Low temperature emission spectra of 2-pyridyl-substituted platinum-1,2-enedithiolates

The emissions from the 2-pyridyl- and 2-pyridinium-substituted platinum-1,2-enedithiolate complexes, L2Pt{S2C2(2-pyridyl(ium))(R)} where L=PPh3, PPh2Me, PPhMe2, P(propyl)3 and L2=dppm, dppe, and dppp were studied in DMM (DMF–CH2Cl2–MeOH, 1:1:1, v/v/v) glasses at 77 K. All of the pyridyl-substituted complexes have an emission between 18,600 and 17,900 cm−1 with pronounced 1200 cm−1 vibronic structure. The lifetimes of the pyridyl-substituted complexes are 216–350 μs. The pyridinium-substituted complexes have emissions in the range of 16,600–16,100 cm−1 with less resolved vibronic structure than their pyridyl counterparts. The lifetimes of the pyridinium-substituted complexes are 158–290 μs. The emission at 77 K from both the pyridyl- and pyridinium-substituted complexes contrasts with the room temperature studies where only selected pyridinium complexes were emissive.