To develop a structure-spectroscopic property relationship in platinum acetylides having poly(aromatic hydrocarbon)
ligands, we synthesized a series of chromophores with systematic variation in the number of fused aromatic rings(nFAR)
and ligand topology(polyacene(L), polyphenanthrene(Z) or compact(C)). We measured ground state absorption,
fluorescence and phosphorescence spectra. We also performed nanosecond and picosecond flash photolysis
experiments. To extend the range of compounds in the structure-property relationship, we did DFT calculations on an
expanded series of chromophores to calculate the S1 and T1 state energies. In both the DFT results and experiment, the
ground state and phosphorescence spectra are a function of both nFAR and ligand topology. In the L chromophores, the
S1 and T1 state energies decrease linearly with nFAR. In contrast the S1 and T1 state energies of the Z chromophores
oscillate with increasing nFAR. The C chromophores have behavior intermediate between the L and Z chromophores.
The picosecond transient spectra show complex behavior, having spectra reflecting intersystem crossing, vibrational
cooling and solvent relaxation processes. The nanosecond transient spectra result from the T1 - Tn transition. The timeresolved
spectra show no systematic variation with structure, showing more complex behavior than previously studied
platinum acetylides having phenylene ethynylene ligands.