Cycloparaphenylenes (CPPs): An Overview of Synthesis, Properties, and Potential Applications

Abstract

Cycloparaphenylenes (CPPs) have attracted significant attention from theoretical, synthetic, supramolecular and material chemists owing to their aesthetical structures. Since Jasti and co‐workers reported the landmark synthesis of [9]CPP, [12]CPP and [18]CPP, the past ten years have witnessed a remarkable burst in the development of CPP research, from synthetic methodologies to the applications in optoelectronic devices. In this Focus Review, we highlight the representative synthetic strategies to CPPs and attempts on bottom‐up synthesis of carbon nanotubes (CNTs), and mainly focus on the optoelectronic properties studies of functionalized CPPs as well as heteroatoms doped CPP derivatives. Additionally, the potential applications of CPP derivatives in material science are discussed.

The Supramolecular Chemistry of Strained Carbon Nanohoops

“…8F- [6]CPP,F igure 1) [27] CPP derivatives were reported, thus indicating that the above-described synthetic routes are broadly applicable.F or more detailed information on the syntheses and optoelectronic properties of [n]CPPs,t he reader is referred to several recent review articles. [28][29][30][31][32] Strained nanohoops of an entirely different design comprise meso-substituted porphyrins instead of the phenylene units found in CPPAs and CPPs.A nderson and coworkers have successfully used oligopyridine templates [33,34] to prepare porphyrin nanorings such as c-P5 (Figure 1) by oxidative Glaser reactions.S ince even at emplated ringclosing step is typically not suitable for the generation of very high strain energies, c-P5 may represent the limit of this approach. More strained porphyrin nanohoops were obtained by Osuka and co-workers using the platinum-mediated synthesis strategy commonly used to synthesize CPPs.…”

“…8F‐[6]CPP , Figure ) CPP derivatives were reported, thus indicating that the above‐described synthetic routes are broadly applicable. For more detailed information on the syntheses and optoelectronic properties of [ n ]CPPs , the reader is referred to several recent review articles …”

A Long‐Lived Azafullerenyl Radical Stabilized by Supramolecular Shielding with a [10]Cycloparaphenylene

“…Highly reactive C 59 NC radicals can be shielded by nesting them in carbon nanobelts consisting of single phenyl units connected in para position-cycloparaphenylenes (CPPs). [22][23][24] These convex molecules have been explored for fullerene complexation and the study of photoinduced phenomena. [25][26][27][28][29][30][31] Our approach takes advantage of 1) the 1.4 nm cavity of [10]CPP, resembling the inner space of carbon nanotubes favoring p-p host-guest interactions,t oa ccommodate aC 59 NC radical (Figure 1a), 2) the diminished environmental exposure of the radical resulting from the favorable orientation of the CPPs close to the exposed radical, and 3) the well-established chemistry of C 59 NC,w hich prevents chemical addition to 1,4substituted phenylenes because of steric hindrance.…”

Supramolekulare Chemie von gespannten Kohlenstoffnanoreifen

“…8F‐[6]CPP ; Abbildung ) CPP ‐Derivate publiziert, was noch einmal die breite Anwendbarkeit der oben beschriebenen Syntheserouten zeigt. Für detailliertere Informationen über die Synthesen und optoelektronischen Eigenschaften von [ n ]CPPs seien den Lesern mehrere aktuelle Übersichtsartikel empfohlen …”