A reversible polymorphic phase change which affects the luminescence and aurophilic interactions in the gold (I) cluster complex, [mu3-S(AuCNC7H13)3](SbF6).
Crystallographic examination of [mu3-S(AuCNC7H13)3](SbF6) shows that it undergoes a reversible phase change from orthorhombic to monoclinic upon cooling. At 190 K, the structure shows that two cations self-associate to form a pseudo-octahedral array of six gold atoms connected by both intra- and interionic aurophilic interactions. On cooling, the clusters become less symmetric, and in one, the interionic Au...Au separations increase, while they decrease in the second cluster. The luminescence of crystalline [mu3-S(AuCNC7H13)3](SbF6) shows corresponding changes in emission, with two emissions of similar lifetimes but with different excitations at 77 K, but only a single emission at 298 K. In contrast, [mu3-S(AuCNC6H11)3](PF6), which has a similar structure to that of the high-temperature form of [mu3-S(AuCNC7H13)3](SbF6), does not undergo a phase change or change in its luminescence upon cooling.
Gussenhoven
Emily M
EM
Department of Chemistry, University of California-Davis, One Shields Avenue, Davis, CA 95616, USA.
Fettinger
James C
JC
Pham
David M
DM
Malwitz
Mark A
MA
Malwitz
Mark M
MM
Balch
Alan L
AL