Mechanism of Charge Transport in Anisotropic Layers of a Phthalocyanine Polymer

Systematic studies on side-chain structures of phthalocyaninato-polysiloxanes: Polymerization and self-assembling behaviors

A series of dihydroxysilicon phthalocyanines having soluble side chains were synthesized and their bulk-state polymerization capability was investigated. Detailed spectroscopic study of the obtained phthalocyaninato-polysiloxanes revealed that strong electron donating ability and small steric hindrance of the peripheral substituents are the dominant factors to afford high-molecular weight polymers. The polymers show the behaviors of columnar liquid crystal (LC), which is clarified by the presence of clear X-ray diffraction patterns with a hexagonal lattice and birefringent textures in polarized optical microscopy. Because of the siloxane covalent bonds through central silicon atoms, phthalocyaninato-polysiloxanes accommodate one-dimensional phthalocyanine arrays with strong π-electronic couplings, thus exhibiting colmnar LC property even for the derivatives carrying short peripheral chains and leading to the relatively higher density of π-electron systems in the materials. This tendency is different from typical discotic small molecules that require optimum side chain structures for LC formation.

A Capping Methodology for the Synthesis of Lower μ-Oxo-phthalocyaninato Silicon Oligomers

A mixed condensation of a substituted and unsubstituted silicon phthalocyanine monomer, in which the former serves as a "cap" to a growing oligomeric chain, provides unprecedented access to a mixed dimer, trimers, and a tetramer. An important element of product control can be achieved by changing the ratio of the precursor monomers.

Thermally stimulated current investigation of copper octaethylporphyrin dimer Langmuir-Blodgett films

Langmuir-Blodgett films containing meso,meso'-buta-1,3-diyne-bridge Cu(II) octaethylporphyrin dimer have been deposited with the aim of carrying out a thermally stimulated current (TSC) investigation. This characterization was obtained upon cooling samples irradiated by light and others without irradiation: in this way TSC curves have been registered in the temperature range of 100-300 K. Analysis of experimental data has been performed through the application of three different approaches: the initial rate, the heating rate, and Chen's methods. In particular, a trap center at about 0.38 eV has been evidenced and the three different methods have given results in close accordance.