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Research has been conducted on the lanthanide complexes of the tripodal ligands. The structure and solution properties of these complexes and the relaxivity properties of the gadolinium tripodal ligand complexes have been investigated and the results are discussed.

The first variable-temperature and variable-pressure stopped-flow spectrophotometric study of the sequential threading of alpha-cyclodextrin (alpha-CD) onto the guest dye Mordant Orange 10, S, is described. The quantitative ground-state and activation enthalpy, entropy and volume change studies indicate that hydrational, van der Waals, and conformational changes in S and alpha-CD determine the equilibrium and kinetic character of the system.

(Eu(DOTAM)(H20)(super3+)) was studied to determine the mechanism of the water exchange from variable temperature and pressure (super1)H and (super17) 0 NMR data.

The influence of internal motion on the relaxation of the water protons in Ln(super 111)DOTA-like complexes is detailed. The bound water internal motion also affects macromolecular complexes, but when the final effect when combined with the local motion of the chelating group should be generally less than what is observed for the monomeric species.

Examines the influence of internal motion in the relaxation of the water protons in Ln(III)-like complexes. Determination of the quadrupolar coupling constant of the bound water oxygen; Negativity of the water proton relaxivity; Ratio of the rotational correlation times for the Ln(III).

The parameters governing the water proton relaxivity of the [Gd(EGTA-BA-(CH2)12)] n n + polymeric complex were determined through global analysis of 17O NMR, EPR and nuclear magnetic relaxation dispersion (NMRD) data [EGTA-BA2–=3,12-bis(carbamoylmethyl)-6,9-dioxa-3,12-diazatetradecanedioate(2–)]. The Lipari-Szabo approach that distinguishes the global motion of the polymer (τg) from the local motion of the Gd(III)-water vector (τl) was necessary to describe the 1H and 17O longitudinal relaxation rates; therefore for the first time it was included in the global simultaneous analysis of the EPR, 17O NMR and NMRD data. The polymer consists on average of only five monomeric units, which limits the intramolecular hydrophobic interactions operating between the (CH2)12 groups. Hence the global rotational correlation time is not very high (τg 298=3880±750 ps) compared to the corresponding DTPA-BA-based polymer (about 15 monomeric units), where τg 298=6500 ps. As a consequence, the relaxivity is limited by the rotation, which precludes the advantage obtained from the fast exchanging chelating unit ( k ex 298=2.2±0.1×106 s–1). [ABSTRACT FROM AUTHOR]