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.