π-Extended Corannulene-Based Nanographenes: Selective Formation of Negative Curvature

Abstract

A geometrically selective bottom-up synthesis of curved nanographenes is described. The synthetic methodology used involves the extension of the π-system of positively curved corannulene by a [4+2] cycloaddition reaction followed by cyclodehydrogenation (Scholl oxidation). By selecting the conditions for the Scholl oxidation, the formation of a sevenmembered ring that also confers negative curvature to the resulting nanographene can be activated, offering two topologically distinct, curved nanographenes from a common precursor. Additionally, the structure−property relationship in these new nanographenes is explored via theoretical, electrochemical, photophysical, Raman, and X-ray crystallographic studies.

Functionalized Contorted Polycyclic Aromatic Hydrocarbons by a One‐Step Cyclopentannulation and Regioselective Triflyloxylation

“…There are few examples on larger PAHs, where selective post‐functionalizing has been reported . In some cases a chlorination as side‐reaction occurs during the cyclization, when FeCl 3 is used as reactant, however, it seems that this is sometimes difficult to be controlled in terms of selectivity and yield …”

Polycyclic aromatic hydrocarbons in the graphene era

“…The single-crystal structure revealed the saddleshaped backbone with a highly distorted naphthalene moiety in the center. Recently, Martín et al [281] reported the synthesis of curved nanographene molecules from corannulene ( Figure 46). The Scholl reaction in the final step led to different products depending on the oxidation conditions.…”

Scholl‐Type Cycloheptatriene Ring Closure of 1,4,9,12‐Tetraarylfenestrindanes: Reactivity and Selectivity in the Construction of Fenestrane‐Based Polyaromatic Saddles

“…These thirteend erivatives possess aryl substituents of varying degrees of electron-donating ability and with different substitution patterns.F urthermore, two unsymmetrical tetraarylfenestrindanes 10 and 12,e ach bearingt wo different kinds of aryl groups,w ere synthesized by using as tepwise Suzuki-Miyaura coupling strategy.T hus, the 1-(3,4-dimethoxyphenyl)-4,9,12tris(3,4-dimethylphenyl) (10)a nd the 1-(2,4-dimethoxyphenyl)-4,9,12-tris(2,3,4-trimethoxyphenyl) (12)d erivatives were obtained in 19 and2 0% yields, respectively,o ver two steps (Scheme 3). All new compounds were characterizedb y 1 Ha nd 13 CNMR spectroscopy and mass spectrometry.I na ddition, the structureo ft etrakis(4-tert-butylphenyl)fenestrindane, 6(4tBu), was characterizedb yX -ray crystallography (seet he Supporting Information). [24] Cyclization of symmetrical substrates Each of the thirteens ymmetrical tetraarylfenestrindanes was submitted to the Schollr eaction conditions (DDQ/TfOH) identical to those used for 6(34diOMe).…”

“…The hydroxy 1 Hr esonances were identified by H/D exchange with deuterium oxide. The methyl, methylene and methine 13 Cr esonances were distinguished by DEPT-90 and 135 experiments. Mass spectra were acquired by ESI or APCI with aT hermo QE xactive Focus Orbitrap, aB ruker SolariX 9.4 TF T-ICR, aB ruker Esquire 3000 Plus Ion Trap, or aS ynapt G2Si Q-IMS-TOFm ass spectrometer.S hown below are the experimental procedure and analytical data for all quadruply cyclized products without bridgehead functionalization.…”