The two Zn^II atoms in the crystal structure of the title complex, [Zn(NO₃)₂(C₁₀H₂₄N₄)]·CH₃OH, have a distorted octahedral coordination sphere, defined by 1,4,8,11-tetraazacyclotetradecane (cyclam) N atoms in the equatorial plane and nitrate O atoms in the axial sites. The conformation of the cyclam is trans-III (R, R, S, S), which is typical for metal–cyclam complexes. Nitrate anions are involved in intra- and intermolecular hydrogen bonding with the N–H groups of the Zn^II–cyclam unit. Together with the methanol solvent molecule, the hydrogen-bonding network connects the Zn^II–cyclam units into ribbons running parallel to the a axis.

In the structure of the title complex, [Zn(C₄H₂FN₂O₂)(C₁₀H₂₄N₄)]ClO₄, the zinc(II) ion forms coordination bonds with the four nitrogen atoms of cyclam (1,4,8,11-tetraazacyclotetradecane or [14]aneN4) as well as with the nitrogen atom of a deprotonated 5-fluorouracil ion (FU⁻). Cyclam adopts a trans-I type conformation within this structure. The coordination structure of the zinc(II) ion is a square pyramid with a distorted base plane formed by the four nitrogen atoms of the cyclam. FU⁻ engages in intermolecular hydrogen bonding with neighboring FU⁻ molecules and with the cyclam molecule.