Di‐μ‐sulfato‐O:O'‐bis[(2‐aminopyrimidine‐N1)triaquacobalt(II)] Dihydrate (1), catena‐Poly[bis(2‐aminopyrimidine‐N1)diaquanickel(II)‐μ‐sulfato‐O:O' 2‐Aminopyrimidine] (2), (2‐Aminopyrimidine‐N1)pentaaquanickel(II) Sulfate 2‐Aminopyrimidine (3) and catena‐Poly[bis(2‐aminopyrimidine‐N1)aquacopper(ii)‐μ‐sulfato‐O:O' Dihydrate] (4)

2-Aminopyrimidine complexes of aqueous CoII, NiII and CuII sulfate have been prepared and their structures determined by X-ray diffraction. CoII forms a dimeric complex, [Co(SO4)(C4H5N3)(H2O)3]2.2H2O (1), and NiII and CuII form polymeric complexes, [NiSO4(C4H5N3)2(H2O)2].C4H5N3 (2) and [CuSO4(C4H5N3)2(H2O)].2H2O (4). The sulfato ion acts as a bridging moiety between the metal atoms in these three complexes. The NiII ion also forms an ionic complex, [Ni(C4H5N3)(H2O)5]SO4.C4H5N3 (3), in which the coordination of 2-aminopyrimidine to the metal is always through the ring N atom.