Synthesis, Characterization, and Properties of Phthalimide-Fused Phenanthrenone.

The synthesis, characterization, and properties of phthalimide-fused phenanthrenone (PIP) and its dicyano derivative (PIPCN) are reported in this study. A three-step synthetic route was established for the preparation of PIP. Single-crystal X-ray diffraction revealed PIP's rigid π-conjugated framework and significant intermolecular interactions. Systematic UV-vis absorption spectra and DFT calculations demonstrated that the dicyano group in PIPCN enhances intramolecular charge transfer effects, resulting in lower LUMO energy levels compared to classical imide units such as naphthalene diimide (NDI) and perylene diimide (PDI). Furthermore, Z-scan experiments highlighted PIPCN's pronounced third-order nonlinear optical properties. These findings demonstrate that PIP and PIPCN are promising candidates for applications in organic electronics and nonlinear optical materials.