60067-50-7Relevant academic research and scientific papers
Cross-Linked Artificial Enzyme Crystals as Heterogeneous Catalysts for Oxidation Reactions
Lopez, Sarah,Rondot, Laurianne,Leprêtre, Chloé,Marchi-Delapierre, Caroline,Ménage, Stéphane,Cavazza, Christine
supporting information, p. 17994 - 18002 (2017/12/26)
Designing systems that merge the advantages of heterogeneous catalysis, enzymology, and molecular catalysis represents the next major goal for sustainable chemistry. Cross-linked enzyme crystals display most of these essential assets (well-designed mesoporous support, protein selectivity, and molecular recognition of substrates). Nevertheless, a lack of reaction diversity, particularly in the field of oxidation, remains a constraint for their increased use in the field. Here, thanks to the design of cross-linked artificial nonheme iron oxygenase crystals, we filled this gap by developing biobased heterogeneous catalysts capable of oxidizing carbon-carbon double bonds. First, reductive O2 activation induces selective oxidative cleavage, revealing the indestructible character of the solid catalyst (at least 30 000 turnover numbers without any loss of activity). Second, the use of 2-electron oxidants allows selective and high-efficiency hydroxychlorination with thousands of turnover numbers. This new technology by far outperforms catalysis using the inorganic complexes alone, or even the artificial enzymes in solution. The combination of easy catalyst synthesis, the improvement of "omic" technologies, and automation of protein crystallization makes this strategy a real opportunity for the future of (bio)catalysis.
MANGANESE-BASED MAGNETIC RESONANCE CONTRAST AGENTS
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Paragraph 00133, (2014/07/22)
Manganese coordination complexes with utility as magnetic resonance probes and as biological reductant sensors are disclosed. In one embodiment, ligands can stabilize both the Mn2+ and Mn3+ oxidation states. In the presence of a reductant such as glutathione, low relaxivity MnIII-HBET is rapidly converted to high relaxivity MnII-HBET with a 3-fold increase in relaxivity, and concomitant increase in magnetic resonance signal. In another embodiment, ligands were designed to chelate Mn(ll) in a thermodynamically stable and kinetically inert fashion while allowing for direct interaction of Mn(ll) with water. In yet another embodiment, high molecular weight multimers containing six Mn(ll) chelators were prepared. The high molecular weight results in slower tumbling of the molecules in solution and can strongly enhance the Mn(ll) relaxivity.
Redox-activated manganese-based MR contrast agent
Loving, Galen S.,Mukherjee, Shreya,Caravan, Peter
supporting information, p. 4620 - 4623 (2013/05/08)
Here we report a simple Mn coordination complex with utility as a redox-sensitive MR probe. The HBET ligand stabilizes both the Mn2+ and Mn3+ oxidation states. In the presence of glutathione (GSH), low relaxivity MnIII-HBET is converted to high relaxivity Mn II-HBET with a 3-fold increase in relaxivity, and concomitant increase in MR signal. Alternately, hydrogen peroxide can convert Mn II-HBET to MnIII-HBET with a reduction in MR signal.
Highly selective binding of nitric oxide by CoIII and Fe III complexes
Zhang, Zizheng,Suwabe, Tatsuya,Ishikawa, Mai,Funahashi, Yasuhiro,Inomata, Tomohiko,Ozawa, Tomohiro,Masuda, Hideki
, p. 4470 - 4478 (2013/04/24)
In order to construct compounds with highly selective binding activity for NO, two CoIII and two FeIII complexes with square-planar N2O2-type donor sets, N-[2-(2-hydroxybenzylamino)ethyl]-2- hydroxybenzamide (H3L1) and 1,2-bis(2-hydroxybenzoylamino)ethane (H4L2), [CoIII(L1)] (1), Na[CoIII(L2)] (2), [FeIII(L1)] (3), and (PPh4)[FeIII(L2)] (4), were designed and synthesized. These compounds were characterized by electronic absorption, FT-IR, 1H-NMR spectroscopies, ESI-mass spectrometry, and elemental analyses. The redox potentials of the CoIII and Fe III complexes with L1, 1 and 3, have quasi-reversible waves at -0.51 and -0.49 V, respectively, and those with L2, 2 and 4, afforded reversible and irreversible waves at -0.96 and -1.04 V, respectively. Interestingly, all complexes quickly react with NO under an Ar atmosphere to form nitrosyl complexes, as monitored by UV-vis spectroscopy. The formation of nitrosyl complexes was confirmed by the appearance of the N-O stretching vibration at about 1650 cm-1; 1649 for 1, 1651 for 2, 1648 for 3, and 1650 cm -1 for 4. The reactivity of each of these complexes with other small molecules such as NO2-, NO3-, CO, and O2 was also studied. None of the complexes react with CO and O2. CoIII complexes 1 and 2 react with NO2 -, while FeIII complexes, 3 and 4, do not react with small amounts of NO2-. Complex 3 reacts with NO 2- at concentrations above 100 equiv. of NO 2-. We succeeded in preparing complexes with highly selective reactivity for NO. The Royal Society of Chemistry 2013.
A convenient synthesis of nickel(II) and cobalt(II) complexes of unsymmetrical salen-type ligands and their application as catalysts for the oxidation of 2,6-dimethylphenol and 1,5-dihydroxynaphthalene by molecular oxygen
Adam, Waldemar,Saha-Moeller, Chantu R.,Ganeshpure, Pralhad A.
, p. 56 - 62 (2007/10/03)
Salen-type ligands 1-4 have been synthesized in high yields, from which the nickel(II) complexes 9-11 and the cobalt(II) complexes 12 and 13 have been prepared and characterized. The complexes have been assessed for their ability to activate molecular oxygen in the catalytic oxidation of phenols, namely, 2,6-dimethylphenol and 1,5-dihydroxynaphthalene. The nickel complexes 9-11 are inactive in the oxidation of the phenols but the cobalt complexes 12 and 13 show high catalytic activity.
High affinity chelates containing isothiocyanate groups, useful for coupling with peptides and proteins
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, (2008/06/13)
The ligands HBED-SCN, HBPD-SCN, and HTDD-SCN are provided which have enhanced ease of reaction with peptides or proteins and which are suitable for chelating with radioisoptopes, especially Indium-III and Gallium-67.
