title: 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(μ2 -pyrazolato-N,N')-tri-gold(I) (1), tris(μ2 -3,4,5- trimethylpyrazolato-N,N')-tri-gold(I) (2), tris(μ2 -3-methyl-5-phenylpyrazolato-N,N')-tri-gold(I) (3) and tris(μ2 -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.
authors.affiliation: Department of Chemistry, University of Bath, Bath BA2 7AY (UK).
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Woodall
authors.forename: Sara
authors.initials: S
authors.lastname: Fuertes
authors.forename: Christine M
authors.initials: CM
authors.lastname: Beavers
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Hatcher
authors.forename: Andrew
authors.initials: A
authors.lastname: Parlett
authors.forename: Helena J
authors.initials: HJ
authors.lastname: Shepherd
authors.forename: Jeppe
authors.initials: J
authors.lastname: Christensen
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Teat
authors.forename: Mourad
authors.initials: M
authors.lastname: Intissar
authors.forename: Alexandre
authors.initials: A
authors.lastname: Rodrigue-Witchel
authors.forename: Yan
authors.initials: Y
authors.lastname: Suffren
authors.forename: Christian
authors.initials: C
authors.lastname: Reber
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Hendon
authors.forename: Davide
authors.initials: D
authors.lastname: Tiana
authors.forename: Aron
authors.initials: A
authors.lastname: Walsh
authors.forename: Paul R
authors.initials: PR
authors.lastname: Raithby
keywords: aurophilicity; crystallography; gold; high pressure; luminescence