Supramolecular activation of a molecular photocatalyst

The effects of the planar aromatic organic molecules anthracene and pyrene on the catalytic performance of the intramolecular hydrogen evolving photocatalyst [Ru(tbbpy)(2)(tpphz)PdCl2](PF6)(2) functioning as a photocatalytic dyad have been studied. H-1-NMR studies on [Ru(tbbpy)(2)(tpphz)PdCl2](PF6)(2) and [Ru(tbbpy)(2)(tpphz)](PF6)(2) show a pronounced interaction of pyrene with the ruthenium complexes due to pi-pi-interactions. The solid state structure of [Ru(tbbpy)(2)(tpphz)PdCl2](2)[Mo8O24] shows a pronounced pi-pi-stacking of the polyaromatic ligands. In addition, dimerization constants for the complexes and association constants between the complexes and pyrene were determined. Studies on the photocatalytic hydrogen production show a decreased induction phase and increased turn over frequencies during the initial phase of the catalysis in the presence of anthracene and pyrene utilising the catalyst [Ru(tbbpy)(2)(tpphz)PdCl2](PF6)(2) irrespective of the nature of the polycyclic aromatic hydrocarbon.