Tunable trimers: using temperature and pressure to control luminescent emission in gold(I) pyrazolate-based trimers.

ABSTRACT: A systematic investigation into the relationship between the solid-state luminescence and the intermolecular Au???Au interactions in a series of pyrazolate-based gold(I) trimers; tris(?2 -pyrazolato-N,N')-tri-gold(I) (1), tris(?2 -3,4,5- trimethylpyrazolato-N,N')-tri-gold(I) (2), tris(?2 -3-methyl-5-phenylpyrazolato-N,N')-tri-gold(I) (3) and tris(?2 -3,5-diphenylpyrazolato-N,N')-tri-gold(I) (4) has been carried out using variable temperature and high pressure X-ray crystallography, solid-state emission spectroscopy, Raman spectroscopy and computational techniques. Single-crystal X-ray studies show that there is a significant reduction in the intertrimer Au???Au distances both with decreasing temperature and increasing pressure. In the four complexes, the reduction in temperature from 293 to 100?K is accompanied by a reduction in the shortest intermolecular Au???Au contacts of between 0.04 and 0.08?Å. The solid-state luminescent emission spectra of 1 and 2 display a red shift with decreasing temperature or increasing pressure. Compound 3 does not emit under ambient conditions but displays increasingly red-shifted luminescence upon cooling or compression. Compound 4 remains emissionless, consistent with the absence of intermolecular Au???Au interactions. The largest pressure induced shift in emission is observed in 2 with a red shift of approximately 630?cm(-1) per GPa between ambient and 3.80?GPa. The shifts in all the complexes can be correlated with changes in Au???Au distance observed by diffraction.

SUBMITTER: Woodall CH 

PROVIDER: S-EPMC4288234 | biostudies-literature | 2014 Dec

REPOSITORIES: biostudies-literature