N,N′-Bis(Salicylidene)-1,2-Cyclohexanediamine Lanthanide(III) Coordination Polymers: Syntheses, Crystal Structures, and Luminescence Properties

The salen-type ligand H2L [H2L = N,N'-bis(salicylidene)-1,2-cyclohexanediamine] was utilized for the synthesis of two lanthanide(III) coordination polymers [LnH(2)L(NO3)(3)MeOH](n) [Ln = Eu (1) and Ln = Lu (2)]. The single-crystal X-ray diffraction analyses of 1 and 2 revealed that they are isomorphous and exhibit one-dimension neutral structure, in which H2L effectively functions as a bridging ligand and give rise to a chain-like polymer. The luminescent properties of polymers in solid state and in solution were investigated and 1 exhibits typical red luminescence of Eu-III ions in solid state and dichloromethane solution and 2 emits the ligand-centered blue luminescence. The energy transfer mechanisms in these luminescent lanthanide polymers were described through calculation of the lowest triplet level of ligand H2L.