A study was conducted to demonstrate the first selective synthesis of 2,5,8,11-substituted perlylene tetracarboxylic acid bisimides (PBI). A mixture of bis(N-ethylpropyl)PBI and trimethylvinylsilane was heated in mesitylene at 165°C for 60 hours in the presence of of 6 mol% of [RuH2(CO) (PPh3)3]. Tetraalkylated PBI was obtained in 94% yield after silica-gel separation. It was found that the alkylation of N-(2,6-diisopropyl)phenylPBI needed longer reaction times due to its lower solubility, but afforded the desired product in quantitative yield. It was observed that solubility in organic solvents was significantly enhanced after tetraalkylation. It was also found that the alkylation was unable to change the absorption and emission properties in the solution state significantly, but lowered molar extinction coefficients of the lowest energy absorption band.
All Science Journal Classification (ASJC) codes
- Organic Chemistry