Mn²⁺ Complex of a Fluorinated CDTA-Derivative: Stability, Inertness, and Paramagnetic ¹H, ¹⁷O, and ¹⁹F Relaxation Properties.

ABSTRACT: L2 is a bisamide derivative of cyclohexyl-diamine tetraacetate (CDTA) containing one trifluoromethyl-piperidine- and one dimethyl-amide. While the amide functions are stable at pH 7, at pH 4.35 hydrolysis occurs after 1 day, and it is faster for the amide involving the piperidine. pH potentiometry showed lower basicity for L2 than for CDTA, and similar stability for the two complexes (pMn  =  8.28 vs. 8.68 for MnL2 and MnCDTA, respectively). The replacement of carboxylates by amides results in two orders of magnitude higher kinetic inertness for MnL2 (t_1/2 = 1134 hours vs. 12 hours; pH 7.4). ¹⁷O NMR confirmed one inner sphere water in MnL2 and fast exchange (k_ex ²⁹⁸  =  2.8 × 10⁷ s^-1). Its proton relaxivity is remarkable for

SUBMITTER: Garda Z 

PROVIDER: S-EPMC12734688 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature