Synthesis and Characterization of Hexanuclear Rhenium Chalcogenide Clusters Containing Potential Two-Photon Absorbing Ligands and the Synthesis and Characterization of Gold-Substituted Coumarins

Hexanuclear rhenium clusters of the form Re₆(μ³-Q₈)(PR₃)₄X₂, (Q = Se, S and X = Br- or I-), and Re₆(μ³-Q₈)(PR₃)₄(PEt₃)₂, where PR₃ = tris(4-(4-tert-butylstyrenyl)phenyl)phosphine (PTbs₃) have been synthesized and characterized. PTbs₃ was chosen for its potential as a two-photon absorbing ligand. Binding of PTbs₃ to the cluster core does not completely quench the luminescence of the cluster core. The requirements for Förster energy transfer (FRET) have also been fulfilled. Accessing to the triplet state emission of the cluster core by exciting the PTbs₃ ligand using lower-energy light should be achieved.

Coumarins substituted at the 6-, 7-, and 8-positions with (phosphine/carbene)gold(I) fragments have also been synthesized in an effort to probe the luminescent properties brought about by a heavy atom such as gold. Each new substituted-coumarin has been characterized by multi-nuclear NMR, elemental combustion analysis, UV-Vis spectroscopy and emissions spectroscopy. In each case, the addition of the gold(I) fragment resulted in the observance of triplet-state emission at room temperature which was not observed for the free coumarin molecule.