Research data for "Determination of molecular hydration in solution via changes in magnetic anisotropy"

Included here are the raw electron paramagnetic resonance data sets, the density-functional theory-computed geometries and the complete active space self-consistent field-computed electronic structures for the complexes [Er(1,4,7,10-tetraazacyclododecane-1-5-((<em>tert</em>-butyl)pyridin-2-yl)methyl-4,7,10-triacetate)] and [Er(1,4,7,10-tetraazacyclododecane-1-5-((<em>tert</em>-butyl)pyridin-2-yl)methyl-4,7,10-tri(methylphosphinate))]. These data allow us to identify the solution hydration behaviour of the two complexes to show that the first complex incorporates a water molecule in the first coordination sphere, while the second does not.