Synthesis Of TTF Derivatives As Dual-Functional Precursors, Preparation And Characterization Of Their Metal Complexes

The origins of dual-property materials of research date back to the molecule tetrathiafulvalene (TTF). Since the discovery of the first organic metal (TTF)(TCNQ), TTF derivatives have been used not only as building blocks of organic conductors, but also as components of molecular machines, organic magnets, organic field-effect transistors (OFET), electrochemical sensors, solar cells, and nonlinear optical (NLO) materials for second-harmonic generation (SHG) applications. Intense investigations are devoted to multifunctional molecular materials. In particular, chemists and physicists are attracted to the design of new molecules and materials that possess synergy or interplay between electrical conductivity with magnetism. The objective of this combination is to establish a coupling between conduction electrons (Ï€electrons) coming from organic donors and localized electrons (d electrons) coming from paramagnetic centers, through the so-calledÏ€-d interaction. To fill this goal, two approaches are investigated: (a) a through-space approach but withÏ€-d interactions that are usually very weak; (b) a covalent link between both systems.Dual-functional materials are of great interest in the area of materials chemistry. In order to design dual-functional materials, four TTF derivatives as the new precursors for the construction of conducting and magnetic materials have been synthesized. Using the 1-(4-(tetrathiafulvaleneyl)phenyl)ethanone (TTF-PEO) and 1-(4-tetrathiafulvalyphenyl)-4,4,4-trifluorobutane-1,3-dione (TTF-ph-tfacH), the preparation of solvent dependent CuBr₄2? charge-transfer salts and the Zinc(II) coordination complex has also been reported, respectively, which can be regarded as an example of the two methods referred above. This report may provide a promising strategy for the design and exploitation of new magnetic compounds for useful applications. The main contents in this thesis can be summarized as follows:1. Four TTF derivatives as the new precursors for the construction of conducting and magnetic materials have been synthesized and chatacterized by NMR and MS, N-(tetrathiafulvalen-4-ylmethylene)-1,2,4-triazol-4-amine (1), 4′-tetrathiafulvaleneyl- 2,2′:6′,2″-terpyridine (2), 1-(4-(tetrathiafulvaleneyl)phenyl)ethanone (TTF-PEO) (3), 1-(4-tetrathiafulvalyphenyl)-4,4,4-trifluorobutane-1,3-dione (TTF-ph-tfacH) (4) with monosubstituted terpyridine heterocycle, triazol heterocycle, acetophenone and acetylacetonate substituents. The cyclic voltammetric analysis of all the compounds 1, 2, 3, and 4 display the two reversible one-electron oxidation waves expected to convert successively the TTF unit into the radical cation and then into the dication. Their electrochemical behaviors are similar to that of TTF, so they should be good donors for conducting materials. They are novel monosubstituted asymmetric TTF-Ï€-A donor molecules with TTF cores, which should be good donors for molecular conductors or OFET potential application.2. The tuning of the charge-transfer of TTF-PEO by solvent was realized forming the mono- and dication complexes (TTF-PEO)₂CuBr₄ (5) and (TTF-PEO)₂(CuBr₄)₂·CH₂Cl₂·CH₃CN (6) in the triclinic PÄ«and the orthorhombic Pbca space group, respectively. These shortest Br···S contacts in 5 might make theÏ€-d interaction between TTF-PEO+·electron-donors and CuII ions possible via Br···S···Br···S super-exchange paths. The antiferromagnetic behavior for monocation radical TTF-PEO+? salt with CuBr₄2? displayed the obvious phase transition at 110-120 K, which is the highest phase transition temperature for a charge-transfer salt with a uniformly monocharged TTF derivative.3. The chelating ability of its enolate anion (TTF-ph-tfac) has been investigated with [MIICl₂·xH₂O] (M = Zn and Co) leading to complexes Zn(TTF-ph-tfac)₂(CH₃OH)₂ (7) and Co(TTF-ph-tfac)₂(CH₃OH)₂ (8), where the metal center is coordinated by two TTF-ph-tfac ligands. This redox active ligand shows promising features for the elaboration of hybrid organic-inorganic building blocks. The magnetic measurement for 8 revealed a nearly perfect paramagnetic system with very weak antiferromagnetic interactions between the centers, which is a precursor for both conducting and magnetic materials.4. Four new copper complexes, the one dimensional (1D) chain complex {[Cu(terpyOH) (phth)]·H₂O}_n (9), the binuclear complex [Cu2(terpyO)₂(phth)(H₂O)₂]·11H₂O (10), mononuclear complexes [Cu(terpyOH)(SO4)(H₂O)]·2H₂O (11) and [Cu(terpyOH)₂]·(HBTC)·2H₂O (12) (terpyOH = 4′-hydroxy-2,2′:6′,2″-terpyridine, phth = phthalate, BTC = 1,3,5-benzene tricarboxylate) have been prepared and characterized by the single crystal X-ray diffraction analysis. In complexes 9, the CuII ions are bridged by phthalate dianions to form infinite Z-shaped chains with terpyOH pendants possessing penta-coordinated distorted square pyramidal geometries. Coexistence of (H₂O)16 and (H₂O)10 water clusters in the complex 10 leads to a novel two dimensional (2D) water sheet. A near-planar S-shape water chain and a zigzag water chain assembled by hydrogen bonds are formed for 11 and 12, respectively. The Cu(II) center in 12 is hexacoordinated, which is quite different from square-pyramidal geometries of complexes 9, 10, and 11. It is interesting to note that 4′-bromo-2,2′:6′,2″-terpyridine was converted into terpyOH in situ under hydrothermal conditions for complex 11. Hence, as discussed above, taking advantage of the terpyOH molecule constructing water cluster, we should adjust the pH to make the terpyOH deprotonated.