Synthesis And Quantum Chemistry Study Of Perylene Diimide Derivatives

Perylene tetracarboxylic acid diimide (PDI) derivatives are important molecular building blocks.Because they have low light and thermal fading rates, high luminescence efficiency, wide absorption and emission bands in visible region, and optoelectronic properties. They have been used in organic light emitting diodes(OLED), organic field-effect transistors(OFET), photovoltaic devices, and robust organic dyes that are resistant to photobleaching. In the past decade, PDI derivatives have attracted great interests for chemical and physical workers.Driven by their use in many different applications, the structure of PDIs has been modified by introducing side groups to get appropriate PDIs bearing desirable optical and redox features. Generally, two different methods were adopted to achieve the chemical modification of PDI derivatives. First is introduce different substituents at N atoms of imide groups. This method does not significantly affect the oprtical and electronic properties. The second methos is to introduce the substituents to the perylene core of PDI, i.e., the so-called bay position; such modification will not only greatly improve solubility in organic solvent, but also greatly change the properties of PDIs.Chapter 1:an overview of the basic properties of PDI and its derivatives, research background, synthetic methods and applications.Chapter 2:Synthesis of four PDI derivatives with piperidinyl and pyrrolidinyl at the 1,6-and 1,7-bit bay position, compared the various properties of the four PDI derivatives with similar structres, including steady-state absorption and fluorescence spectra, fluorescence quantum yield and fluorescence lifetime, electronchemical properties, crystal stucture and DFT calculations. The results show that the pyrrolidinyl and piperidyl substitutd crystal sturcture have small difference, but this small difference led to large difference exist between the nature of these compounds. The pyrrolidinyl substituted PDI, Cl-N3 bond length more shorter and nitrogen atom has more SP2 hybrid orbital nature compared with the piperidine substitution. Therefore, the lone pair of the pyrrolidinyl nitrogen atom has more intense conjugate interaction with the perylene. These results can provide a better idea for design new perylene diimide derivatives.Chapter 3:A series of PDI derivatives were investigated by density functional theory calculations, the substitutions are phenyl and phenylethynyl conjugated chain. Substituents cause a great impact on photochemcial and photophysical properties of PDls, made the absorption wavelength and emission wavelength movement on the long wavelength region.Chaper 4:The charge transfer efficiency of a series of PDI derivatives are calculated by density functional theory, obtained the ionization potential and electron affinity of these PDI derivatives, the HOMO and LUMO frontier molecular orbital levels, hole and electron reorganization energy, and the final hole and electron mobility. Compound A-CN and B-CN has a smaller hole and electron reorganization energy, and their electron affinity higher. Compound A has the highest electron moblity. while compound B has the highest hole mobility.