Selective Synthesis of [12]Cycloparaphenylene

摘要

Shape-persistent, nanosized macrocycles that are composed of only sp- and sp2-hydridized carbon atoms on their perimeter (conjugated molecular loops and belts) have attracted significant attention because of their potential applications in materials science and supramolecular chemis-try.Particularly interesting and challenging among these are aromatic belts and rings as exemplified by the Vogtle belts, cyclophenacenes, cycloparaphenylenes, and cyclacenes. Adding to their sheer aesthetic appeal, these unusual hydrocarbons represent structural models for carbon nanotube segments, and can be envisioned as potential precursors in the preparation of structurally uniform armchair or zigzag carbon nanotubes (Scheme 1). However,despite extensive trials the synthesis of these molecules remains a formidable challenge.