Threshold collision-induced dissociation of M+(pyrimidine) with xenon is studied using guided ion beam tandem mass spectrometry. M+ includes the following metal ions: Mg+, Al+, Sc+, Ti+, V+, Cr+, Mn+, Fe+, Co+, Ni+, Cu+, and Zn+. In all cases, the primary product corresponds to endothermic loss of the intact pyrimidine molecule, with minor production of MXe+ formed by ligand exchange. Additional minor reaction pathways, the result of a M+(Ar)(2) isobaric contaminant, are observed in several systems (Fe+, Co+, and Ni+). The cross-section thresholds are interpreted to yield 0 and 298 K bond dissociation energies for M+-pyrimidine after accounting for the effects of multiple ion-molecule collisions, internal energy of the reactant ions, and dissociation lifetimes. Density functional calculations at the B3LYP/6-31G* level of theory are used to determine the structures of these complexes and provide molecular constants necessary for the thermodynamic analysis of the experimental data. Theoretical bond dissociation energies are determined from single point calculations at the B3LYP/6-311+G(2d,2p) level using the B3LY-P/6-31G* optimized geometries. Excellent agreement between theory and experiment is found for the Mg+, Al+, Sc+, Mn+, Fe+(D-6), Co+, Ni+, and Zn+, whereas the theoretical bond dissociation energies to Ti+, V+, Cr+, Fe+(F-4), and Cu+ lie outside of the experimental error bars. Trends in the binding energies of pyrimidine show behavior similar to that observed for ammonia and pyridine.