Cu4I4-cubane clusters based on 10-(aryl)phenoxarsines and their luminescence

In this work, we present the synthesis, structural and photophysical characterization, and theoretical study of tetranuclear copper(I) cubane-type Cu4I4 clusters 6–10 with different 10-(aryl)phenoxarsine ligands – 10-(p-fluorophenyl)phenoxarsine (1), 10-(p-ethoxyphenyl)phenoxarsine (2), 10-(phenyl)phenoxarsine (3), 10-(m-fluorophenyl)phenoxarsine (4), and 10-(o-methoxyphenyl)phenoxarsine (5), respectively. The structures of 1–5 were confirmed by NMR spectroscopy, mass spectrometry, elemental analysis and for complexes 6, 7, and 10 by single-crystal X-ray diffraction analysis. The UV/Vis absorption and emission properties were studied and rationalized by DFT and time-dependent DFT calculations. In the solid state, under UV irradiation, all complexes exhibit an intense green emission, which was attributed to a cluster-centered triplet state.