Synthesis and Structural Characterization of Hexa-tert-butyl- hexa-peri-hexabenzocoronene, Its Radical Cation Salt and Its Tricarbonylchromium Complex
✍ Scribed by Peter T. Herwig; Volker Enkelmann; Oliver Schmelz; Klaus Müllen
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- English
- Weight
- 369 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0947-6539
No coin nor oath required. For personal study only.
✦ Synopsis
The hexa-tert-butyl substituted hexa-peri-hexabenzocoronene was synthesized in an overall yield of 83 % from 4-tert-butylphenylacetylene. The key step was the oxidative cyclodehydrogenation of hexa(4-tert-butylphenyl)benzene with anhydrous FeCl 3 in CH 2 Cl 2. The high solubility of hexa-tertbutyl-hexa-peri-hexabenzocoronene in common organic solvents allowed a comprehensive spectroscopic characterization of this compound in solution.
Electrochemical oxidation at À 30 8C in the presence of tetrabutylammonium hexafluoroarsenate led to the formation of a stable radical cation salt. Reaction of hexa-tert-butyl-hexa-peri-hexabenzocoronene with an excess of tricarbonyl-(naphthalene)chromium in THF/diox-ane afforded a mixture of mono-and bis-tricarbonylchromium complexes which could be separated by chromatography. The molecular structures of the parent compound, its radical cation salt and its mono-tricarbonylchromium complex were determined by X-ray analysis and discussed in detail. Remarkably, the crystal structures of these compounds are mainly dominated by the formation of dimers of the aromatic cores.