63018-98-4Relevant academic research and scientific papers
Superacid-catalyzed dimerization/cyclization of isopropenyl-PAHs - Novel pathways to PAH dimers, phenalenes and their stable carbocations
Brule, Cedric,Sultana, Fatima,Hollenstein, Sandro,Okazaki, Takao,Laali, Kenneth K.
experimental part, p. 3700 - 3708 (2009/04/11)
The isopropenyl derivatives of representative classes of polycyclic aromatic hydrocarbons (PAHs) having four and five fused-ring systems, namely pyrene, chrysene, benzo[c]phenanthrene (BcPh), dibenzo[a,c]anthracene (benzo[f]tetraphene) and perylene, were synthesized by Wittig olefination from the corresponding acetyl-PAHs. Under the influence of triflic acid (TfOH), the isopropenyl derivatives were converted to novel PAH dimers and/or phenalenes in a simple one-pot procedure. A plausible mechanism for this process has been outlined, and the synthetic scope of this chemistry has been explored. Structural features in the PAH dimers were examined by DFT. As representative initial and final carbocation intermediates in the reaction sequence, stable carbocations derived from 3-isopropenylperylene and from 4,6,6-trimethyl-6H- dibenzo[a,kl]anthracene were generated and studied directly by NMR spectroscopy. The NMR characteristics and charge delocalization modes in the resulting benzylic carbocations are discussed. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
High temperature gas phase syntheses of C20H12 cyclopenta-fused polycyclic aromatic hydrocarbons: Benz[l]acephenanthrylene and benz[j]acephenanthrylene and their selective rearrangement to benzo[j]fluoranthene
Sarobe, Martin,Jenneskens, Leonardus W.,Wesseling, Jolanda,Wiersum, Ulfert E.
, p. 703 - 708 (2007/10/03)
The novel C20H12 cyclopenta-fused polycyclic aromatic hydrocarbon benz[l]acephenanthrylene (2) and its isomer benz[j]acephenanthrylene (3) have been obtained by flash vacuum thermolysis of 2-(1-chloroethenyl)benzo[c]phenanthrene (6) and 6-(1-chloroethenyl)chrysene (7), respectively. At T ≥ 900°C 2 and T ≥ 1000°C 3 rearrange selectively to the abundant combustion effluent benzo[j]-fluoranthene (1). No evidence for the presence of the related rearrangement products benz[l]aceanthrylene (12) and benz[j]aceanthrylene (13), respectively, is found. Semi-empirical AM1 calculations provide a rationalization for these observations; the conversion of 2 and 3 into 1, instead of 12 and 13, respectively, via consecutive ring-contraction-ring-expansion processes and vice versa is favoured.
