Shining a Light on s-Triazine-Based Polymers

The strong interplay between the structure and optical properties of conjugated s-triazine-based framework (CTF) materials is explored in a combined experimental and computational study. The experimental absorption and fluorescence spectra of the CTF-1 material, a polymer obtained through the trimerization of 1,4-dicyanobenzene, are compared with the results of time-dependent density functional theory and approximate coupled cluster theory (CC2) calculations on cluster models of the polymer. To help explain the polymer data, we compare its optical properties with those measured and predicted for the 2,4,6-triphenyl-1,3,5-triazine model compound. Our analysis shows that CTFs, in line with experimental diffraction data, are likely to be layered materials based around flat hexagonal-like sheets and suggests that the long-wavelength part of the CTF-1 absorption spectrum displays a pronounced effect of stacking. Red-shifted peaks in the absorption spectrum appear that are absent for an isolated sheet. We also ...