The crystallized solvent could influence the lanthanide water bonding?

Two gadonilium DOTAM complexes [Gd(DOTAM)H2O](CF3SO3)3 · 3H2O (1) and [Gd(DOTAM)H2O](CF3SO3)3 · 0.5H2O · 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–Owater bond lengths of 2.396(6) and 2.474(7) Å in (2) where two independent molecules are present in the crystal cell. The factors influencing the Gd–Owater 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 · H2O · CH3CN (3) reveals an unexpected twisted square antiprismatic (TSA) coordination geometry characteristic of the m isomer.