Second, the nature of the spacer becomes less important at especially for mPhTc2 in toluene (Figure ). This effect is 50 less pronounced in the monomers. To be precise, ΦF values 51 for both dimers increase to ca. 30% in toluene and 52 benzonitrile in the absence of O2 (Table ). Among both and). In contrast, the emission of a. Average values of ΦUC-F and standard deviations are obtained from three different measurements.