| With the rapid development of electronics, information science and material science, the design and synthesis of new multifunctional molecular materials with an interplay or synergy between two or more properties have attracted increasing attention. In particular, the construction of such molecular materials combining magnetic and conductive properties in the same crystal lattice has been one of the most important challenges in the field. Tetrathiafulvalene (TTF) and its derivatives have been intensively studied for long time, due to their unique ?-electron donor and redox properties. One of the research trends in new TTF derivatives for functional materials is to search for molecules with more ?-extended systems. On the one hand, they may lead to molecular conductivity through interchalcogen-atom interactions, which are often observed in molecule based conductors and superconductors. On the other hand, electrochemically active TTF units can be used to link magnetic centers to form many interesting structures and multifunctional materials such as magnetic semiconductors or magnetic conductor. In this dissertation, we report the syntheses and characterization of new ?-conjugated TTF ligands and related metal complexes. The physical and chemical properties of the new compounds are also discussed.1. Reaction of [Mn(TTF-salphen)][OAc] (TTF-salphen2-= 2,2'-((2-(4,5-bis(methylth io)-1,3-dithiol-2-ylidene)-1,3-benzodithiole-5,6-diyl)bis(nitrilomethylidyne)bis(phen olate)dianion) and the cyanometalate building blocks [n-Bu4N][(Tp)Fe(CN)3] (Tp-= Tris(pyrazolyl) hydroborate) or [n-Bu4N][Ru(salen)(CN)2] (salen2-= N,N'-ethylenebis(salicylideneimine) dianion) resulted in the formation of two redox-active complexes, the dinuclear heterometallic complex [(Tp)Fe(CN)3Mn(TTF-salphen)CH3OH] (1) and the one dimensional complex [Ru(salen)(CN)2Mn(TTF-salphen)]n (2). Both complexes were fully characterized by X-ray crystallography and solid state electrochemistry, as well as static and dynamic magnetic measurements. Antiferromagnetic couplings are operative between metal ion centers bridged by cyanide in both complexes. Complex 1 exhibits field-induced SMM behavior with an energy barrier of 13.8 K.2. The ?-conjugated tetrathiafulvalene (TTF) annulated ligand is introduced into dicyanometallate for the first time, and the versatile redox-active dicyanideferrite building block [(n-Bu)4N][Fe(TTFbp)(CN)2] (3) (H2TTFbp.= N-(2-(4,5-bis(methylthio)-1,3-dithiol-2-ylidene)-5-(picolinamido)benzo[d][1,3]dithiol-6-yl) picol inamide), has been successfully synthesized. Based on it and chiral Mn1" Schiff-base complexes, two enantiopure one-dimensional complexes, [Mn((R,R)-salphen)Fe(TTFbp)(CN)2]n (4-(RR)) and [Mn((S,S)-salphen)Fe(TTFbp)(CN)2]n (4-(SS)) (Salphen= N,N'-1,2-diphenylethylene-bis(salicylideneiminato) dianion), are synthesized and structurally characterized. Circular dichroism (CD) and vibrational circular dichroism (VCD) spectra confirm the enantiomeric nature of the optically active complexes. Structural analyses reveal the formation of neutral cyanide-bridged zigzag double chains in 4-(RR) and 4-(SS). Solution and solid state CV studies reveal the redox-active properties of the complexes. Magnetic measurements reveal that antiferromagnetic couplings between Fe? and Mn? centers are present within a chain, and a field-induced magnetic phase transition is observed (TN= 4.8 K).3. The oxamato unit has been introduced into a tetrathiafulvalene (TTF) system for the first time via direct condensation, generating a new ?-extended TTF ligand, TTF-Et2H2opba (opba= ortho-phenylenebis-oxamato). On the basis of this ligand, the Cu? complex [(n-Bu)4N]2[Cu(TTF-opba)] (5), has been obtained. By employing this complex as a "metalloligand", we have successfully prepared an interesting heterometallic one-dimensional complex{[Cu(TTF-opba)][Mn(CH3OH)2]}n (6), via coordination of the free carbonyl-oxygen atoms of the two oxamato groups with Mn(II) ions. The new compounds have been structurally characterized, and their electrochemical and magnetic properties probed. Complex 6 shows a ferrimagnetic behavior with g= 1.96 and J=-22.36 cm-4. The new ?-extended redox-active ligand with both TTF and triazole units, (6-(4,5-bis(propylthio)-1,3-dithiol-2-ylidene)-1H-[1,3]dithiolo[4',5':4,5]benzo [1,2-d] [1,2,3]triazole (L3), has been successfully prepared. Based on the versatile ligand and Cu(tta)2 precursors (tta-= 4,4,4-trifluoro-l-(thiophen-2-yl)butane-l,3-dione), a TTF-based pentanuclear Cu? cluster (Cu5(tta)4(TTFN3)6) (7) is synthesized and structurally characterized. Their absorption and electrochemical properties are investigated. Antiferromagnetic couplings are operative between metal ion centers bridged by triazoles in the complex. The self-assembled structure of the cluster complex on a highly oriented pyrolytic graphite (HOPG) surface was observed using scanning tunneling microscopy and density functional theory (DFT) calculations have been performed to provide insight into the formation mechanism.5. We synthesize a new electrochemical ligand based on the TTF unit, L4 (3,3'-(((2-(4,5-bis(methylthio)-1,3-dithiol-2-ylidene)benzo[d][l,3]dithiole-5,6-diyl)bis(azanediyl)) bis(methanylylidene))bis(pentane-2,4-dione)). By introducing the ligand and TPPE (1,1,2,2-tetrakis(4-(pyridin-4-yl)phenyl)-ethene) precursor into the SCO systems, we got two coordination polymers with different stuctures. These complexes were structurally characterized by X-ray diffraction analyses. Compound 9 (Fe(L4)(TPPE)0.5) features 2D square layers, while compound 10 (Fe3(L4)3(TPPE)i.5) possesses a 2D and 3D interpenetrating frameworks. The magnetic and luminescent properties were also investigated for the compounds. Compound 9 displays a gradually SCO behavior and fluorescent properties, in particular showing a coupling between the transition temperature of SCO and the temperature where the fluorescent intensity reverses. Additionally, it reveals the relationship of fluorescent and redox properties. |
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