Effect of high magnetic fields on intramolecular exciplex fluorescence of pyrene and dimethylaniline systems

The effect of high magnetic fields (〈13 T) on the intramolecular exciplex fluorescence generated from chain-linked pyrene and dimethylaniline systems is studied in acetonitrile. On increasing the magnetic field from 0 to ca. 1 T, the exciplex fluorescence intensity increases and then decreases gradually for fields up to ca. 8 T. The exciplex fluorescence lifetime exhibits a magnetic field dependence similar to that for the intensity (〈13 T). The reversal of the effect in the high magnetic field region is interpreted in terms of a Δg mechanism.