Syntheses And Properties Of New Functional Molecules With Delocalized Sulfur-Rich Core

Compounds with sulfur-rich core (1,3-dithiol ring and tetrathiafulvalene(TTF)) have been used as versatile building blocks in supramolecular and material chemistry, such as molecule based magnetic conductor/semiconductor, organic field-effect transistors (OFETs), intramolecular donor-acceptor (D-A) systems of nonlinear optic (NLO) materials, molecular shuttles, switches, wires and so on. To achieve materials with intriguing structures and interesting properties, a variety of mono-or polydentate coordinating functional groups such as dithiolate, pyridine, bipyridine, N-heterocylic, phosphine, carboxylate, acetylacetonate and schiff-base have been reported as covalent linkages between redox active TTF units and transition metal ions. It is expected that such direct connection will provide possible communications between the inorganic and organic substructures in order to modify or enhance their properties, such as conductive, magnetic, photophysical or photochemical properties. In this dissertation, we report the syntheses and characterization of new functional ligands with delocalized sulfur-rich core and the related metal complexes. The physical and chemical properties of some typical compounds are also discussed.1. A new multidentate ligand:3-[2-(dipyridin-2-yl-methylene)-5-methylsulfanyl-[1,3]dithiol-4-ylsulfanyl]-penta ne-2,4-dione (L1), has been prepared. Through reactions of the ligand with Re(CO)5X (X=Cl, Br), new rhenium(I) tricarbonyl complexes ClRe(CO)3(L1)(1) and BrRe(CO)3(L1(2), have been obtained. With the use of1or2as the precursors, the further reactions with (TpPh2)Co(OAc)(HpzPh2)(TpPh2hydrotris(3,5-diphenylpyrazol-1-yl)borate; HpzPh2=3,5-diphenyl-pyrazole) or M(OAc)2(M=Mn, Zn), afford four new heteronuclear complexes: C1Re(CO)3(L,)Co(Tpph2)(3), BrRe(CO)3(L,)Co(TpPh2)(4),[ClRe(CO)3(L,)]2Mn(CH3OH)2(5) and [ClRe(CO)3(L,)]2Zn(CH3OH)2(6), respectively. Crystal structures of complexes1and3-6have been determined by X-ray diffraction. Their absorption spectra, photoluminescence and magnetic properties have been studied.2. A series of tetrathiafulvalene-substituted acetylacetonate ligands (L2-L5) have been synthesized and characterized. Reactions of the above ligands with (TpPh2)Co(OAc)(HpzPh2) and (TpPh2)Ni(OAc)(TpPh2=hydrotris(3,5-diphenylpyrazol-l-yl)borate; HpzPh2=3,5-diphenyl-pyrazole) afford eight new mononuclear or dinuclear complexes7-14:TpPh2ML2or (TpPh2M)2L (M=Co, Ni; L=L3, L4and L5). The crystal structures of L5and complexes7-9,11and12have been determined by X-ray crystallography. The absorption spectra and redox behaviors of these compounds have been studied. Optimized geometry and electron absorption spectrum of8have also been analyzed by density functional theory (DFT) and time dependent density functional theory (TD-DFT). The values of the calculated energy gaps match well with the UV-vis spectroscopic data.3. Two new bis-3,5-dimethyl-pyrazole-substituted tetrathiafulvalene ligands,2,6(7)-bis(methylthio)-3,7(6)-bis(3-sulfanyl-3,5-dimethylpyrazole) tetrathiafulvalene (cis/trans-L6) and2,3-bis(methylthio)-6,7-bis(3-sulfanyl-3,5-dimethylpyrazole) tetrathiafulvalene (L7), have been prepared and characterized. Based on the two ligands, three interesting rhenium(Ⅰ) tricarbonyl mono-or dinuclear complexes: ClRe(CO)3(cis-L6)(15),[ClRe(CO)3(trans-L6)]2(16) and [ClRe(CO)3(L7)]2(17), are prepared and structurally characterized. Electrochemical studies of sequential oxidation processes suggest that redox events are essentially dependent of structures of rhenium(Ⅰ) complexes. The results have evidenced electronic interactions between the TTF cores in complexes15and16. Geometric and electronic structures as well as the spectroscopic properties for complexes15-17are investigated by using DFT and TDDFT calculations.4. After introducing boron-dipyrromethene (BODIPY) group on tetrathiafulvalene moiety, a new sensor18for anion recognition has been prepared and characterized. The crystal structure of complex18has been determined by X-ray crystallography. The UV-vis absorption shows significant changes of color after the addition of F-. Redox properties are investigated by cyclic voltammetry, and the receptor shows significant F-binding properties with electrochemical shifts. The results show that the sensor with both redox active TTF moiety and recognition subunit leads to the electrochemical and optical response toward F-Theory calculations and1H NMR has also been added to investigate the mechanism of anion recognition.5. A new sensor19has been synthesed successfully by introducing nitrophenylhydrazine on tetrathiafulvalene moiety. The UV-vis absorption and cyclic voltammetry show that it has high selectivity toward fluoride. Compound19is a new dual functional sensor for fluoride.