The crystallized solvent could influence the lanthanide water bonding?

Two gadonilium DOTAM complexes [Gd(DOTAM)H2O](CF3SO3)(3) center dot 3H(2)O (1) and [Gd(DOTAM)H2O](CF3SO3)(3) center dot 0.5H(2)O center dot CH3CN (2) have the structure of the M isomer, with coordination geometry around the Gd ion capped square antiprismatic (SA). They differ for the Gd-O-water bond lengths of 2.396(6) and 2.474(7) angstrom in (2) where two independent molecules are present in the crystal cell. The factors influencing the Gd-O-water bond distance, important for the water exchange rate in MRI experiments, have been correlated to the different network of hydrogen bonds involving the Gd coordinated water molecule. The X-ray structure of the parent compound [Pr(DOTAM)H2O](CF3SO3)(3) center dot HO center dot CH3CN (3) reveals an unexpected twisted square antiprismatic (TSA) coordination geometry characteristic of the In isomer.