Based On Covalently Linked Perylene Imide Aggregate Series Synthesis, Photophysical Properties, And Substituent Effects On The Quantum Chemical Characterization

Photosynthesis is the most important biological process on the earth.The energy human intake to live everyday comes from it.directly or indirectly.And in photosynthetic reaction center,one of the most important processes is the quick and efficient energy transfer.This has attracted many researchers to look for ways to duplicate the reactions in simplified chemical systems.To mimic both the energy transfer and light harvesting process in photosynthetic protein,the artificial photosynthetic system are normally comprised of energy donors and acceptors which linked by covalent bonds or supramolecular interactions.In this thesis,we have prepared a series of perylene tetracarboxylic diimides and their dirivatives,which were covalently linked by different spacer in head-to-tail way. The most significant feature of these compounds is that there is no interaction at gound states although with short distances betweeen perylene units.This will hinder the photoinduced energy transfer and enhance the photoinduced energy transfer between PDI units and provide us an ideal model to study the light havesting properties in a PDI array.In the first part of our work,the research of artificial photosynthesis mechanism and the development of perylene diimides were reviewed.And we introduced the synthesis of a series of perylene diimides and their derivatives,such as their dimer. trimer,dyads and traids,along with their structure characterization.Then the photophysical properties of these series of newly prepared compound were investigated by the steady state electronic absorption,fluorescence spectra and the lifetime measurements.Their absorption spectra suggest that no intense intereaction were revealed between the adject structure unite.While the fluorence and lifetime of these compounds indated that exciting energy migrated from one unite to its adject one in dimer and trimer,while excitd.And the exciting energy transferred from phenoxyl substututed perylene diimides to the piperidinyl substuited one.In the last part of this thesis,density functional thoery(DFT) was calculated at B3LYP/6-31G(d) level to disscuss the substitution effect of different substitutition on the physical properities of perylene diimides.