Elimination of the chloride ion from the [(PPh3)AuCl] complex using silver triflate (AgOTf) in the presence of 2,2′-bipyridine R2bpy (the Au : R2bpy molar ratio is 2 : 1) in dichloromethane at room temperature leads to dinuclear gold(i) complexes [(PPh3Au)2(μ-R2bpy)](OTf)2(R2bpy = bpy (1), dbbpy (2), CH3Obpy (3), 3-CO2CH3bpy (4), 4-CO2CH3bpy (5)) in high yields. The crystal structures for all compounds were determined using X-ray diffraction analysis. In all structures, gold ions are in a typical linear environment, and the bipyridine molecule is twisted, which allows intramolecular aurophilic interactions. Relatively short Au(i)⋯Au(i) contacts (3.1262 (2)-3.400 (1) Å) are found in structures3-5. DFT calculations show the presence of bond critical points (3, −1) for aurophilic interactions in these structures. In structures1and2, the Au(i)⋯Au(i) distances are noticeably larger and equal to 4.479 (1) and 4.589 (1) Å respectively; there are no bond critical points (3, −1) for aurophilic interactions. All complexes show photoluminescence in solid state at room temperature when excited at 300 nm in a wide spectral range: from blue or blue-green emission (400-460 nm) for1-4to orange emission (580 mn) for5. The lifetimes of the excited state are in the microsecond range which is characteristic of phosphorescence. TD-DFT calculations reveal that electronic transitions of different nature are responsible for the photoluminescence of these compounds.
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- 1.04 ХИМИЧЕСКИЕ НАУКИ