Thermochromic luminescence of a π-conjugated polymer based on boron pyridylenolate complex.

Organic materials with luminochromic properties exhibit changes in their luminescent characteristics in response to alterations in environmental factors and have attracted attention as a platform because of their applicability in luminescent sensors. A series of boron pyridylenolate complexes is a promising candidate for luminochromic dyes. It has been reported that some π-conjugated polymers composed of the boron pyridylenolate complexes exhibited luminochromic behaviors induced by mechanical forces or temperature changes. However, the generality of the mechanisms and structure-property relationships of those chromic behaviors has still been veiled. Herein, we report the solution-state thermochromic luminescence of the boron pyridylenolate polymer and the effects of the steric structure on the boron atom. The mechanistic study clarified that the solution-state luminochromic properties should be derived from the changes in intermolecular interactions. In addition, we demonstrate that the combined use of this polymer and a hyperspectral camera enables the visualization of temperature distributions within fluid samples.