LIQUID-CRYSTALLINE OCTA-(2-ETHYLHEXYLOXY) PLATINUM AND LEAD PHTHALOCYANINES

Abstract

A series of octaalkoxy dihydrogen, copper, platinum, and lead phthalocyanines (Pc's) has been synthesized and characterized by differential scanning calorimetry and polarizing microscopy. The structures and purities of the compounds were established by elemental analysis, thin layer chromatography, UV-visible, and H-1 NMR spectroscopy, and by a new mass spectral method for Pc's: continuous-flow liquid secondary ion mass spectrometry. The branched chain octa-(2-ethylhexyloxy) Pt and Pb Pc's 3 and 4 exist in mesophases from -100 to + 200-degrees-C. X-ray diffraction indicates that the PcPb 4 has a discotic square columnar phase, and is consistent with an oblique discotic phase of the PcPt 3. Langmuir pressure-area isotherms show that the PcPt and the PcPb form monolayers with the Pc plane normal and parallel to the water surface respectively. Solid state C-13 NMR spectra of the mesophases of the octa-(2-ethylhexyloxy) Pt and Pb Pc's have strong dipolar couplings and show that overall molecular reorientations occur at slower than kHz frequencies at temperatures up to 90-degrees-C.