A new macrocyclic ligand 1,4,7,10,-tetraazacyclododecane-1,4,7,10-tetrakis(methanephosphonic acid mono(2',2',2'-trifluoroethyl) ester) (F-DOTPME) has been prepared and some of its metal binding properties examined. The ligand protonation constants (log K-1 = 10.5, log K-2 = 6.7) and its stability constant with Ca-II (log K-CaL = 8.4) were determined by pH potentiometry. The stability of the La-III complex could not be determined by potentiometry so it was evaluated in an EDTA competition experiment using P-31 NMR to nor the reaction. The dissociation kinetics of La(F-DOTPME)(-) was slow, with a k(d,obs) of only 1.0 x 10(-7) s(-1). A series of Ln(F-DOTPME)(-) complexes (Ln(III) = La, Gd, Dy, Tm, and Yb) were examined by multinuclear NMR. The spectra show that these complexes exist in aqueous solution as a mixture of stereoisomers of nearly equal energy (energy differences of less than I kJ/mol). Several resolved F-19 resonances in the NMR spectra of the Dy(F-DOTPME)(-), Tm(F-DOTPME)(-), and Yb(F-DOTPME)(-) complexes have been assigned to specific diastereomers by comparing resonance integrals, assuming an interaction model between neighboring pendant arms, and the magnitude and direction of the hyperfine F-19 NMR shifts induced by the paramagnetic lanthanide cation. Cationic detergents added to two different Ln(F-DOTPME)(-) complexes altered the distribution of isomers in favor of the symmetrical Delta-SSSS isomer, while neutral polyethylene glycol affected the F-19 chemical shifts of some isomers without altering their populations. Gd(F-DOTPME)(-) displayed a water proton relaxivity (R-I) of 2.5 mM(-1) s(-1) at 25 degrees C and 40 MHz, typical of complexes lacking an inner-sphere-coordinated water molecule. O-17 NMR was used to confirm that Dy(F-DOTPME)(-) does not have an inner-sphere-coordinated water molecule. Addition of human serum albumin to aqueous solutions of Gd(F-DOTPME)(-) produced a 4-fold increase is water relaxivity, anti an analysis of binding curves indicated the fluorinated complex binds to HSA with a binding constant of about 0.17 mM.