An Application Exploiting Aurophilic Bonding and iClick to Produce White Light Emitting Materials

The paper focuses on exploiting aurophilic bonding to produce white light emitting materials. Inorganic Click (iClick) is employed to link two or four Au(I) metal ions through a triazolate bridge. Depending on the choice of phosphine ligand (PEt3 or PPh3), dinuclear Au-2-FO or tetranuclear Au-4-FO complexes can be controllably synthesized (FO = 2-(9,9-dioctylfluoreneyl-)). The iClick products Au-2-FO and Au-4-FO are characterized by combustion analysis and multinuclear NMR, TOCSY 1D, H-1-C-13 gHMBC, and H-1-C-13 gHSQC. In addition, the photophysical properties of Au-2-FO and Au-4-FO were examined in THE solution. Transient absorption spectroscopy was employed to elucidate the excited state features of the gold compounds. Solution processed OLEDs were fabricated and characterized, which gave white light electroluminescence with CIE coordinates (0.34, 0.36), as seen referenced to CIE standard illuminant D65 (0.31, 0.32). TDDFT computational analysis of Au-2-FO and Au-4-FO reveals the origin of light emission. In the case of Au-4-FO, direct excitation leads to increased aurophilic bonding in the excited state, and as a result the emission profile is broadened to cover a larger region of the visible spectrum, thus giving white light emission. Designing molecules that can access or increase aurophilic bonding in the excited state provides another tool for fine-tuning the emission profiles of gold complexes.