| Tetrathiafulvalene(TTF) shows unique structural and electronic features including the reversible two-step single electron redox potentials, excellent electron donating ability, stable cation radical state, feasible chemical modifications, and tight ?-? stacks in the solid state. Consequently, TTF and it derivatives have attracted tremendous attentions in the past several decades. TTF derivatives have been widely applied as key component in various organic electronic devices, such as organic conductors, superconductors, molecular probes, molecular switches, field effect transistor, photovoltaic cells, and nonlinear optics. On the basis of our progress on the chemistry of TTF derivatives, in the present thesis we report the further investigation on the chemical reactivity and functionalization of aryl-substituted TTF, in order to clarify their chemical stability and explore new functionalities. The main contents the present thesis are as follows:Chapter I: Firstly, we give a brief introduction of the structure characteristics and applications of TTF and its derivatives. Then, we summarize four main strategies to decorate aromatic rings onto TTF skeleton, and outline the different functionalities(optical and electrical properties) created from these strategies. Finally, we introduce our rationale on this thesis including molecular design, synthesis strategy, chemical reactivity, and potential applications.Chapter II: We synthesized an asymmetric TTF derivative(TTF2), which has the electron rich and coordination ligand 3, 4-dihydroxy-substituted phenyl on one side, and electron-withdrawing 3, 5-difluorophenyl on the other side. TTF2 is expected to have the following characteristics:(1) coordination with metal ions to result in the intramolecular charge transfer of “TTF? metal ion”; the hydrogen bonding between the fluorine atom(F) and phenol that could lead to the formation of supramolecular framework. The target compound TTF2 was synthesized in three linear steps with moderate yield. Firstly, the 3,5-difluorophenyl substituted and 3,4-dimethoxyphenyl substituted 1,3-dithiol-2-thiones were prepared via a C u2O-catalyzed C-S coupling reaction. Then, the cross coupling of these two compounds in the presence of P(EtO)3 afforded the asymmetric TTF1. In the final step, the methoxy groups on TTF1 were deprotected by reacts with BBr3 to afford the desired compound TTF2. We have made the thorough investigation on the electrochemical and optical properties of TTF1 and TTF2 under the different conditions. We found that TTF2 show the affinity to various metal ions including Cu(II), Hg(II), Co(II) and so on.Chapter III: We found that TTF derivatives showed ring rearrangement to form a spiro-heterocycle compound by reaction with TEMPO under acidic condition. On the basis of this reaction, we synthesized a series of spiro-heterocycle compounds with different electronic effects and redox potentials, and solved the crystal structure of three representative compounds. We have proposed a most plausible reaction mechanism of the ring rearrangement reaction which includes two main steps:(1) the formation of TTF cation radical in the presence of acid;(2) the ring rearrangement of TTF cation radical induced by TEMPO.Chapter IV: We report the preliminary investigation on the exploration of TTF derivatives bearing β-diketone ligand. We proposed two synthetic approaches toward such TTF derivatives:(1) the C laisen condensation of TTF derivatives having carbonyl or ester groups with the corresponding ester or ketone;(2) the P(OEt)3-mediated coupling of 1, 3-dithiol-2-thione decorated with β-diketone ligand. However, TTF derivatives bearing carbonyl or ester groups show poor solubility in most of organic solvents, consequently the first approach fail to afford the desired compounds. As for the second approach, we have prepared several precursors, i.e., 1,3-dithiol-2-thione decorated with β-diketone ligand. The P(OEt)3-mediated coupling reaction is under investigation. |
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