935552-37-7Relevant articles and documents
Diiron hexacarbonyl complexes bearing naphthalene-1,8-dithiolate bridge moiety as mimics of the sub-unit of [FeFe]-hydrogenase: Synthesis, characterisation and electrochemical investigations
Qian, Guifen,Zhong, Wei,Wei, Zhenhong,Wang, Hailong,Xiao, Zhiyin,Long, Li,Liu, Xiaoming
, p. 9752 - 9760 (2015)
Eight diiron hexacarbonyl complexes bearing a 1,8-dithionaphthalenyl bridging linkage as mimics of the diiron subunit of [FeFe]-hydrogenase are reported. Reaction of Fe3(CO)12 with naphtha[1,8-cd][1,2]dithiole-n-carbaldehyde (n = 2: 2a or 4: 2b) gave two complexes, [Fe2(μ-S)2R(CO)6] (-SRS- = n-formylnaphthalene-1,8-bis(thiolate), n = 2: 3a, 4: 3b), which were further used as precursors to prepare six other complexes by manipulating the formyl groups. Converting the corresponding formyl group into a hydroxymethyl group (CH2OH) led to complexes 4a and 4b. Their reactions with halobutanoyl chloride formed complexes 5a and 5b (halo group = Cl), and 6a and 6b (halo group = Br), respectively. Among the complexes, 3a, 3b, 4b, 5b, and 6a were crystallographically analysed. Electrochemical investigations into these complexes revealed that the formyl group exerts profound electronic influence on the electrochemistry, and thus catalysis of proton reduction, due to its involvement in the conjugation of the bridging linkage. DFT calculations indicate that the formyl group influences the electrochemistry and catalysis by significantly altering the composition of the LUMOs.
A fluorescent sensor for imaging reversible redox cycles in living cells
Miller, Evan W.,Bian, Shelly X.,Chang, Christopher J.
, p. 3458 - 3459 (2007)
We report the synthesis, properties, and biological applications of Redoxfluor-1 (RF1), a new fluorescent sensor for imaging reversible oxidation-reduction cycles in aqueous solution and in living cells. RF1 is comprised of a fluorescein reporter coupled to a disulfide/dithiol switch. The green fluorescent sensor features a reversible response to multiple oxidation or reduction events, a >50-fold fluorescence dynamic range, and excitation and emission profiles in the visible region to minimize cellular damage and autofluorescence. Confocal microscopy experiments show that RF1 can visualize multiple cycles of oxidation and reduction within living cells, establishing the potential value of this approach for probing dynamic oxidation biology events in natural systems. Copyright
The influence of a peripheral functional group of diiron hexacarbonyl complexes on their electrochemistry and electrocatalytic reduction of proton
Zhong, Wei,Xiao, Zhiyin,Qian, Guifen,Liu, Xiaoming
, p. 779 - 786 (2017)
Three diiron hexacarbonyl complexes (2, 3 and 4) with naphthalene-1,8-bis(thiolate) skeleton as their bridging linkages are reported. For comparison, the protonated form of complex 4 was also prepared (4H+). They bear respectively a functional group on the naphthalene ring at the position 2, i.e. ?CH2OH (2), ?COOH (3), ?CH2N(Et)2 (4) and ?CH2NH+(Et)2 (4H+). Complex 2 was derived from the direct reduction of its precursor bearing aldehyde group (?CHO, 1) by NaBH4 while complexes 3 and 4 were routinely synthesized by reacting Fe3(CO)12 with ligands L2 and L3, respectively, which were derived from ligand L1, naphtho[1,8-cd][1,2]dithiole-3-carbaldehyde. These complexes were fully characterized and complexes 3 and 4 were analyzed using X-ray single crystal diffraction. Electrochemistry of these complexes was also investigated by cyclic voltammetry. The carboxylic acid of complex 3 shows significant influence on the second reduction due to the acid group involving reaction with the reduced species. Both infrared spectral data and the first reduction potentials of the complexes suggest that these functional groups exert hardly electronic influence on the metal center. However, the functional groups which can carry proton (?COOH and ?CH2N+H(Et)2) can ease the kinetics of the catalysis of proton reduction via probably PCET (proton-coupled electron transfer) mechanism. These proton carriers can also improve catalytic efficiency by acting a proton relay during the catalysis as suggested by the linear plots of peak current against acid concentration for the three complexes.
Regioselective deiodination of thyroxine by iodothyronine deiodinase mimics: An unusual mechanistic pathway involving cooperative chalcogen and halogen bonding
Manna, Debasish,Mugesh, Govindasamy
body text, p. 4269 - 4279 (2012/04/10)
Iodothyronine deiodinases (IDs) are mammalian selenoenzymes that catalyze the conversion of thyroxine (T4) to 3,5,3′-triiodothyronine (T3) and 3,3′,5′-triiodothyronine (rT3) by the outer- and inner-ring deiodination pathways, respectively. These enzymes also catalyze further deiodination of T3 and rT3 to produce a variety of di- and monoiodo derivatives. In this paper, the deiodinase activity of a series of peri-substituted naphthalenes having different amino groups is described. These compounds remove iodine selectively from the inner-ring of T4 and T3 to produce rT3 and 3,3′-diiodothyronine (3,3′-T2), respectively. The naphthyl-based compounds having two selenols in the peri-positions exhibit much higher deiodinase activity than those having two thiols or a thiol-selenol pair. Mechanistic investigations reveal that the formation of a halogen bond between the iodine and chalcogen (S or Se) and the peri-interaction between two chalcogen atoms (chalcogen bond) are important for the deiodination reactions. Although the formation of a halogen bond leads to elongation of the C-I bond, the chalcogen bond facilitates the transfer of more electron density to the C-I σ* orbitals, leading to a complete cleavage of the C-I bond. The higher activity of amino-substituted selenium compounds can be ascribed to the deprotonation of thiol/selenol moiety by the amino group, which not only increases the strength of halogen bond but also facilitates the chalcogen-chalcogen interactions.
Deiodination of thyroid hormones by iodothyronine deiodinase mimics: Does an increase in the reactivity alter the regioselectivity?
Manna, Debasish,Mugesh, Govindasamy
supporting information; scheme or table, p. 9980 - 9983 (2011/08/21)
Organoselenium compounds as functional mimics of iodothyronine deiodinase are described. The naphthyl-based compounds having two selenol groups are remarkably efficient in the inner-ring deiodination of thyroxine. The introduction of a basic amino group in close proximity to one of the selenol moieties enhances the deiodination. This study suggests that an increase in the nucleophilic reactivity of the conserved Cys residue at the active site of deiodinases is very important for effective deiodination.
