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Two type lanthanide complexes obtained by salen-type ligand N,N'-ethylenebis(salicylideneimine) (HL) and N,N'-ethylene-bis(3-methoxysalicylideneimine) (HL) have been isolated. They are 2D coordination polymer [Yb(HL)(NO)] ( 1), mononuclear Ln(HL)(NO) [Ln = Sm ( 2), Ho ( 3)]. The structures of 1- 3 were determined by single crystal X-ray crystallographic studies and their photophysical properties were investigated. [ABSTRACT FROM AUTHOR]

The luminescence properties of the tetranuclear bimetallic lanthanide complexes Sm2Eu2 ( 1) and Eu2Tb2 ( 2), were compared with those of the analogous homometallic complexes [Sm4(μ3-OH)2(salen)2(acac)6(CH3OH)2] ·CH3OH ( 3) and [Eu4(μ3-OH)2(salen)2(acac)6(CH3OH)2] ( 4) [H2salen = N, N′-ethylenebis(salicylideneimine), Hacac = acetylacetonate]. X-ray crystallographic analysis reveals that complexes 3 and 4 have planar tetranuclear structures. For the Eu2Tb2 configurational isomer, the TbIII ion in complex 2 mainly serves as a sensitizer. The quantum yields and lifetime measurements for 2 support the premise that Ln/ Ln energy transfer occurs in such lanthanide bimetallic complexes, along with the usual ligand-to-metal triplet energy pathways. Complexes 3 and 4 exhibit the characteristic metal-centered emission. [ABSTRACT FROM AUTHOR]