Unsymmetrical exo-dentate IN− ligand for further self-assembly with the Zn–Nd Salen-type Schiff-base ligands

With the hetero-binuclear Zn–Nd complex from the ethylene- or phenylene-linkered Salen-type Schiff-base ligand as the building block, further self-assembly of the unsymmetrical exo-dentate IN− (IN− = isonicotinic) anion gave a 2D layer polymeric [ZnL1Nd(IN)(NO3)2]n (1) (H2L1 = N,N′-bis(3-methoxy-salicylidene)ethylene-1,2-diamine) or a discrete binuclear [ZnL2Nd(IN)(NO3)2(DMF] (2) (H2L2 = N,N′-bis(3-methoxy-salicylidene)phenylene-1,2-diamine) complex, respectively. The change of linker flexibility of two Salen-type Schiff-base ligands (H2L1 and H2L2) resulted in the difference of structures and NIR luminescent properties of their mixed-ligands complexes.