Revisiting acene dimers: A comprehensive theoretical study of a less explored conformer

Dimers of the acenes naphthalene, anthracene, tetracene, and pentacene are shown to have a C2 symmetric X-shaped lowest minimum structure, while slipped-stacked and cross-shaped minima have higher energies. This is shown at the B3LYP-D3(BJ)/def2-TZVP level of theory and validated with the PNO-LCCSD(T)-F12 method. A SAPT analysis provides insight into the nature of the interaction. Finally, we performed experimental UV–Vis spectroscopy and fluorescence studies to shed light on assembling in solution. The comparison of computed UV-spectra of different dimers with experimental results helps in understanding the association process.