Molecular packing and aggregation-induced emission of 4-dicyanomethylene-2,6-distyryl-4H-pyran derivatives

Absorption and photoluminescence (PL) spectra of two derivatives of 4-dicyanomethylene-2,6-distyryl-4H-pyran were studied both in solution and in aggregation states. Although structurally similar, they show completely different emission behavior and an unusual aggregation-induced emission (AIE). Different molecular structure and packing are proposed as the major reason for these intriguing phenomena. (c) 2006 Elsevier B.V. All rights reserved.