Synthesis, Structure, and Stereochemistry of Trinuclear Metal Complexes Formed from the Phosphorus-Based Achiral Tripodal Ligand P(S)[N(Me)N=CHC6H4-o-OH]3 (LH3): Luminescent Properties of L2Cd32H2O

Neutral trinuclear metal complexes L2Cd3â2H2O, L2Mn3âMeOH, and L2Zn3âMeOH were isolated in the reaction between the phosphorus-centered achiral tris(hydrazone) P(S)[N(Me)NdCHC6H4-o-OH]3 (LH3) and the corresponding divalent metal ions. The trinuclear complexes contain two equivalent terminal metal ions (Mt) and a central metal ion (Mc). The ligand encapsulates Mt in a facial N3O3 coordination environment. From the coordination sphere of the two terminal metal ions a pair of phenolic oxygen atoms further coordinate to the central metal ion. The coordination requirements of Mc are completed by the solvents of coordination. The achiral trianionic tripodal ligand (L)3- induces chirality in the metal complexes. This results in a ¢ (clockwise) or ¤ (anticlockwise) configuration for the terminal metal ions. The enantiomeric complexes 2-4 (¢-¢ or ¤-¤) crystallize as racemic compounds. The supramolecular structures of 2-4 reveal chiral recognition in the solid-state; every molecule with the ¢-¢ configuration interacts stereospecifically, through C-HâââSdP bonds, with two ¤-¤ molecules to generate a one-dimensional polymeric chain. Photophysical studies of the diamagnetic trinuclear complexes reveal that the tricadmium complex is luminescent in the solid state as well as in solution. In contrast LH3 and L2Zn3âMeOH are nonluminescent.