Towards nanometre-scale gratings: synthesis and characterization of dodecyloxy-substituted platinum phthalocyanines

Abstract

Octakis(dodecyloxy)platinum(II) phthalocyanine, (C₁₂H₂₅O)₈PcPt, has been synthesized and its mesomorphic properties have been studied. It exhibits a liquid-crystalline phase from 77 °C to its decomposition temperature ( > 350 °C). X-Ray diffraction at small angles indicates a hexagonal columnar structure (intercolumnar distance 34.3 Å). A fairly narrow ring at 3.29 Å can be associated with the intracolumnar Pt–Pt spacing, indicating an important overlap of the d_z² platinum orbitals. (C₁₂H₂₅O)₈PcPt forms aggregates when dissolved in organic solvents. Dimerization constants have been estimated to be in the range 10⁵–10⁸ dm³ mol^–1.