Pyrene-Based Approach to Tune Emission Color from Blue to Yellow

The development of functionalized, luminescent, pyrene-based monomers has been and continues to be an area of great interest in terms of the design and fabrication of optical and electronic devices. Herein, a facile strategy to tune the emission color of pyrene-based chromophores has been established by simple functional group modification at the para position to the diphenylamino on the donor building block. Intriguing photophysical properties were obtained and are described both in different solutions and in the solid state. The results obtained could be explained by the Hammett method and by density functional theory (DFT) calculations. A good correlation was observed between the Hammett σ_para constants of the functional groups para to the phenyl and the wavenumber (cm^-1) of the emission profile. This positive correlation, namely between the σ constants of the functional groups and the emission properties of the monomers, can be used to develop a predictive method for these types of systems.