Chapter 3 is an exploration of the influence of structural modifications on the excited state properties of Pt(II)-acetylide complexes and expands upon the understanding of factors that influence intersystem crossing rates in complexes of this type. Modification of the peripheral group on the naphthalimide ligand from an octyl chain to -PhCOOMe, leads to an increase in the rate of ISC observed from (193 ps)^-1 to (131 ps)^-1. This is partly attributed the increased electron withdrawing ability of the naphthalimide unit, with the aromatic ester group.
Chapter 4 investigates Cl-Pt-CC-NAP-PhCOOMe through 2DIR spectroscopy by excitation of either the carbonyl or the acetylide mode. Cross peaks between the acetylide and carbonyl modes, indicate long range intramolecular energy transfer. Energy transfer from the acetylide mode to the aromatic and carbonyl shows a sequence of population consistent with energy propagation through the molecular structure which is evidenced by the rates of IVR.
Chapter 5 investigates the Photophysics of the organic D-B-A molecule, (OMe)2PTZ-Ph-C≡C-NDI. In aromatic solvents, there is a broad, red-shifted emission band which indicates presence of an aggregate species. In non-aromatic solvents following, excitation to the 1CT state, the molecule undergoes a branched relaxation pathway to form a charge-separated state and secondary state. In toluene, the lifetime of the excited state is prolonged to 140.9 ps from 100-101.9 ps in non-aromatic solvents, likely due to a greater stabilisation of the excited state.
Chapter 6 is a spectroscopic study of pyrene-functionalised polymer brushes (py-PAGEO5MA). Emission spectra show a plateau of excimer emission (475 nm) at concentrations above 0.1 M of pyrene, suggesting, a restriction of pyrene interactions in the rigid polymer. Absorption spectra indicate the presence of aggregates at 392 nm. However, fluorescence lifetime kinetics indicate time-delayed growth of excimer emission indicating the presence of both an excimer and aggregate species in the brush.
