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- Chen, Ruikui, et al.
(author)
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Photoinduced intramolecular charge-transfer state in thiophene-π-conjugated donor-acceptor molecules.
- 2008
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In: Journal of Molecular Structure. - : Elsevier BV. - 0022-2860 .- 1872-8014. ; 876:1-3, s. 102-109
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Journal article (peer-reviewed)abstract
- Novel thiophene-π-conjugated donor-acceptor mols., 5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-vinyl]-thiophene-2-carbaldehyde (QTC) and (1-cyano-2-{5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-vinyl]-thiophen-2-yl}-vinyl)-phosphonic acid di-Et ester (QTCP), were designed and synthesized. Combined exptl. and theor. methods were performed to investigate the photoinduced intramol. charge-transfer (ICT) processes of these compds. Steady-state absorption and fluorescence measurements in different solvents indicate the photoinduced ICT characters of QTC and QTCP. Solvent dependency of the large Stokes shifts and high dipole moment of the excited state also support the charge-transfer character of the excited state. Theor. calcns. based on time-dependent d. functional theory (TDDFT) method were performed to investigate ICT states of these compds. The results reveal that the excited states have adopted a distortion of the C=C double bond between the donor moiety and the thiophene-π-bridge. [on SciFinder(R)]
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| 4. |
- Ekström, Jesper, et al.
(author)
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Bio-inspired, side-on attachment of a ruthenium photosensitizer to an iron hydrogenase active site model
- 2006
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In: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; :38, s. 4599-4606
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Journal article (peer-reviewed)abstract
- The first ruthenium - diiron complex [(mu- pdt) Fe-2(CO)(5){PPh2(C(6)H(4)CCbpy)} Ru(bpy)(2)](2+) 1 (pdt = propyldithiolate, bpy = 2,2'-bipyridine) is described in which the photoactive ruthenium trisbipyridyl unit is linked to a model of the iron hydrogenase active site by a ligand directly attached to one of the iron centers. Electrochemical and photophysical studies show that the light-induced MLCT excited state of the title complex is localized towards the potential diiron acceptor unit. However, the relatively mild potential required for the reduction of the acetylenic bipyridine together with the easily oxidized diiron portion leads to a reductive quenching of the excited state, instead. This process results in a transiently oxidized diiron unit which may explain the surprisingly high light sensitivity of complex 1.
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| 5. |
- Li, Fie, et al.
(author)
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Synthesis, structure and catalytic property of an iron(II) complex with an N4O2 ligand for alkane oxidation
- 2006
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In: Wuji huaxue xuebao. - 1001-4861. ; 22:10, s. 1899-1904
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Journal article (peer-reviewed)abstract
- Two iron(II) complexes [Fe(tpdoen)](FeCl4)Cl (2, tpdoen=NN-bis(2-pyridylmethoxyethyl)-N-(2-pyridylmethyl)amine) and [Fe(tpdoen)](ClO4)(2) (3) with an N4O2 ligand containing two potentially pi-coordinate oxygen atoms were synthesized as functional models of non-heme iron oxygenases. The X-ray crystal structure analysis corroborated that complex 3 possesses a significantly distorted six-coordinate pseudooctahedral configuration, in which all six heteroatoms (N4O2) coordinate to the iron center. The catalytic property of complex 3 for alkane oxidation were explored using H2O2, TBHP and mCPBA as oxidants in the presence of excess substrates under mild conditions. When cyclohexane oxidation process was monitored by UV-Vis spectra using H2O2 as oxidant at 0 degrees C, a short-life band appeared at ca 550 nm, which is attributed to the in-situ Fe(III)-OOH species.
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| 6. |
- Liu, Haibin, et al.
(author)
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Asymmetric oxidation of sulfides with hydrogen peroxide catalyzed by a vanadium complex of a new chiral NOO-ligand
- 2009
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In: Catalysis communications. - : Elsevier BV. - 1566-7367 .- 1873-3905. ; 11:4, s. 294-297
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Journal article (peer-reviewed)abstract
- A new chiral NOO-tridentate ligand (8R)-2-(2-hydroxyphenyl)-4-methyl-5,6,7.8-tetrahydro-quinolin-8-ol (1) bearing a rigid tetrahydroquinoline framework was prepared and applied in the vanadium-catalyzed asymmetric oxidation of aryl methyl sulfides with H2O2 as oxidant. Less toxic acetone was found to be the proper solvent for the enantioselective oxidation of sulfides. Under the optimal condition, the asymmetric oxidation of aryl methyl sulfides in acetone catalyzed by VO(acac)(2)/1 at 0 degrees C gives good to high yields (80-95%) of sulfoxides with enantioselectivity up to 77% ee.
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| 8. |
- Sun, Hongfei, et al.
(author)
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Synthesis and structure of a mu-oxo diiron(III) complex with an N-pyridylmethyl-N,N-bis(4-methylbenzimidazol-2-yl)amine ligand and its catalytic property for hydrocarbon oxidation
- 2008
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In: Applied organometallic chemistry. - : Wiley. - 0268-2605 .- 1099-0739. ; 22:10, s. 573-576
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Journal article (peer-reviewed)abstract
- A mu-oxo diiron(III) complex [{Fe(pbba)Cl}(2)(mu-O)]Cl-2 (1, pbba = N-pyridylmethyl-N,N-bis(4-methylbenzimidazol-2-yl)amine) bearing multi-imidazolyl motifs was synthesized and characterized by X-ray crystallography to closely mimic the structural features of methane monooxygenase. As shown by its X-ray crystal structure, complex 1 is a centrosymmetric dimer with an Fe-O-Fe angle of 180 degrees, and pseudo-octahedral around each iron(III) center. The catalytic ability of title compound in the oxidation of alkane and alkene is investigated by employing tert-butylhydroperoxide and m-chloroperbenzoic acid as oxidants under mild conditions. The catalytic oxidation results showed that radical intermediate dominates the oxidation process.
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| 9. |
- Sun, S. G., et al.
(author)
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Studies of a series of novel rhenium(I) bipyridyl dyes for solar cells
- 2005
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In: Chinese Chemical Letters. - 1001-8417 .- 1878-5964. ; 16:5, s. 677-680
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Journal article (peer-reviewed)abstract
- A series of novel rhenium(I) 2,2'-bipyridyl complexes [fac-Re(4,4'-di-COOEt-bpy)-(CO)(3)(Xpy)PF6], where bpy is 2,2'-bipyridine, py is pyridine and X is 3-methyl, 3-hydroxy, or 3-amino, were synthesized, their photophysical and electrochemical properties were studied. The Re(II/I) oxidation potentials decreased as the X group becomes more electron donating from H to 3-methyl, 3-hydroxy, or 3-amino, which might be a very convenient ways for adjusting the electron transfer driving force.
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| 10. |
- Sun, Shiguo, et al.
(author)
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Host-guest chemistry and light driven molecular lock of Ru(bpy)(3)-viologen with cucurbit 7-8 urils
- 2007
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In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 111:47, s. 13357-13363
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Journal article (peer-reviewed)abstract
- Host-guest chemistry and photoinduced electron-transfer processes have been studied in the systems containing Ru(bPy)(3) complex covalently linked to viologen as a guest molecule and cucurbit[n]urils (n = 7, 8) as host molecules in aqueous solution. The Ru(bpy)(3)-viologen complex,[Ru(2,2 '-bipyridine)(2)(4-(4-(1 '-methyl-4,4 '-bipyridinediium-1-yl)butyl)-4 '-methyl-2,2 '-bipyridine)]Cl-4(denoted as RU2+-MV2+, 1) was shown to form stable 1:1 inclusion complexes with cucurbit[7]uril (CB[7]) and cucurbit[8] uril (CB[8]). The binding modes are slightly different with CB[7] and CB[8]. CB[7] preferentially binds to part of the viologen residue in 1 together with the butyl chain, whereas CB[8] preferentially encloses the whole viologen residue. Photoinduced intramolecular electron transfer from the excited-state of the Ru moiety to MV2+ which is inserted into the cavity of the CBs occurred. Long-lived charge-separated states RU3+-MV+center dot, were generated with the lifetimes of 280 ns with CB[7] and 2060 ns with CB[8]. This shows that CBs can slow down the charge recombination within supramolecular systems, and the difference in lifetimes seems to be due to the difference in binding modes. In the presence of a sacrificial electron donor triethanolarnine, light-driven formation of a dimer of MV+center dot inside the CB[8] cavity was observed. This locked molecular dimer can be unlocked by molecular oxygen to give back the original form of the molecular dyad 1 with the MV2+ moiety inserted in the cavity of CB[8]. The processes could be repeated several times and showed nice reversibility.
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