Step-scan FT-IR time-resolved spectroscopy in the solid state

The use of KBr pellets as an interference-free matrix for performing time-r esolved infrared (TR-IR) measurements on samples in their crystalline state is described and demonstrated. Step-scan Fourier transform infrared time-r esolved spectroscopy ((SFT)-F-2-IR TRS) is used to measure the infrared (IR ) absorption difference (DeltaA, excited state minus ground state) spectra of the Long-lived chargetransfer excited states of polypyridine Ru(II) and Pt(II) complexes pressed into KBr pellets. A comparison of the difference s pectra measured for the metal-to-ligand charge-transfer ((MLCT)-M-3) state of the Ru(II) complex in a KBr pellet vs. acetonitrile (ACN) solution is us ed to validate the technique, The Pt(II) complex could not be analyzed in s olution because of its extremely poor solubility. Thus, these results illus trate one of the significant advantages of performing TR-IR measurements on solid KBr sample pellets.