Pentakis(phenylethynyl)benzene and Hexakis(phenylethynyl)benzene: A Revision Concerning Two Far Too Similar Prototype Hydrocarbons

Abstract

A previously overlooked hydrodehalogenation reaction occurring during the multiple Pd0‐catalysed C−C coupling reaction between phenylacetylene and hexaiodo‐ and hexabromobenzene was found to give pentakis(phenylethynyl)benzene (“pentatolane”) as the major product, but no hexakis(phenylethynyl)benzene (“hexatolane”) under conditions previously claimed to yield the latter hydrocarbon. As an alternative to a viable route to hexatolane described in the literature, an independent synthesis of this hydrocarbon through sixfold Sonogashira coupling of hexakis(ethynyl)benzene with iodobenzene has been developed. Some physical and spectroscopic properties of hexatolane and of the hitherto unknown pentatolane have been determined after thorough purification by HPLC. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

How Do Redox Groups Behave around a Rigid Molecular Platform? Hexa(ferrocenylethynyl)benzenes and Their “Electrostatic” Redox Chemistry

“…Dehalogenation has been frequently encountered in reactions of organometallic ethynyl reagents and hexahalogenobenzenes; [7,11] this effect can possibly be attributed to side electron transfer from the electron-rich organometallic reagent to the bulky pentaethynylated halogenoarene derivative.…”

Shape‐Persistent, Sterically Crowded Star Mesogens: From Exceptional Columnar Dimer Stacks to Supermesogens

“…1GX (X = 1-3): mixture between 1 and guest GX,index (11,12,13): ratio (1:1, 1:2, 1:3) between host 1 and guest GX.…”

Supramolecular polymerization of hydrogen-bonded rosettes with anthracene chromophores: regioisomeric effect on nanostructures

“…21,22 Although this molecular design has merits, such as its applicability to known functional π-conjugated molecules, it is challenging to introduce many arms onto a central unit because the synthesis and purification of the desired multi-arm products from incomplete side products are demanding. 23 An alternative approach towards such multi-arm π-conjugated structures would be supramolecular macrocyclization (supermacrocyclization) of π-conjugated building blocks using directional noncovalent interactions such as hydrogen-bonding. [24][25][26][27][28][29] By using this approach, we may obtain a complex architecture of one-dimensionally stacked supermacrocyclic π-conjugated systems with a high degree of internal order.…”