Description
1,4,5,8-Naphthalenetetracarboxylic dianhydride (NTCDA) has a naphthalene core with four carboxylic acids at the 1, 4, 5, and 8 positions, with each adjacent carboxylic acid forming an anhydride. NTCDA is aromatic, stable, planar, and highly symmetric chemically, and also possesses favourable electrical properties. Due to the electron-deficient nature of the carboxyl group, NTCDA is known to be a strong electron acceptor molecule with an electron affinity as high as 4.0 eV. It has been demonstrated that NTCDA significantly improves the electrical conductivity of co-deposited thin films of NTCDA and a wide range of metals including indium, magnesium and aluminium. The high electron conductivity of co-deposited NTCDA/In films also strongly suggests that co-deposited NTCDA/In films are excellent electron transport layers for organic light emitting diodes and photovoltaic devices.
Synthesis
General procedure: 100.0 g of a mixture consisting of 1,4,5,8-naphthalenetetracarboxylic acid and 1,4,5,8-naphthalenetetracarboxylic acid monoanhydride (mass ratio 86:14) was added to a 1000 mL three-necked flask with 200 mL of N,N-dimethylacetamide and 400 mL of toluene as solvent. The mixture was heated to 111 °C under nitrogen protection and the reaction was stirred at this temperature for 2 hours. After completion of the reaction, the reaction solution was cooled to 10 °C and stirring was continued for 1 hour. Subsequently, the precipitate was collected by filtration to afford 73 g of 1,4,5,8-naphthalenetetracarboxylic dianhydride.
