Synthesis, structure and photophysical properties of a 2D network with gold dicyanide donors coordinated to azahelicene viologen acceptors†
A recently synthesized photoluminescent organic acceptor, 5,10-dimethyl-5,10-diazahelicene is shown to react with dicyanoaurate anions to form a 2D network N,N-dimethylazahelicene dicyanoaurate. The structure of the synthesized complex was investigated via X-ray crystallography showing the presence of [Au(CN)2]− dimers and monomers within the helicene framework. Photophysical measurements between 298 K and 10 K indicate quenching of the [Au(CN)2]− anion by 5,10-dimethyl-5,10-diazahelicene via an electron transfer. A Stern–Volmer and Rehm–Weller analysis shows that this is a result of quenching from transfer of an electron from [Au(CN)2]− anions to 5,10-dimethyl-5,10-diazahelicene as opposed to resonance energy transfer. DFT calculations were performed to support the assignment of an electron transfer.