Aza Compounds; D003287:Contrast Media; D009942:Organometallic Compounds; D010880:Piperidines; D011725:Pyridines; C014047:hydroxypyridines; C482777:triazacyclononane; D014867:Water; D005682:Gadolinium