Photoactive building blocks for coordination complexes: Gilding 2,2′:6′,2″-terpyridine

The alkyne unit of 4`-ethynyl-2,2`:6`,2 ``-terpyridine has been functionalized with Ph(3)PAu, (2-tolyl)(3)PAu or Au(dppe)Au units to produce compounds 1-3, respectively. These derivatives have been characterized by electrospray mass spectrometry, solution (1)H and (13)C NMR, UV-Vis and emission spectroscopies, and single crystal X-ray diffraction. In the solid state, molecules of 1 or 2 pack with separated domains of tpy and R(3)PAu units; the tpy units in 2 (but not 1) exhibit face-to-face pi-stacking. Compound 3 crystallizes as 2(3)-CHCl(3), and the folded conformation of the dppe backbone results in a short (2.9470(8) angstrom) aurophilic interaction. Folded molecule 3 captures CHCl(3), preventing intramolecular face-to-face pi-interactions between the tpy units. In CH(2)Cl(2) solution, 1-3 are emissive when excited between 230 and 300 nm, but over minutes when lambda(ex) = 230 nm, the emission bands decay as the compounds photodegrade.