Polynuclear cage-like Au(i) phosphane complexes based on a S2− template: observation of multiple luminescence in coordinated polyaromatic systems†
A rational approach to the synthesis of cage-like compounds has been realized to build a new family of sulfido-phosphane Au(I) polynuclear complexes. Ditopic phosphane ligands with an extended aromatic system were used to obtain cage compounds with a clearly determined geometry. Au(I) complexes have been fully characterised in solution using spectroscopy methods, and DFT optimisation of the molecular structure gives additional arguments in favour of the suggested structural patterns. All complexes obtained are luminescent in solution and in the solid state, and display multiple emissions with an unusual combination of two phosphorescence bands and one fluorescence band. DFT calculations show that multiple emissions were mainly determined by 1IL and metal perturbed 3IL transitions. The ratio of singlet and triplet emission components depends on the distance between the ligand chromophoric centre and Au(I).