Intensely luminescent gold(I)-silver(I) cluster complexes with tunable structural features.
A new series of isostructural, brilliantly luminescent gold-silver complexes having the formula [Au3(mu3-E)Ag(PPh2py)3](BF4)2 where E = O, S, Se and Ph2Ppy = 2-diphenylphosphinopyridine has been synthesized and characterized. The structural core of these complexes is a Au3Ag metallophilically linked tetrahedron with a group-16 atom functioning as a mu3-ligand capping the three gold atoms. In the solid state, pairs of clusters are joined by two unsupported aurophilic interactions. The emission energy changes strikingly in going from O (blue) to S (yellow) and Se (orange). The luminescence from the E = O system is the first to be reported for a gold(I) oxo system. Additionally, the luminescent 4-methylpyridyl analogue with E = S has been prepared and structurally characterized. For E = S, Se, the change in emission energy with mu3-bridging atom provides a sound basis for an LMMCT assignment of the excited state while lifetime measurements support its spin-forbidden nature. Frozen glass measurements indicate the presence of a higher-energy emitting state for these systems, and for the E = O system, either LMMCT or metal-centered cluster-based emission can be proposed.
Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
Quan-Ming
QM
Wang
Young-A
YA
Lee
Olga
O
Crespo
Joseph
J
Deaton
Ching
C
Tang
Henry J
HJ
Gysling
M
M
Concepción Gimeno
Carmen
C
Larraz
M Dolores
MD
Villacampa
Antonio
A
Laguna
Richard
R
Eisenberg