Ratiometric Thermometer Based on a Lanthanoid Coordination Polymer

The new luminescent lanthanum‐based coordination polymer LaHL, ({[La(HL)(H2O)2]·H2O}n, H4L = 5‐hydroxy‐1,2,4‐benzenetricarboxylic acid) has been synthesized by hydrothermal methods. By the addition of 5 % of a Tb or Eu salt to the reaction mixture, the doped compounds La0.95Tb0.05HL and La0.95Eu0.05HL were obtained, with the same structure as LaHL. The compound La0.95Tb0.05HL can be used as a ratiometric thermometer over the temperature range 90–280 K with a sensitivity of up to 0.53 % K–1 at 280 K.