Abstract: Tetrabromo-2,3-naphthalocyanine lead(PbNcBr₄) was synthesized in the presence of 1, 8-diazabicycloundec-7-ene(DBU) and its electronic absorption spectra, thermal stability, optical limiting property and the effect of bromine substituent on the above properties were investigated.There is one strong Q-absorption band in nearinfrared region.Bromine substituent attached to outer Nc ring results in the Q-band of PbNcBr₄shifting to the blue compared to the complex unsubstituted.The polarity of solvents have influences on the electronic absorption spectra greatly< The complex shows high thermal stabilities and appears to be more stable in N₂(the onset temperature 504.6 ℃) than in O₂(the onset temperature 326.8 ℃).The thermal stabilities decrease on account of bromine substituent attached to outer Nc ring and declining extent changes with the varieties of atmosphere(decreased by 175℃ in N₂, 25 ℃ in O₂).Decomposition mechanisms differ according to the varieties of atmosphere with one step in O₂and multi steps in N_2.At a relatively high linear transmittance of 88%, the limiting threshold is 148mJ/cm², the clamped fluence is 332 mJ/cm², and the damage fluence is about 3J/cm². The optical limiting behavior of PbNcBr₄is better than that of C₆₀whose limiting threshold is above 240 mJ/cm²with a linear transmittance of 70%. It can be regarded as a new kind of materials which has a better optical limiting property.

Key words: Tetrabromo-2,3-naphthalocyanine lead, Thermal stability, Optical limiting property