20947-95-9Relevant academic research and scientific papers
Enzyme Control Over Ferric Iron Magnetostructural Properties
Bacon, Jeffrey W.,Caravan, Peter,Cleary, Michael B.,Gale, Eric M.,Lewis, Luke C.,Shafaat, Hannah S.,Wang, Huan
supporting information, (2021/12/06)
Fe3+ complexes in aqueous solution can exist as discrete mononuclear species or multinuclear magnetically coupled species. Stimuli-driven change to Fe3+ speciation represents a powerful mechanistic basis for magnetic resonance sensor technology, but ligand design strategies to exert precision control of aqueous Fe3+ magnetostructural properties are entirely underexplored. In pursuit of this objective, we rationally designed a ligand to strongly favor a dinuclear μ-oxo-bridged and antiferromagnetically coupled complex, but which undergoes carboxylesterase mediated transformation to a mononuclear high-spin Fe3+ chelate resulting in substantial T1-relaxivity increase. The data communicated demonstrate proof of concept for a novel and effective strategy to exert biochemical control over aqueous Fe3+ magnetic, structural, and relaxometric properties.
COMPLEX CATALYSTS BASED ON AMINO-PHOSPHINE LIGANDS FOR HYDROGENATION AND DEHYDROGENATION PROCESSES
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Page/Page column 30, (2014/09/29)
The present application discloses novel PWNN and PWNWP metal catalysts for organic chemical syntheses including hydrogenation (reduction) of unsaturated compounds or dehydrogenation of substrates. The range of hydrogenation substrate compounds includes esters, lactones, enals, enones, enolates, oils and fats, resulting in alcohols, enols, diols, and triols as reaction products. The catalysts of current application can be used to catalyze a hydrogenation reaction under solvent free conditions. The present catalysts also allow the hydrogenation to proceed without added base, and it can be used in place of the conventional reduction methods employing hydrides of the main-group elements. Furthermore, the catalysts of the present application can catalyze a dehydrogenation reaction under homogenous and/or acceptorless conditions. As such, the catalysts provided herein can be useful in substantially reducing cost and improving the environmental profile of manufacturing processes for a variety of chemicals.
Design, synthesis, and bioactivity of cyanonitrovinyl neonicotinoids as potential insecticides
Wang, Kewei,Qian, Xuhong,Cui, Jingnan
scheme or table, p. 1117 - 1122 (2012/06/18)
A series of cyanonitrovinyl neonicotinoids were designed and synthesized via five steps in about 35% overall yields. All compounds were structurally characterized by 1H nuclear magnetic resonance (NMR), 13C NMR, infrared (IR), and high-resolution mass spectrometry (HRMS), and single-crystal X-ray diffraction analysis of 2-[1-[(6-chloropyridin-3-yl)methyl] -2-imidazolidinylidene]-2-nitroacetonitrile revealed that the double bond is (E)-configured. The preliminary agriculture bioassay indicated that one compound exhibited moderate insecticidal activity against pea aphid. Springer-Verlag 2010.
One step from nitro to oxime: a convenient preparation of unsaturated oximes by the reduction of the corresponding vinylnitro compounds
Wang, Kewei,Qian, Xuhong,Cui, Jingnan
experimental part, p. 10377 - 10382 (2010/02/27)
A series of novel unsaturated oximes were conveniently prepared from the corresponding vinylnitro compounds by reduction with SnCl2·2H2O. The structures of the oximes were characterized by 1H and 13C NMR, IR and HRMS, and X-ray crystallography analysis of 1-(6-chloro-pyridin-3-ylmethyl)-4,5-dihydro-1H-imidazole-2-carbaldehyde oxime 2a reveals that, the hydroxyl group is arranged in a trans configuration. Some evidences from a brief investigation suggest that these oximes seem to be formed by reduction of the aci form of nitro aliphatic compounds.
Design, synthesis, and evaluation of unsymmetrical difluoro-boron complexes with imidazoline as potential fungicides
Wang, Kewei,Cui, Jingnan,Xie, Lijuan,Qian, Xuhong
experimental part, p. 418 - 424 (2010/08/05)
A series of unsymmetrical difluoroboron (BF2) complexes with pyridine and imidazoline were synthesized by reaction of new chelating ligands (arylmethyl-imidazolidinylidene)-pyridin-2-yl-amine with boron trifluoride diethyl etherate. All the ligands and BF2 complexes were structurally characterized by IR, HRMS, 1H, 13C, 11B, and 19F NMR,indicating the bidentate complexation of imidazoline nitrogen and the pyridine nitrogen to the boron center. Evaluation of agricultural bioactivities showed that some of the BF2 complexes exhibited moderate fungicidal activities, and most of the BF2 complexes exhibited higher activities than the none-BF2 complexed substrates.
Robust and electron-rich cis-palladium(II) complexes with phosphine and carbene ligands as catalytic precursors in Suzuki coupling reactions
Liao, Chuang-Yi,Chan, Kai-Ting,Tu, Cheng-Yi,Chang, Yu-Wei,Hu, Ching-Han,Lee, Hon Man
scheme or table, p. 405 - 417 (2009/09/28)
A new imidazolinium ligand precursor [L2H]Cl (2) was prepared in 86 % yield. Compared with its imidazolium counterpart, [L1H]Cl (1), 2 is very sensitive to moisture and can undergo ring-opening reactions very readily. Palladium complexes with the ring-opened products from imidazolinium salts were isolated and characterized by X-ray crystallography. Theoretical studies confirmed that the imidazolinium salt has a higher propensity for the ring-opening reaction than the imidazolium counterpart. New mixed phosphine/carbene palladium complexes, Cis-[PdCl2(L)(PR3)] (L = L1 and L2; R = Ph. Cy). were successfully prepared. These complexes are highly robust as revealed by variable-temperature NMR spectroscopic studies and thermal gravimetric analysis. The structural and electronic properties of the new complexes on varying the carbene group (imidazol-2-ylidene group (unsaturated carbene) vs. imidazolin-2-ylidene (saturated carbene)) and the phosphine group (PPh3 vs. PCy 3) were studied in detail by X-ray crystallography, X-ray photoelectron spectroscopy, and theoretical calculations. The catalytic study reveals that Cis-[PdCl2(L2)-(PCy3)] is a competent PdII precatalyst for Suzuki coupling reactions, in which unreactive aryl chlorides can be applied as substrates.
RuIII complexes of edta and dtpa polyaminocarboxylate analogues and their use as nitric oxide scavengers
Storr, Tim,Cameron, Beth R.,Gossage, Robert A.,Yee, Helen,Skerlj, Renato T.,Darkes, Marilyn C.,Fricker, Simon P.,Bridger, Gary J.,Davies, Nathan A.,Wilson, Michael T.,Maresca, Kevin P.,Zubieta, Jon
, p. 2685 - 2697 (2007/10/03)
In this study a series of RuIII complexes, chelated by analogues of ethylenediaminetetraacetic acid (edta) and diethylenetriaminepentaacetic acid (dtpa), were produced and tested for NO scavenging ability. Modifications to the edta and dtpa ligand frameworks were made in an effort to alter the reactivity, aqueous stability and pharmacokinetics of the resulting Ru III complexes. The X-ray structure of the nitrosyl complex 38 confirms that the RuIII complex 27 reacts with NO to form a linear {Ru-NO}[6] complex. The nitrosyl complex [C15H 15N4O11Ru] crystallized in the P21/c space group with a = 12.731(3) A, b = 10.894(2) A, c = 14.241 (3) A, β= 107.320(4)°, V = 1885.6(7) A3, and Z = 4. Kinetic studies on the reactions of 14 (k = 2.38 × 106 M -1 s-1) and 27 (k = 2.30 × 105 M -1 s-1) with NO exemplify the difference in chemical properties obtained by ligand framework manipulation. Binding constants of 14 (KB = 5×106 M-1) and 27 (KB = 2 × 105 M-1) with NO were also measured, indicating the tight binding of NO by the RuIII complexes. The activity of the RuIII complexes to scavenge nitric oxide was evaluated using RAW264 murine macrophage cells. Ligand analogues of edta that have a pyridine donor as part of the N,N chelate such as 20 and 24 exhibit similar scavenging activity to the parent compound. Ligand analogues of dtpa that have R groups at the central amine in place of the carboxylic acid such as 31, 34, and 37 are also efficient NO scavengers. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Flexible N,N,N-chelates as supports for iron and cobalt chloride complexes; synthesis, structures, DFT calculations and ethylene oligomerisation studies
Cowdell, Richard,Davies, Christopher J.,Hilton, Stephen J.,Marechal, Jean-Didier,Solan, Gregory A.,Thomas, Owen,Fawcett, John
, p. 3231 - 3240 (2007/10/03)
The aryl-substituted N-picolylethylenediamine and diethylenetriamine ligands, (ArNHCH2CH2){(2-C5H 4N)CH2}NH and (ArNHCH2CH2) 2NH (Ar = 2,6-Me2C6H
Mixed-valence Dinuclear Iron Complexes with a Nonadentate Polypyridine Ligand: High-spin Iron(II)-Low-spin Iron(III)
Maeda, Yonezo,Kawano, Kota,Oniki, Takayuki
, p. 3533 - 3536 (2007/10/03)
Dinuclear iron(II,III) complexes X2 with a nonadentate ligand HL, i.e. 4-methyl-2,6-bisphenol, and X = PF6(-) (1) or BPh4(-) (2) have been prepared.Their Moessbauer spectra consist of two quadrupole doublets due to high-spin iron(II) and low-spin iron(III).The magnetic susceptibilities are consistent with this.Cyclic voltammograms in dried acetonitrile showed a quasi-reversible redox couple with E1 = -0.07 V and an irreversible redox couple with E2 = 0.58 V vs. saturated calomel electrode for 1, corresponding to a comproportionation constant of 1.0E12.No visible or near-infrared bands due to intervalence electron transitions between iron-(II) and -(III) were observed.
Compounds and complexes useful in medical imaging
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, (2008/06/13)
The subject of the present invention is compounds which correspond to the following general formula: STR1 in which R1 and R3 independently of one another represent H, an alkyl, alkenyl, cycloalkyl, aryl, arylalkyl or an alkylaryl group, a heterocycle, or groups which are unsubstituted or substituted, in particular by one or more hydroxyl or alkoxy groups or halogen; n represents an integer from 1 to 5; i in each case takes values from 1 to n for the n successive STR2 links; R2, R4i and R5i independently of one another represent H, an alkyl, alkenyl, aryl, alkoxy, hydroxyalkyl, alkoxyalkyl, amido, acyl or carboxyalkyl group, or a salt, or an alkyl ester of the latter; or R4i and R5i together form an oxo group STR3 R6 and R7 represent H, or R6 and R7 together form an oxo group STR4 x represents a 5- or 6-membered heterocycle which contains at least one nitrogen atom, or, in the event that STR5 where R8 and R9 independently represent H, alkyl, aryl or arylalkyl, and R10 represents H, alkyl, aryl or arylalkyl. The present invention likewise relates to coordination complexes between these ligands and a metal as well as to kits containing these ligands and to reagents which permit the formation of a coordination complex between the ligand and the metals. More particularly, the present invention relates to complexes between these ligands and technetium 99m Tc, which complexes can be used as diagnostic agents for brain imaging, heart imaging and blood imaging.
