Mixed lanthanide coordination polymers for temperature sensing and enhanced NdIII NIR luminescence

Abstract Three Ln III coordination polymers, [Ln 2 L 3 (NO 3 ) 3 ] n ·2CH 3 COOCH 2 CH 3 (Ln = Nd (Nd 2 L 3 ), Eu (Eu 2 L 3 ), Tb (Tb 2 L 3 )), following coordination-assembly reactions involving a new bi-monodentate salicylamide ligand, L = 1,4-bis[(2΄-thenylaminoformyl)phenoxyl]methyl}-benzene, have been successfully synthesized. Among them, Nd 2 L 3 and Tb 2 L 3 were structurally authenticated by single-crystal X-ray diffraction and the results indicate both Nd 2 L 3 and Tb 2 L 3 are one-dimensional corrugated blockchains with Ln III containing 64-membered block loops filled by ethyl acetate molecules alternating in nearly orthogonal directions. For they are isomorphous, two binary co-doped lanthanide coordination polymers, Tb 0.965 Eu 1.035 L 3 and Tb 0.717 Nd 1.283 L 3 are obtained. Luminescent studies indicate that Tb 0.965 Eu 1.035 L 3 exhibits a temperature recognition property with the significantly high sensitivity of 2.61% per K in the 296–386 K temperature range upon excitation at 345 nm as well as white emission when excited in the range of 370–390 nm. Tb 0 .717 Nd 1.283 L 3 shows enhanced Nd III -centred NIR luminescence and diminished Tb III -centred luminescence as compared to those of Nd 2 L 3 and Tb 2 L 3 . The results presented herein show that the energy transfer from Tb III to both Eu III and Nd III has been successfully achieved in Tb 0.965 Eu 1.035 L 3 and Tb 0.717 Nd 1.283 L 3 . Generally speaking, this work explores the potential applications of lanthanide-based coordination polymers based on multi-monodentate salicylamide ligand in the area of thermal sensing.