Water soluble catalysts for NMR/MRI enhancement

A compound of formula (I),

• wherein
• R1 and R2 are each independently selected from aryl, heteroaryl, arylalkyl, and heteroarylalkyl, wherein said aryl, heteroaryl, arylalkyl, and heteroarylalkyl are each independently unsubstituted or substituted with one or more suitable substituents;
• R3 and R4 are each independently selected from hydrogen and alkyl;
• R5 is halogen or pyridinyl, wherein said pyridinyl is unsubstituted or substituted with one or more suitable substituents;
• R6 is a suitable substituent;
• and
• m is 0, 1, 2, 3, 4, 5, 6, 7, or 8;
• provided that the compound of formula (I) has at least one water-solubilizing substituent group selected from the group consisting of a polyethylene glycol-containing substituent group having a plurality of repeated —CH2CH2O— subunits, a hydroxyl group, and a carboxylic acid group, or a continuation thereof;
• wherein each suitable substituent is independently selected from the group consisting of the at least one water-solubilizing substituent group, perfluoroalkyl, perfluoroalkoxy, alkyl, alkonyl, alkynyl, hydroxyl, halo, oxo, morcapto, alkylthio, alkoxy,, nitro, azidoalkyl, aryl heteroaryl, aryloxy, heteroaryloxy, aralkyl, heteroaralkyl, aralkoxy, heteroaralkoxy, HO—(C═O)—, heterocylic, cycloalkyl, amino, alkylamino, dialkylamino, carbamoyl, alkylcarbonyl, alkylcarbonyloxy, alkoxycarbonyl, alkylaminocarbonyl, dialkylamino carbonyl, arylcarbonyl, aryloxcarbonyl, alkylsulfonyl, and arylsulfonyl.