Supramolecular Chemistry And Self-assembly Special Feature: Pillared honeycomb nanoarchitectures formed on solid surfaces bythe self-assembly of lipid-packaged one-dimensional Pt complexes

摘要

A highly lipophilic polyion complex [Pt(en)2][PtCl2(en)2](1)4 (en, 1,2-diaminoethane) is prepared from one-dimensional mixed valence Pt^II/Pt^IV complex and newly designed chiral amphiphile 1. The powdery sample showed purple color, which is a result of the mixed valence absorption of the linear chlorobridged complex (Pt^II-Cl-Pt^IV-Cl-)n. When the lipid complex is dispersed in dichloromethane, purple-colored dispersion is obtained at 0°C, whereas the color disappears after heating the solution to 21°C. The observed thermochromism is reversible with respect to the temperature changes and is ascribed to the reversible dissociation and reassembly of the self-assembling inorganic wires. Casting of the 0°C-purple dispersion on solid substrates affords honeycomb nanostructures in addition to the nanowires with the width of about 20 nm. The honeycomb patterns seem to be templated by the condensed water droplets that are formed and aligned on the rapidly evaporating dichloromethane solution. On theother hand, more regular honeycomb structures are exclusively obtainedby casting the 21°C-colorless solution. These observationsindicate that the ordered honeycomb structures are obtainable onsolid surfaces by the self-assembly of molecularly dispersed components[Pt(en)2](1)2 andtrans-[PtCl2(en)2](1)2.Very interestingly, formation of double-layered honeycomb nanostructureis observed by scanning electron microscopy. The unit hexagons andpillars of the honeycombs are made of nanowires that are hierarchicallyassembled from the lipid-packaged Pt^II/Pt^IVcomplexes. The surface self-organization of lipophilic inorganiccomplexes has a potential to fabricate novel nanoarchitectures withconjugated electronic structures.