Thermally Stable Zinc Disalphen Macrocycles Showing Solid-State and Aggregation-Induced Enhanced Emission

In order to investigate the solid-state light emission of zinc salphen macrocycle complexes, 7 dinuclear zinc salphen macrocycle complexes (1-7), with acetate or hexanoate coligands, are synthesized. The complexes are stable in air up to 300 degrees C, as shown via thermogravimetric analysis (TGA), and exhibit green to orange-red emission in solution (lambda(em) = 550-600 nm, PLQE <= 1%) and slightly enhanced yellow to orange-red emission in the solid state (lambda(em) = 570-625 nm, PLQE = 1-5%). Complexes 1, 2, 4, 5, and 7 also display aggregation-induced: enhanced emission (AIEE) When hexane (a nonsolvent) is added to a chloroform solution of the complexes, with complex 4 displaying a 75-fold increase in peak emission intensity upon aggregation (in 0.25:0:75 chloroform:hexane mixture).