| abstract |
A contrast agent for magnetic resonance imaging, the contrast agent comprising a compound of formula (Ia), (Ib), (Ic) or (Id): **(See formula)** or a pharmaceutically acceptable salt of the compound , wherein R1 is selected from the group consisting of unsubstituted alkylene, unsubstituted cycloalkylene, unsubstituted heterocycloalkylene, unsubstituted arylene, unsubstituted heteroarylene, dialkylenarene, and dialkyleneheteroarene, wherein R2 is selected from the group consisting of hydrogen, alkyl , alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, halo, cyano, nitro, hydroxy, and alkoxy, wherein n is 2 or 3, and wherein the compound optionally includes Mn-coordinated water when n is 2. |