New highly emissive state of the Mo6X84+ cluster (X= Cl, Br, I)

CHED 1196

Ashley S. Hyme, Ashley.Hyme@otterbein.edu, Nadine M. Stephens, Kellie M. Chenault, Michelle L. Mohler, and Dean H. Johnston, djohnston@otterbein.edu. Department of Chemistry and Biochemistry, Otterbein College, 1 Otterbein College, Westerville, OH 43081
The photophysical properties of a variety of molybdenum halide clusters [Mo6X8Y6]2- (X= Cl, Br, I; Y= Cl-, Br-, I-, CH3SO3-, CF3CO2-, CF3SO3-) have been investigated. Excitation of the clusters at 350nm produces surprisingly rich phosphorescent behavior with emission energy maxima between 675 cm-1 and 825 cm-1, emission quantum yields from 5 to 80%, and emission lifetimes between 70 and 320 microseconds. The photophysical properties are insensitive to the inner halide ligands (X) with the exception of the trifluoroacetate-substituted clusters. The photochemical properties have been analyzed using the Energy Gap Law and the trifluoromethanesulfonate-substituted clusters appear to represent a new, highly emissive state for the Mo6X84+ family.