Resumen de Preparation and Thermochromic Properties of Copper(II)-N,N-Diethylethylenediamine Complexes

Ai-Li Cui, Xi Chen, Long Sun, Jing-Zhi Wei, Jin Yang, Hui-Zhong Kou

• The synthesis and characterization of two copper(II) complexes, [Cu(deen)2](BF4)2 and [Cu(deen)2](NO3)2 (deen = N,N-diethylethylenediamine), that show interesting thermochromic properties, are described. The subtle alternation of coordination geometry around Cu(II) is responsible for the color change from red to violet. This experiment is suitable for first-year chemistry students and could demonstrate one of the colorful properties of chelate compounds.