Molecular structure-spectroscopic property relationships in a series of transition metal-containing phenylacetylene oligomers

To develop novel nonlinear dyes for photonic applications, we synthesized a series of transition metal-containing phenylacetylene oligomers. The optical properties of these compounds were measured by UV/Vis, fluorescence, long-pathlength UV/Vis and nanosecond flash photolysis experiments. The sensitivity of the state energies to molecular size was a measure of their delocalization. The S-0 and T-1 states were found to be more localized than the S-1 and T-n states. The results were consistent with the S-0 --> S-1 and T-1 --> T-n transitions having charge transfer character, while the T-1 --> S-0 transition was from a confined state to another confined state. (C) 2001 Published by Elsevier Science B.V.