Solvent-Induced Luminescence and Structural Transformation of a Dinuclear Gold(I) (Aza-18-crown-6)dithiocarbamate Compound.

ABSTRACT

The reaction of AuCl(SMe2) with equimolar NaO5NCS2 [O5NCS2 = (aza-18-crown-6)dithiocarbamate] in CH3CN gave [Au2(O5NCS2)2]·2CH3CN (2·2CH3CN), where six other 2·solvates (solvates = 2DMF, 2DMSO, 2THF, 2acetone, 1.5toluene, and 1.5anisole) can be successfully isolated from different crystal-growing processes (i.e., ether diffusion, layer method, or evaporation in air) by dissolving the dry powder samples of 2·2CH3CN in the respective solvents, and their crystal structures are all determined by X-ray diffraction as well. It is noted that there are different intermolecular Au(I)···Au(I) contacts in combination with various luminescences for 2·solvates and indeed there is a close relationship between intermolecular Au(I)···Au(I) contacts [i.e., 2.8254(7)-2.9420(5) Å] and luminescence energies (i.e., 554-604 nm), including three examples of 2·2CH3CN, 2·0.5m-xylene, and 2·tert-butylbenzene·H2O reported in our previous work. In 2·solvates, the toluene and tert-butylbenzene solvates have the shortest [2.8254(7)-2.8289(7) Å] and longest [2.9420(5) Å] intermolecular Au(I)···Au(I) contacts, respectively, and consequently they show the respective lowest (604 nm) and highest (554 nm) luminescence energies. Indeed, 2·solvates exhibit different types of time-dependent luminescence upon solvate loss in air. Furthermore, B3LYP/LanL2DZ calculation results can help to clarify the relationship between intermolecular Au(I)···Au(I) contacts and luminescence energies for 2·solvates.