Qiu-Yan Luo

Synthesis and characterisation of three diiron tetracarbonyl complexes related to the diiron centre of [FeFe]-hydrogenase and their protonating, electrochemical investigations

The synthesis, characterisation of three diiron tetracarbonyl complexes, [Fe2(SCH2)2C(Me)(CH2OR)(PNP)(CO)4] (R = H and PNP = L11: 2; R = H and PNP = L22: 3; R = Ts and PNP = L11: 4) as models for the diiron sub-unit of [FeFe]-hydrogenase are described, where OTs, L11 and L22 are toluenesulfonate, (Ph2P)2NCH2(2-C5H4N) and (Ph2P)2NCH2Ph, respectively. These complexes are fully characterised and the structure of complex 4 is crystallographically determined. Protonation of these complexes with HBF4·Et2O is probed by using infrared and NMR spectroscopies which reveals that no hydride can be formed upon addition of the acid. Instead addition of excess of the acid leads to protonating the N atom of the PNP skeleton, which is a weak base due to participating conjugating interactions with the Fe–Fe centre, as revealed by crystallographic analysis. Electrochemistry of these complexes and their electrocatalytic reduction of protons are also investigated. Our results suggest that the existence of the pendant pyridine group can lower the overpotential for proton reduction but does not seem to enhance electrocatalytic efficiency in our case.

Synthesis and structure of [Nd(C6NO2H5)3(H2O)2]2n· (3nHgCl4) · (4nH2O)

Abstract Hydrothermal reaction of NdCl3 · 6 H2O, HgCl2 and isonicotinic acid gave a bimetallic 4f-5d metal-isonicotinato complex [Nd(C6NO2H5)3(H2O)2]2n · (3nHgCl4) · (4nH2O) (1) and an X-ray crystal structure analysis reveals that it features a one-dimensional polycationic chain-like structure. The crystal belongs to the monoclinic, space group C2/c with a = 24.208(1), b = 20.842(1), c = 15.379(1) Å, β = 127.759(1)°, V = 6134.5(7) Å3, Z = 4, C36H46Cl12Hg3N6Nd2O20, Mr = 2198.44, Dc = 2.380 g/cm3, S = 0.986, μ(MoKα) = 9.738 mm–1, F(000) = 4112, R = 0.0384 and wR = 0.0848. The neodymium atom has a distorted square anti-prism geometry, coordinated by eight oxygen atoms. Each mercury atom is bound by four chlorine atoms to form a HgCl42– tetrahedron. The [Nd(C6NO2H5)3(H2O)2]2n6n+ species, HgCl42– anions and lattice water molecules are held together via hydrogen bonds to form a three-dimensional framework.

Syntheses, structures and photoluminescence of a series of transition metal-cyanopyridine polymers

A series of transition metal-n cyanopyridines (i.e. pyridine-n-carbonitrile; n = 2, 3, 4) complexes with one-dimensional (1-D) structures, [CuCl2(pyridine-3-carbonitrile)2] n , [CuCl2(pyridine-4-carbonitrile)2] n and [CoCl2(pyridine-4-carbonitrile)2] n , have been synthesised via hydrothermal reactions and structurally characterised by single-crystal X-ray diffraction. All these complexes feature infinite 1-D chain-like structures. Photoluminescent investigation reveals that the title complexes display strong emissions which may originate from π→π* charge-transfer interaction of the ligands.

Solvothermal Preparation, Crystal Structure, and Photoluminescence of a Cadmium Compound With a Two-Dimensional Supramolecular Layer

By virtue of a solvothermal reaction, a new cadmium-bipyridinium derivative (N,N′-dimethyl-4,4′-bipyridinium)3(CdCl3-HCl-CdCl3)(CdBr4)2 (1) with the N,N′-dimethyl-4,4′-bipyridinium cation obtained in situ, was synthesized and characterized by X-ray single-crystal diffraction method. The title compound is characteristic of an isolated structure. The anions and cations in 1 are connected through hydrogen-bonding interactions to give a two-dimensional (2-D) supramolecular layer. The fluorescence result discovers a wide emission band in the green region.

Photophysical and electrochemical properties of a dysprosium‐zinc tetra(4‐sulfonatophenyl)porphyrin complex

A dysprosium-zinc porphyrin, [DyZn(TPPS)H3O]n (1) (TPPS = tetra(4-sulfonatophenyl)porphyrin), was prepared through solvothermal reactions and structurally characterized by single-crystal X-ray diffraction analyses. Complex 1 features a three-dimensional (3-D) porous open framework that is thermally stable up to 400 °C. Complex 1 displays a void space of 215 Å(3), occupying 9.2% of the unit cell volume. The fluorescence spectra reveal that it shows an emission band in the red region. The fluorescence lifetime is 39 µsec and the quantum yield is 1.7%. The cyclic voltammetry (CV) measurement revealed one quasi-reversible wave with E1/2  = 0.30 V.

A novel terbium-cobalt tetra(4-sulfonatophenyl)porphyrin: Synthesis, structure and photophysical and electrochemical properties

A novel terbium-cobalt porphyrin {[Tb(H2O)3][Co(TPPS)]}n•nH3O (1) (TPPS = tetra(4-sulfonatophenyl)porphyrin) has been synthesized via a hydrothermal reaction and structurally characterized by X-ray single crystal diffraction. Compound 1 is characterized by a three-dimensional (3-D) porous open framework, which is originated from the Co(TPPS) moieties interconnected by the terbium ions. The fluorescence study shows that compound 1 displays an emission band in the blue region. Nanosecond transient spectra reveals that the fluorescence lifetime is 1.14 ms. The cyclic voltammetry (CV) and differential pulse voltammetry (DPV) experiments discovers one reversible wave with E1/2 = -0.80 V.

Photophysical and electrochemical properties of a novel 4f–3d heterometallic porphyrin

A 4f-3d heterometallic porphyrin, [TbCo(TPPS)H3O]n (1) (H2TPPS = tetra(4-sulfonatophenyl)porphyrin), has been synthesized via a hydrothermal reaction and structurally characterized by single crystal X-ray diffraction analysis. The structure of 1 consists of [TbCo(TPPS)H3O]n molecules. The Tb3+ ions are coordinated by eight oxygen atoms from eight sulfonic groups, yielding a distorted square anti-prism geometry. Compound 1 is characterized by a three-dimensional (3-D) porous open framework that is thermally stable up to 350°C. Compound 1 displays a fluorescent emission band in the ultraviolet region and its fluorescence lifetime is 1.14 ms. A slow scan CV curve of compound 1 reveals one reversible wave with E1/2 being equal to -0.78 V, which is close to the value -0.74 V of DPV diagram.

Bis(μ-carboxyl­atoethyl­phospho­nato)bis­[aqua­(2,2′-bipyridine)manganese(II)]

The title compound, [Mn2(HO3PCH2CH2COO)2(C8H8N2)2(H2O)2], was obtained by hydrothermal synthesis. The manganese(II) ions are six-coordinate and are linked by two 2-carboxyethylphosphonate ligands, forming a centrosymmetric dimer. The Mn ions adopts a distorted octahedral coordination geometry. The dimers are further linked by O—H⋯O hydrogen bonds and π–π stacking interactions [centroid–centroid distance 4.2754 (4) Å].