Luminescent Cu4I4-cubane clusters based on N-methyl-5,10-dihydrophenarsazines

Two luminescent Cu4I4-cubane tetramers with N-methyl-10-(p-halogenophenyl)-5,10-dihydrophenarsazine ligands were synthesized and characterized by NMR spectroscopy, mass spectrometry, elemental analysis, and single-crystal X-ray diffraction analysis. The UV-Vis absorption and emission properties were studied and rationalized by DFT and time-dependent DFT calculations. The luminescence behavior was found to be rather different from that of recently reported tetranuclear copper iodide cubane clusters based on As,O-analogues - 10-(aryl)phenoxarsines. The crystalline powders of both complexes exhibit the temperature-dependent dual-band emission: the low-energy emission originates from the cluster-centered ((CC)-C-3) triplet state, whereas the high-energy emission was attributed to the intraligand ((IL)-I-3) triplet state.

Automated summary

Two luminescent Cu4I4-cubane tetramers with N-methyl-10-(p-halogenophenyl)-5,10-dihydrophenarsazine ligands were synthesized and characterized. Their UV-Vis absorption and emission properties were studied and rationalized by DFT calculations. The crystalline powders of both complexes exhibit temperature-dependent dual-band emission.