Luminescent rhenium(I)–gold(I) hetero organometallics linked by ethynylphenanthrolines

The first luminescent rhenium(I)–gold(I) hetero organometallics, Re{phensingle bondtriple bond; length of mdashsingle bondAu(PPh3)}(CO)3Cl (3) and Re{(PPh3)Ausingle bondtriple bond; length of mdashsingle bondphensingle bondtriple bond; length of mdashsingle bondAu(PPh3)}(CO)3Cl (4), have been prepared using the gold(I) complex AuCl(PPh3) (PPh3 = triphenylphosphine) and the novel rhenium(I) complexes Re(phensingle bondtriple bond; length of mdashsingle bondH)(CO)3Cl (5) (phensingle bondtriple bond; length of mdashsingle bondH = 3-ethynyl-1,10-phenanthroline) or Re(Hsingle bondtriple bond; length of mdashsingle bondphensingle bondtriple bond; length of mdashsingle bondH)(CO)3Cl (6) (Hsingle bondtriple bond; length of mdashsingle bondphensingle bondtriple bond; length of mdashsingle bondH = 3,8-bis(ethynyl)-1,10-phenanthroline). All the present rhenium(I) complexes 3–6 were revealed to possess a facial configuration (fac-isomer) with respect to the three carbonyl ligands. The main frameworks for these new gold(I) organometallics were constructed by the Au–C σ-bonding (with the η1-type coordination) between the ethynylphenanthrolines and the Au(I) phosphine unit. Re(I)–Au(I) heterometallics 3 and 4 have shown single phosphorescence from the 3MLCT excited state and this observation can be interpreted in terms of the efficient intramolecular energy transfer from the Au(I) unit to the Re(I) unit.