π‐Expanded Fluoranthenes as Chromophores With Tailored Properties

ABSTRACT A series of π‐expanded fluoranthene scaffolds, selectively decorated with electron donors and acceptors, were synthesized through copper‐catalyzed reactions using the corresponding nucleophiles and brominated precursors. X‐ray crystallography revealed that substitution and degree of cyclization significantly impact the overall molecular geometry and solid‐state packing of the compounds. UV/Vis absorption and emission spectroscopy, as well as electrochemistry, provided insights into the impact of substitution on the optoelectronic and redox properties. The substitution generally leads to bathochromically shifted absorption and emission bands covering the entire visible region of the electromagnetic spectrum. Under electrochemical conditions, the compounds undergo reversible oxidations and reductions, with the potentials being highly sensitive to substitution. The experimental data were corroborated by density functional theory (DFT) calculations indicating effective modulation of the frontier molecular orbital levels upon functionalization.