86847-79-2Relevant academic research and scientific papers
Preparations, Structures, and Properties of Copper(II) Complexes with a New Tripodal Tetradentate Ligand, N-(2-Pyridylmethyl)bis(6-pivalamido-2-pyridylmethyl)amine, and Reactivities of the Cu(I) Complex with Dioxygen
Harata, Manabu,Hasegawa, Koji,Jitsukawa, Koichiro,Masuda, Hideki,Einaga, Hisahiko
, p. 1031 - 1038 (1998)
Copper complexes of a tripodal tetradentate ligand, N-(2-pyridylmethyl)bis(6-pivalamido-2-pyridylmethyl)amine (Hbppa), have been prepared as a model of metal centers of mononuclear copper enzymes; their structures and properties have been examined together with those having several secondary ligands by electronic absorption, ESR and FAB mass spectral, cyclic voltammetric, and X-ray diffraction methods. The complexes, [Cu(Hbppa)](ClO4)2 and [Cu(Hbppa)(N3)]- ClO4·H2O, were obtained as single crystals, whose crystal structures revealed square-planar and trigonal-bipyramidal geometries, respectively. The electronic absorption and ESR spectra for the CuII(Hbppa)-X systems (X = no, Cl-, Br-, I-, N3-, and CH3COO-) allowed us to conclude that the complexes form several coordination geometries, such as square-planar, square-pyramidal, and trigonal-bipyramidal, depending upon the solvents (MeOH, MeCN). The redox potentials of [Cu(Hbppa)Cl]Cl in MeCN, THF, MeOH, and CH2Cl2 showed quasi-reversible CuI/CuII couples in the range of -0.056 - +0.085 V vs. Ag/AgCl at room temperature. The addition of dioxygen to the Cu(I)-Hbppa, which was prepared from [Cu(MeCN)4]PF6 and Hbppa (1:1) in EtCN at -78°C, resulted in a graduate absorption spectral change with two well-separated absorption maxima at 665 (ε= 162 M-1 cm-1) and 837 nm (ε = 305 M-1 cm-1) and an intense band at 375 nm (ε = 641 M-1 cm-1) as a shoulder. Simultaneous ESR experiments of the same complex solution exhibited a silent spectrum, indicating that the complex is diamagnetic. A similar electronic absorption spectral change was observed in MeOH with absorption peaks at 387 nm (ε = 843 M-1 cm-1), 640 (ε = 183 M-1 cm-1) and 828 (ε = 289 M-1 cm-1), although the ESR spectrum did not continue to be completely silent. Increasing the temperature of the solution up to room temperature demonstrated the formation of [Cu(Hbppa)(OH)]- species, whose X-ray structure was [Cu(Hbppa)(OH)]PF6·H2O. The reaction of the [Cu(Hbppa)]ClO4-sodium benzoylformate system with dioxygen in DMF resulted in production of carbon dioxide and benzoic acid, as analyzed by GC and HPLC.
Detection of Hg2+ ion using highly selective fluorescent chemosensor in real water sample and in-vitro cell study upon breast adenocarcinoma (MCF-7)
Dey, Swapan,Kumar, Ashish,Hira, Sumit Kumar,Manna, Partha Pratim
, p. 382 - 390 (2019)
A novel rhodamine-based chemosensor (R) was designed and synthesised for selective recognition of Hg2+ ion in real water samples collected from different places. The chemosensor was prepared in green condition with high yield. The selectivity of R was examined with various metal ions, among which only Hg2+ was identified selectively with off–on mechanism along with enhancement of fluorescence. Metal ions recognition has been carried out using UV–vis and fluorescence studies taking μM concentration of chemosensor R in HEPES buffer. The detection limit of R was calculated and found to be 4.4?×?10–9?M. Quantum chemical (DFT) calculation was carried out in order to acquire knowledge about the stability of R in presence of Hg2+ ions. Cell viability and fluorescence microscopic experiments showed R as cytocompatible and can be used as a fluorescent probe for detecting Hg2+ in living cells.
Synthesis and Structure of a New Tripodal Polypyridine Copper(II) Complex That Enables to Recognize a Small Molecule
Harata, Manabu,Jitsukawa, Koichiro,Masuda, Hideki,Einaga, Hisahiko
, p. 61 - 62 (1995)
With a view to constructing an artificial metalloenzyme model complex which can recognize and capture a small molecule, a new tripodal ligand, tris(6-pivaloylamino-2-pyridylmethyl)amine, and its mononuclear copper(II) complex has been synthesized, and they were characterized by 1H-NMR and positive-ion FAB mass spectra, cyclic voltammetry and X-ray structure analysis.
Electrocatalytic Hydrogen Production by a Nickel(II) Complex with a Phosphinopyridyl Ligand
Tatematsu, Ryo,Inomata, Tomohiko,Ozawa, Tomohiro,Masuda, Hideki
, p. 5247 - 5250 (2016)
A novel nickel(II) complex [Ni(L)2Cl]Cl with a bidentate phosphinopyridyl ligand 6-((diphenylphosphino)methyl)pyridin-2-amine (L) was synthesized as a metal-complex catalyst for hydrogen production from protons. The ligand can stabilize a low Nioxidation state and has an amine base as a proton transfer site. The X-ray structure analysis revealed a distorted square-pyramidal NiIIcomplex with two bidentate L ligands in a transarrangement in the equatorial plane and a chloride anion at the apex. Electrochemical measurements with the NiII complex in MeCN indicate a higher rate of hydrogen production under weak acid conditions using acetic acid as the proton source. The catalytic current increases with the stepwise addition of protons, and the turnover frequency is 8400s-1 in 0.1 m [NBu4][ClO4]/MeCN in the presence of acetic acid (290equiv) at an overpotential of circa 590mV. A nickel(II) complex [Ni(L)2Cl]Cl (L= 6-((diphenylphosphino)methyl)pyridin-2-amine), having an amine base as a proton-transfer site, was synthesized and used as a hydrogen-production catalyst. Electrochemical measurements with the complex show that a higher rate of H2 production (turnover frequency=8400s-1) can be achieved under weak acid conditions using acetic acid as a proton source.
Photoinduced Trifluoromethylation of Arenes and Heteroarenes Catalyzed by High-Valent Nickel Complexes
Deolka, Shubham,Govindarajan, Ramadoss,Khaskin, Eugene,Fayzullin, Robert R.,Roy, Michael C.,Khusnutdinova, Julia R.
supporting information, p. 24620 - 24629 (2021/10/08)
We describe a series of air-stable NiIII complexes supported by a simple, robust naphthyridine-based ligand. Access to the high-valent oxidation state is enabled by the CF3 ligands on the nickel, while the naphthyridine exhibits either a monodentate or bidentate coordination mode that depends on the oxidation state and sterics, and enables facile aerobic oxidation of NiII to NiIII. These NiIII complexes act as efficient catalysts for photoinduced C(sp2)?H bond trifluoromethylation reactions of (hetero)arenes using versatile synthetic protocols. This blue LED light-mediated catalytic protocol proceeds via a radical pathway and demonstrates potential in the late-stage functionalization of drug analogs.
Cobalt carbonyl coordination compound and preparation method thereof
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Paragraph 0053; 0059; 0060, (2020/07/14)
The invention discloses a cobalt carbonyl coordination compound and a preparation method thereof, wherein the molecular formula of the cobalt carbonyl coordination compound is [Co(bapa)(O2CO)]ClO4.2H2O, and the bapa represents bis(6-amino-2-pyridylmethyl)(2-pyridylmethyl)amine. The preparation method comprises the following steps: mixing [Co(H2O)6](ClO4)2, bapa, NaHCO3 and a H2O/methanol mixed solvent, introducing air, bubbling, stirring, reacting, and carrying out post-treatment to obtain the cobalt carbonyl coordination compound. The cobalt carbonyl coordination compound disclosed by the invention is a brand-new cobalt carbonyl (III) coordination compound with a tripodal ligand, is used as a novel structure model to provide an important research object for research of coordination chemistry, and has extremely high academic value, and the preparation method has the advantages of mild reaction conditions, low energy consumption, high purification efficiency and the like, and has important significance for preparing the cobalt carbonyl coordination compound.
Dioxygen-Derived Nonheme Mononuclear FeIII(OH) Complex and Its Reactivity with Carbon Radicals
Yadav, Vishal,Gordon, Jesse B.,Siegler, Maxime A.,Goldberg, David P.
supporting information, p. 10148 - 10153 (2019/07/05)
A new tetradentate, monoanionic, mixed N/O donor ligand (BNPAPh2O-) with second coordination sphere H-bonding groups has been synthesized for stabilization of a terminal FeIII(OH) complex. The complex FeII(BNPAPh2O)(OTf) (1) reacts with O2 to give a mononuclear terminal FeIII(OH) complex, FeIII(OH)(BNPAPh2O)(OTf) (2), both of which were characterized by X-ray diffraction, electrospray ionization mass spectrometry, UV-vis, 1H and 19F nuclear magnetic resonance, 57Fe M?ssbauer, and electron paramagnetic resonance spectroscopies. Treatment of 2 with carbon radicals (Ar3C·) gives Ar3COH and the FeII complex 1, in direct analogy with the elusive radical "rebound" process proposed for nonheme iron enzymes.
Site-Selective C–H Functionalization of (Hetero)Arenes via Transient, Non-symmetric Iodanes
Fosu, Stacy C.,Hambira, Chido M.,Chen, Andrew D.,Fuchs, James R.,Nagib, David A.
supporting information, p. 417 - 428 (2019/02/14)
Fosu, Hambira, and colleagues describe the direct C–H functionalization of medicinally relevant arenes or heteroarenes. This strategy is enabled by transient generation of reactive, non-symmetric iodanes from anions and PhI(OAc)2. The site-selective incorporation of Cl, Br, OMs, OTs, and OTf to complex molecules, including within medicines and natural products, can be conducted by the operationally simple procedure included herein. A computational model for predicting site selectivity is also included. The discovery of new medicines is a time- and labor-intensive process that frequently requires over a decade to complete. A major bottleneck is the synthesis of drug candidates, wherein each complex molecule must be prepared individually via a multi-step synthesis, frequently requiring a week of effort per molecule for thousands of candidates. As an alternate strategy, direct, post-synthetic functionalization of a lead candidate could enable this diversification in a single operation. In this article, we describe a new method for direct manipulation of drug-like molecules by incorporation of motifs with either known pharmaceutical value (halides) or that permit subsequent conversion (pseudo-halides) to medicinally relevant analogs. This user-friendly strategy is enabled by combining commercial iodine reagents with salts and acids. We expect this simple method for selective, post-synthetic incorporation of molecular diversity will streamline the discovery of new medicines. A strategy for C–H functionalization of arenes and heteroarenes has been developed to allow site-selective incorporation of various anions, including Cl, Br, OMs, OTs, and OTf. This approach is enabled by in situ generation of reactive, non-symmetric iodanes by combining anions and bench-stable PhI(OAc)2. The utility of this mechanism is demonstrated via para-selective chlorination of medicinally relevant arenes, as well as site-selective C–H chlorination of heteroarenes. Spectroscopic, computational, and competition experiments describe the unique nature, reactivity, and selectivity of these transient, unsymmetrical iodanes.
A switch type zinc ion fluorescent probe and its preparation method and application
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Paragraph 0048-0051, (2019/02/02)
The invention provides a open-closed type zinc ion fluorescent probe and a preparation method and an application thereof; the open-closed type zinc ion fluorescent probe has the structure described in the specification. The probe takes a rhodamine dye as
Controlled and Reversible Stepwise Growth of Linear Copper(I) Chains Enabled by Dynamic Ligand Scaffolds
Rivada-Wheelaghan, Orestes,Aristizábal, Sandra L.,López-Serrano, Joaquín,Fayzullin, Robert R.,Khusnutdinova, Julia R.
supporting information, p. 16267 - 16271 (2017/11/29)
Reversible stepwise chain growth in linear CuI assemblies can be achieved by using the dynamic, unsymmetric naphthyridinone-based ligand scaffolds L1 and L2. With the same ligand scaffolds, the length of the linear copper chain can be varied from two to three and four copper atoms, and the nuclearity of the complex is easily controlled by the stepwise addition of a CuI precursor to gradually increase the chain length, or by the reductive removal of Cu atoms to decrease the chain length. This represents a rare example of a stepwise controlled chain growth in extended metal atom chains (EMACs). All complexes are formed with excellent selectivity, and the mutual transformations of the complexes of different nuclearity were found to be fast and reversible. These unusual rearrangements of metal chains of different nuclearities were achieved by a stepwise “sliding” movement of the naphthyridinone bridging fragment along the metal chain.
