Two Chiral Metal Clusters Derived from Nucleophilic Addition of l-proline to Di-2-pyridyl Ketone

In the presence of cobalt (nickel) acetate, a chiral tetrahedral intermediate ligand of (S)-(C5NH4)2C(OH)(C4NH7CO2H) was first formed from the nucleophilic addition of l-proline as a secondary amine to ketone (di-2-pyridyl ketone). Based on the ligand synthesized in situ, two chiral tetranuclear isomorphous complexes 1 and 2 with the formula {Na[M4L3(OAc)3](ClO4)1.5(H2O)1.5}(ClO4)(OH)0.5·3H2O (M = Co, Ni) have been achieved. The Co4 cluster (1) behaves as a ferromagnet.