SPECTROSCOPIC STUDIES OF LANGMUIR-BLODGETT MONOLAYERS OF PRASEODYMIUM BISPHTHALOCYANINES

Langmuir-Blodgett (LB) monolayers of praseodymium bisphthalocyanine (PrPc2) and a tetra-tert-butyl derivative [4-(t-Bu)4PC]2Pr (or PrPct2) have been prepared and characterized using Raman scattering (RS), surface enhanced resonant Raman scattering (SERRS), and infrared and visible absorption spectroscopies. The green and blue forms of PrPct2 starting material were separated, and the oxidation reduction and acid-base reactivity of the green form of PrPc2 and PrPct2 in solution is reported. Well-characterized LB multilayer assemblies of the green form of PrPc2 and PrPct2 were exposed to NO(x) (NO2/N2O4) gas, and the effect of gas adsorption was monitored using visible and Raman spectroscopies. With the observation of a reversible chemical adsorption of NO2 on a monomolecular LB layer of PrPc2 and PrPct2 complexes, the reversibility of the adsorption reaction for early and late rare earth bisphthalocyanine is confirmed.