Dynamic Au–C σ-Bonds Leading to an Efficient Synthesis of [n]Cycloparaphenylenes (n = 9–15) by Self-Assembly

Abstract

The transmetalation of the digold(I) complex [Au 2 Cl 2 (dcpm)] ( 1 ) (dcpm = bis(dicyclohexylphosphino)methane) with oligophenylene diboronic acids gave the triangular macrocyclic complexes [Au 2 (C 6 H 4 ) x (dcpm)] 3 ( x = 3, 4, 5) with yields of over 70%. On the other hand, when the other digold(I) complex [Au 2 Cl 2 (dppm)] ( 1′ ) (dppm = bis(diphenylphosphino)methane) was used, only a negligible amount of the triangular complex was obtained. The control experiments revealed that the dcpm ligand accelerated an intermolecular Au(I)–C σ-bond-exchange reaction and that this high reversibility is the origin of the selective formation of the triangular complexes. Structural analyses and theoretical calculations indicate that the dcpm ligand increases the electrophilicity of the Au atom in the complex, thus facilitating the exchange reaction, although the cyclohexyl group is an electron-donating group. Furthermore, the oxidative chlorination of the macrocyclic gold complexes afforded a series of [ n ]cycloparaphenylenes ( n = 9, 12, 15) in 78–88% isolated yields. The reorganization of two different macrocyclic Au complexes gave a mixture of macrocyclic complexes incorporating different oligophenylene linkers, from which a mixture of [ n ]cycloparaphenylenes with various numbers of phenylene units was obtained in good yields.

Ein vierfacher Gold(I)−Aryl‐Makrozyklus mit hyperbolischer Geometrie und dessen reduktive Eliminierung zu einem Kohlenstoffnanoring‐Wirt

“…Über die Bildung verschiedener Ringgrößen und die geringen Ausbeuten wurde bereits häufig in anderen Beispielen der Platin‐vermittelte Makrozyklisierung berichtet [41, 42, 44, 61, 62] . Daher entschieden wir uns die Gold(I)‐vermittelte Makrozyklisierung einzusetzen und beabsichtigten zunächst eine Cyclotrimerisierungsstrategie mit dem Ziel der Bildung eines dreieckigen Makrozyklus [47, 48] …”

“…[41,42,44,61,62] Daher entschieden wir uns die Gold(I)-vermittelte Makrozyklisierung einzusetzen und beabsichtigten zunächst eine Cyclotrimerisierungsstrategie mit dem Ziel der Bildung eines dreieckigen Makrozyklus. [47,48] Die Reaktion von [63,64] Der innere zentrale Durchmesser von ca. 16 Å ist mit dem von [12]CPP vergleichbar und das Packungsmuster zeigt eine versetzte Stapelung einer röhrenartigen Anordnung der Ringe.…”

A Fourfold Gold(I)−Aryl Macrocycle with Hyperbolic Geometry and its Reductive Elimination to a Carbon Nanoring Host

“…These values are in the range as for earlier reported triangular structures and determine the hyperbolic geometry of this fourfold macro-cycle with corner angles significantly below 90°. [47,48] This demonstrates the rigidity between the two Au I centers imposed by the aurophilic interactions in this complex while flexibility originates from the [6]CMP subunits (torsional freedom around the phenyl-phenanthrenyl bonds, Figure 3a). Complex 2-Au has two chirality axes formed by the twisted Au 2 P 2 C five-membered rings of the two corners in the asymmetric unit.…”

Half-substituted fluorocycloparaphenylenes with high symmetry: Synthesis, properties and derivatization to densely substituted carbon nanorings

“…In 2020, the group of Tsuchido and Osakada reported a unique CPP synthesis via macrocyclic gold complexes. [14,15] We found that the Tsuchido-Osakada method is suitable in the synthesis of F12[6]CPP (2). Thus, (2,2',3,3'-tetrafluoro-[1,1'-biphenyl]-4,4'-diyl)diboronic acid was treated with [Au2Cl2(dcpm)] (dcpm = bis(dicyclohexylphosphino)methane) in the presence of Cs2CO3 (1:1:6 molar ratio) in toluene/ethanol/water at 50 °C to produce the corresponding hexagold(I) complex, [Au2(C6F2H2-C6F2H2)(dcpm)]3.…”