RESONANT NONLINEAR OPTICAL-PROPERTIES OF SPIN-CAST FILMS OF SOLUBLE OLIGOMERIC BRIDGED (PHTHALOCYANINATO)RUTHENIUM(II) COMPLEXES

Spin-cast films of the oligomeric bridged (phthalocyaninato)ruthenium(II) complex [t-Bu4PcRu(dib)]n, which is axially linked by a p-diisocyanobenzene (dib) bridging ligand, were investigated by degenerate four wave mixing with laser wavelengths varied over the complete range of the Q-band absorption and by third harmonic generation at 1064 nm. The magnitudes of chi(3)(-3-omega;omega,omega,omega) and chi(3)(-omega;omega,omega,-omega) and characteristic dependence on the absorption coefficient alpha(omega) were determined. By comparison with other lower-dimensional organic materials with a conjugated pi-electron system, we conclude that the optical properties of this [t-Bu4PcRu(dib)]n oligomer are mainly determined by the two-dimensional character of the phthalocyanine units, which behave as saturable absorbers with a relaxation time of 70 +/- 5 ps.