Metal-organic frameworks of lanthanide iminodiacetates and tartrates:Synthesis,structural characterization and luminescence properties——Commemorating the 100th anniversary of the birth of Academician Guangxian Xu

Two series of lanthanide-containing metal-organic frameworks(Ln-MOFs)of the general formula{[Ln(HIDA)_(2)H_(2)O]ClO_(4)·H_(2)O}_n(Ln=La(1),Nd(2),Eu(3),Gd(4),Tb(5),Eu:Tb(6);H_(2)IDA=iminodiacetic acid)and[Ln(TT)(HTT)(H_(2)O)_3]_n(Ln=Eu(7),Gd(8),Tb(9),Dy(10),and Eu:Tb(11);H_(2)TT=tartaric acid)were synthesized by reacting Ln(ClO_(4))_3 with iminodiacetic acid and L-tartaric acid,respectively.All compounds were structurally characterized by single-crystal X-ray diffraction.Elemental analyses are co nsistent with the corre sponding crystallographically generated formulas.Mo reover,the luminescence properties of both the single and mixed-lanthanide complexes were studied.Near infrared,red,and green emissions that are characteristic of Nd(Ⅲ),Eu(Ⅲ),and Tb(Ⅲ)are observed for 2,3/7,and 5/9,respectively.For the two mixed-lanthanide complex systems 6 and 11,depending on the relative amount of Eu(Ⅲ)and Tb(Ⅲ),the color of emission can be fine-tuned.It is found that a small amount of Eu(Ⅲ)is adequate for the observation of the most intense transition of Eu(Ⅲ).This is believed to be a result of energy transfer from Tb(Ⅲ)to Eu(Ⅲ)within the same complex-a conclusion supported by the significantly shortened lifetime of Tb(Ⅲ)and the accompanying enhanced lifetime of Eu(Ⅲ)in the mixedlanthanide complex with respect to the corresponding values for the pure Tb(Ⅲ)and Eu(Ⅲ)complexes with the same ligand.