Multiple Emissions and Brilliant White Luminescence from Gold(I) O,O ‘ -Di(alkyl)dithiophosphate Dimers

The Au(I) dimers Au2{S2P(OR)2}2 for R = Me, Et are found to exhibit a structure in which aurophilic interactions yield one-dimensional Au···Au chains with intermolecular contacts (3.09−3.16 Å) similar to the Au···Au distances within the dimers (3.10−3.18 Å). The dimers are luminescent in the solid state and become brilliantly emissive at low temperatures. At 77 K, Au2{S2P(OMe)2}2 shows multiple emission bands. The two higher energy bands at 415 and 456 nm are assigned to 1MC and 3MC on the basis of lifetime measurements (20 ns and 2.16 μs, respectively) and concentration-related effects, while the lower energy band at 560 nm is attributed to a LMCT excited state. In frozen glasses of different solvents, Au2{S2P(OMe)2}2 as well as the Et and n-Pr derivatives exhibit a bright luminescence of different colors and striking thermochromism of the emission.