Multi-Functional Materials Based On Molecular Conductors

With the advantages of low density, easy to adjust and reform, the development of molecular conductor is very breathtaking. The charge transfer complex (mainly based on tetrathiafulvalene and its derivatives), fullerene metal salt, the graphene and carbon nanotubes et al. have been the research object of molecular conductors. As we know, tetrathiafulvalene (TTF) and its derivatives, and1,2-dithiolene complexes, have been used as versatile building blocks in supramolecular and material chemistry, Such as moleculebased magnetic conductor/semiconductor, organic field-effect transistors (OFETs), intramolecular donor-acceptor (D-A) systems of nonlinear optic (NLO) materials, molecular shuttles and switches, and wires, et al.. Meanwhile, Graphene is a two-dimensional single-layer sheet of graphite with p-electrons fully delocalized on the graphitic plane. It is highly conductive and mechanically strong and has been explored extensively for molecular electronic device, energy transfer, energy storage, and catalytic applications. Thus, the emergence of graphene nanosheet has recently opened up an exciting new field in the science and technology of two-dimensional nanomaterials with continuously growing academic and technological impetus. One of the research trends for functional materials is to search for molecules conductors with conductive and magnetic interactions, or excellent catalytic performance et al.. In this dissertation, we choose tetrathiafulvalene and graphene as the research object to construct multifunction system based on molecular conductor, we report the syntheses and design of a series of bidentate ligands and tricarbonyl rhenium(Ⅰ) complexes based on tetrathiafulvalene, new gold(I) and platinum(Ⅱ) thiolate complexes, Pd nanoparticles on graphene. Their photophysical, photochemical and electrochemical properties are also discussed.1. we have successfully prepared a new tetrathiafulvalene-based bipyridine ligand,5-[{2-[4,5-Bis(methylthio)-1,3-dithiol-2-ylidene]-5-(methylthio)-1,3-dithiol-4-yl}-thio-]-methyl-2,2’-bipyridine (Li). The reactions of the ligand L1and Re(CO)5Br or Re(CO)5Cl in toluene afford the corresponding tricarbonyl rhenium(I) complexes, Re(L,)(CO)3X (X=Br,1; X=Cl,2) in high yield (73%and68%), respectively. The metal complexes are characterized by IR and’H NMR spectra. In IR spectra, typical three CO stretching vibrations for Re1tricarbonyl complexes are observed, indicating the facial arrangement of three coordinated C=O ligands. In1H NMR spectra, compared with the free ligand, all H signals of bipyridine ring for the rhenium complexes are shifted0.13-0.40ppm to the lower field, which are in agreement with the decrease of electron density around the bipyridine unit caused by its coordination to the Re(I) ion. The crystal structures of1and2have been determined by X-ray crystallography. Their absorption spectra have also been investigated. The electrochemical studies show that they could be oxidized to the corresponding cation-radical and dicationic species. The results suggest that the TTF-fused bipyridine ligand is useful for the preparation of multifunctional metal complexes.2. we have successfully synthesized the TTF-based pyrazole ligand (L2) and TTF-based pyridine ligand (L3) by the acylation reaction between4’,5’-bis(methylthio)-[2,2’-bi(1,3-dithiolylidene)]-4-carbonyl chloride and an excess of2,2’-bis(pyrazolyl)ethanamine or Bis(pyridin-2-ylmethyl)amine. The1H NMR spectra of L2exhibit signals at6.12ppm, which can be attributed to the proton on the amino group. It is also observed that the shape peak at1566cm-1due to the stretching vibrations of the C=C and C=N bonds of the pyrazole group in infrared spectra. Based on the versatile multidentate ligand L2, a functional rhenium(I) tricarbonyl complex Re(L2)(CO)3Cl3has been synthesized and structurally characterized. In IR spectra, three typical bands (around2025,1919and1882cm-1) found in the CO stretching region for Re(I) complex3are in excellent agreement with the facial arrangement of the three coordinated C=O groups. The crystal structures of the ligand L2and complex3have been determined by X-ray crystallography. Their electrochemical and spectroscopic behaviors have also been studied. The results suggest that the redox-active amide functional tetrathiafulvalene ligands are useful for producing new multifunctional metal complexes.3. we describe the synthesis and properties of two dinuclear gold(Ⅰ) complexes [Au2(μ-L4)(PPh3)2](4) and [Au2(μ-L5)(PPh3)2](5), and two new platinum diiminedithiolate complexes [Pt(dbbpy)(L4)](6) and [Pt(dbbpy)(L5)](7) based on the multi-sulfur dithiolene ligands L4and L5(L4=quinoxaline-2,3-dithiolate, L5=[4/,5/:5,6][1,4]dithiino[2,3-6] quinoxaline-1,3-dithiolate). The crystal structures of three typical complexes4-6have been determined by X-ray crystallography. The spectroscopic behaviors of these complexes have also been studied. The normalized emission spectra of compound5or7are shifted hypsochromically and fluorescence enhancement compared with those of compound4or6, respectively, which can be ascribed to the different substituents. Through changes in the dithiolate ligands and the electron donating and accepting abilities of the ligands, the charge-transfer absorption and emission energies have been tuned, respectively.4. We report here the design and preparation of4.5nm Pd nanoparticles (NPs) by reduction of Pd(acac)2with morpholine borane in oleyamine and1-octadecene. The Pd NPs are assembled on graphene (G) surface via sonicating the NP hexane dispersion and DMF solution of G. The assembled Pd NPs show the redox property change on the G surface, indicating the strong interaction between Pd NPs and G. The G-Pd catalyst shows much enhanced catalysis on electro-oxidation of fomic acid in0.1M HCOOH and0.1M HC1O4with its specific activity reaching2times high as that of the C-Pd NPs. More importantly, the G-Pd NP catalyst is much more stable than the C-Pd catalyst in the electro-oxidation condition. Our work demonstrates the great potential of Gas a support to enhance Pd NP activity and durability for formic acid oxidation reaction (FAOR). The general assembly concept described here can also be extended to other NPs, making it posssible to study and tune G effects on NP catalysis for many different chemical reactions.