Monolayer assemblies of several phthalocyanine derivatives, e.g. copper tetrakis(n-butoxycarbonyl)phthalocyanine, showing highly anisotropic absorption spectra have been obtained.

The chemical behaviour of oxotitanium(1v) phthalocyanine (OTiPc) in mixtures of dichloromethane and trihalogenoacetic acids was studied by means of spectroscopic measurements. In dichloromethane-trifluoroacetic acid mixtures, OTiPc was relatively unstable, undergoing gradual decomposition via the radical cation of OTiPc; phthalimide and 3-iminoisoindolin-1 -one were isolated. In dichloromethane-trichloroacetic acid mixed solvent, on the other hand, a stable solution of OTiPc was obtained with no formation of the radical cation. A monolayer of OTiPc was formed upon spreading this solution onto the water surface and was deposited on substrates with a horizontal lifting method to form a multilayer film. Polarized visible and near-IR absorption spectra and X-ray diffraction of the film indicated a specific order of molecular orientation.

Surface modifications of gold-on-glass substrates with organic thin layers exerted remarkable effects on the molecular alignment in the ordered solid films of oxotitanium(IV) phthalocyanine (OTiPc) grown by conventional vapor deposition (VD). While VD onto a gold-on-glass substrate heated at 150 °C gave a highly ordered phase I (β-form) crystalline film with parallel molecular orientations, ordered phase II (R-form) crystalline films with an obliquely standing molecular arrangement were selectively grown on the surfaces of the substrate modified with 9-cycle Langmuir-Blodgett layers of OTiPc, a self-assembled monolayer of octadecanethiol, and a spin-coated thin film of polyimide. Moreover, VD of OTiPc onto a rubbed polyimide film gave an in-plane ordered phase II film in which obliquely standing OTiPc molecules are aligned with the molecular plane parallel to the rubbing direction. This film revealed high dichroic behavior in the p-polarized visible and IR absorption spectra. The substrate-surface effects are discussed in terms of initial formation of "director layers" by interactions of depositing molecules with the organic surfaces.

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