scholarly journals A complex with nitrogen single, double, and triple bonds to the same chromium atom: synthesis, structure, and reactivity

2016 ◽  
Vol 7 (4) ◽  
pp. 2532-2536 ◽  
Author(s):  
Evan P. Beaumier ◽  
Brennan S. Billow ◽  
Amrendra K. Singh ◽  
Shannon M. Biros ◽  
Aaron L. Odom
Keyword(s):  
Chromium Atom ◽  
Metal Center ◽  
Triple Bonds

A complex with single, double and triple bonds between nitrogen and the same metal center has been synthesized, [NCr(NPh)(NPri2)2]−. The complex shows differential activity, with some electrophiles attacking the imido and others the nitrido.

Some Problems in the Oxidative Addition and Binding of an Ethylene to a Transition Metal Center.

1987 ◽  
Vol 6 (4) ◽  
pp. 902-902
Author(s):  
Jerome Silestre ◽  
Maria Calhorda ◽  
Roald Hoffman ◽  
Page Stoutland ◽  
Robert Bergman
Keyword(s):  
Transition Metal ◽  
Oxidative Addition ◽  
Metal Center

The First Coordination of an (α-Diazo)phosphine to a Transition-Metal Center

2003 ◽  
Vol 22 (7) ◽  
pp. 1358-1360 ◽  
Author(s):  
Emmanuelle Despagnet-Ayoub ◽  
Heinz Gornitzka ◽  
John Fawcett ◽  
Philip W. Dyer ◽  
Didier Bourissou ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Center

scholarly journals Molecular Dynamics of Cobalt Protoporphyrin Antagonism of the Cancer Suppressor REV-ERBβ

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3251
Author(s):  
Taufik Muhammad Fakih ◽  
Fransiska Kurniawan ◽  
Muhammad Yusuf ◽  
Mudasir Mudasir ◽  
Daryono Hadi Tjahjono
Keyword(s):  
Binding Site ◽  
Nuclear Receptor ◽  
Target Genes ◽  
Protoporphyrin Ix ◽  
Binding Energies ◽  
Metal Center ◽  
Complex Nature ◽  
Dynamic Simulations ◽  
Subtle Change ◽  
Cobalt Protoporphyrin

Nuclear receptor REV-ERBβ is an overexpressed oncoprotein that has been used as a target for cancer treatment. The metal-complex nature of its ligand, iron protoporphyrin IX (Heme), enables the REV-ERBβ to be used for multiple therapeutic modalities as a photonuclease, a photosensitizer, or a fluorescence imaging agent. The replacement of iron with cobalt as the metal center of protoporphyrin IX changes the ligand from an agonist to an antagonist of REV-ERBβ. The mechanism behind that phenomenon is still unclear, despite the availability of crystal structures of REV-ERBβ in complex with Heme and cobalt protoporphyrin IX (CoPP). This study used molecular dynamic simulations to compare the effects of REV-ERBβ binding to Heme and CoPP, respectively. The initial poses of Heme and CoPP in complex with agonist and antagonist forms of REV-ERBβ were predicted using molecular docking. The binding energies of each ligand were calculated using the MM/PBSA method. The computed binding affinity of Heme to REV-ERBβ was stronger than that of CoPP, in agreement with experimental results. CoPP altered the conformation of the ligand-binding site of REV-ERBβ, disrupting the binding site for nuclear receptor corepressor, which is required for REV-ERBβ to regulate the transcription of downstream target genes. Those results suggest that a subtle change in the metal center of porphyrin can change the behavior of porphyrin in cancer cell signaling. Therefore, modification of porphyrin-based agents for cancer therapy should be conducted carefully to avoid triggering unfavorable effects.

scholarly journals Predicting the new carbon nanocages, fullerynes: a DFT study

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Qasemnazhand ◽  
Farhad Khoeini ◽  
Farah Marsusi
Keyword(s):  
Density Functional Theory ◽  
Lithium Ion Batteries ◽  
Density Functional ◽  
Lithium Ion ◽  
The Other ◽  
Electron Affinities ◽  
Chemical Formula ◽  
Functional Theory ◽  
Triple Bonds ◽  
Structural And Electronic Properties

AbstractIn this study, based on density functional theory, we propose a new branch of pseudo-fullerenes which contain triple bonds with sp hybridization. We call these new nanostructures fullerynes, according to IUPAC. We present four samples with the chemical formula of C4nHn, and the structures derived from fulleranes. We compare the structural and electronic properties of these structures with those of two common fullerenes and fulleranes systems. The calculated electron affinities of the sampled fullerynes are negative, and much smaller than those of fullerenes, so they should be chemically more stable than fullerenes. Although fulleranes also exhibit higher chemical stability than fullerynes, but pentagon or hexagon of the fullerane structures cannot pass ions and molecules. Applications of fullerynes can be included in the storage of ions and gases at the nanoscale. On the other hand, they can also be used as cathode/anode electrodes in lithium-ion batteries.

scholarly journals First total synthesis of the (±)-2-methoxy-6-heptadecynoic acid and related 2-methoxylated analogs as effective inhibitors of the Leishmania topoisomerase IB enzyme

2012 ◽  
Vol 84 (9) ◽  
pp. 1867-1875 ◽  
Author(s):  
Néstor M. Carballeira ◽  
Michelle Cartagena ◽  
Fengyu Li ◽  
Zhongfang Chen ◽  
Christopher F. Prada ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Total Synthesis ◽  
Leishmania Donovani ◽  
Dna Topoisomerase ◽  
Triple Bonds ◽  
Weak Intermolecular Interactions ◽  
Topoisomerase Ib ◽  
Effective Inhibition ◽  
Acetylenic Fatty Acid

The fatty acids (±)-2-methoxy-6Z-heptadecenoic acid, (±)-2-methoxy-6-hepta-decynoic acid, and (±)-2-methoxyheptadecanoic acid were synthesized and their inhibitory activity against the Leishmania DNA topoisomerase IB enzyme (LdTopIB) determined. Both 2-OMe-17:1 fatty acids were synthesized from 4-bromo-1-pentanol, the olefinic fatty acid in 10 steps and in 7 % overall yield, while the acetylenic fatty acid in 7 steps and in 14 % overall yield. The 2-OMe-17:0 acid was prepared in 6 steps and in 42 % yield from 1-hexa-decanol. The 2-OMe-17:1 acids inhibited LdTopIB, with the acetylenic acid displaying an EC50 = 16.6 ± 1.1 μM, but the 2-OMe-17:0 acid did not inhibit LdTopIB. The (±)-2-methoxy-6Z-heptadecenoic acid preferentially inhibited LdTopIB over the human TopIB enzyme. Unsaturation seems to be a prerequisite for effective inhibition, rationalized in terms of weak intermolecular interactions between the active site of LdTopIB and either the double or triple bonds of the fatty acids. Toxicity toward Leishmania donovani promastigotes was also investigated, resulting in the order acetylenic > olefinic > saturated with the (±)-2-methoxy-6-heptadecynoic acid displaying an EC50 = 74.0 ± 17.1 μM. Our results indicate that α-methoxylation decreases the toxicity of C17:1 fatty acids toward L. donovani promastigotes, but improves their selectivity index.

Bimetallic Group 6 Tricarbonyls Triply-Bridged by Bis(phenylthio)alkane Bidentate Ligands

2010 ◽  
Vol 93-94 ◽  
pp. 13-16
Author(s):  
Khalil J. Asali
Keyword(s):  
1H Nmr ◽  
Elemental Analysis ◽  
Thermodynamic Stability ◽  
Chlorinated Hydrocarbons ◽  
Metal Center ◽  
Molar Ratio ◽  
Bidentate Ligands ◽  
Group 6 ◽  
Ft Ir

Reactions of the labile complex (Me3tach)M(CO)3 (Me3tach = 1,3,5-trimethyl-1,3,5-triazacyclohexane; M = W, Mo) with bis(phenylthio)alkanes ( = PhS(CH2)nSPh), (2:3 molar ratio) in CH2Cl2 as solvent (at 35 oC M = W, 0 oC M = Mo) afforded in good yields bimetallic tricarbonyl complexes triply- bridged by bis(phenylthio)alkanes of the type [M(CO)3]2(μ-PhS-(CH2)n-SPh)3 [n = 3 (a), 4 (b), 5 (c), 6 (d); M = W (1), Mo (2)]. These new triply-bridged complexes were characterized by 1H NMR, FT-IR and elemental analysis. Additionally, it has been observed that the thermodynamic stability of some of these new complexes in chlorinated hydrocarbons depends mainly on the nature of the metal center and varies in the order W >> Mo.

Molecular orbital and spectroscopic studies of triple bonds between transition-metal atoms. 2. The d5-d5 Re2Cl4(PR3)4 compounds

1983 ◽  
Vol 105 (9) ◽  
pp. 2606-2611 ◽  
Author(s):  
Bruce E. Bursten ◽  
F. Albert Cotton ◽  
Phillip E. Fanwick ◽  
George G. Stanley ◽  
Richard A. Walton
Keyword(s):  
Transition Metal ◽  
Molecular Orbital ◽  
Spectroscopic Studies ◽  
Triple Bonds ◽  
Metal Atoms ◽  
Transition Metal Atoms

Intramolecular Michael and Anti-Michael Additions to Carbon-Carbon Triple Bonds

Synlett ◽  
1993 ◽  
Vol 1993 (06) ◽  
pp. 369-374 ◽  
Author(s):  
Wolf-Dieter Rudorf ◽  
Ralf Schwarz
Keyword(s):  
Michael Additions ◽  
Triple Bonds
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