Construction of Highly Luminescent Lanthanide Coordination Polymers and Their Visualization for Luminescence Sensing.

NaH 2 SIP was selected as an organic ligand (NaH 2 SIP = 5-sulfoisophthalic acid monosodium salt). We successfully constructed a new class of lanthanide coordination polymers Ln-HS ([Ln(SIP)(DMF)(H 2 O) 4 ]DMF·H 2 O; Ln = Eu, Tb, Sm, and Dy) by a simple solvothermal synthesis method. They exhibited excellent photoluminescence properties for Ln 3+ ions, where Eu-HS and Tb-HS exhibited high quantum yields of 13.70 and 42.38%, respectively. The codoped lanthanide coordination polymers obtained by doping with different ratios of Eu 3+ /Tb 3+ serve as excellent ratiometric thermometers with high sensitivities in the physiological temperature range, with values of 16.8, 7.0, and 14.5%·K -1 , respectively. The luminescent colors of Tb 0.95 Eu 0.05 -HS and Tb 0.94 Eu 0.06 -HS exhibit variations from green to yellow to orange, achieving visualized luminescence in a narrow temperature range. The composite film material Tb 0.94 Eu 0.06 -HS@PMMA demonstrates this color variation. Next, Tb 0.5 Sm 0.5 -HS obtained by Tb 3+ /Sm 3+ codoping was investigated. The difference in the luminescence colors visible to the naked eye at different excitation wavelengths and the change in luminescence colors occur in a very narrow temperature range. All of them show the great value of the visualized luminescence in practical anticounterfeiting, with double anticounterfeiting function and high security.