[(η5-C5Me5)Ru]+ fragments ligated to polyaromatic hydrocarbons: an experimental and computational approach to pathways for haptotropic migration

2015 ◽  
Vol 44 (1) ◽  
pp. 316-329 ◽  
Author(s):  
Matias Rioja ◽  
Paul Hamon ◽  
Thierry Roisnel ◽  
Sourisak Sinbandhit ◽  
Mauricio Fuentealba ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Polyaromatic Hydrocarbons ◽  
Activation Energies ◽  
Computational Approach ◽  
High Activation ◽  
Thermally Induced

DFT calculations indicated rather high activation energies for the thermally induced intramolecular inter-ring haptotropic migration of the [(η5-C5Me5)Ru+] moiety.

Reversible Oxidative-Addition and Reductive-Elimination of Thiophene from a Titanium Complex and Its Thermally-Induced Hydrodesulfurization Chemistry

2019 ◽  
Author(s):  
Alejandra Gomez-Torres ◽  
J. Rolando Aguilar-Calderón ◽  
Carlos Saucedo ◽  
Aldo Jordan ◽  
Alejandro J. Metta-Magaña ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Ring Opening ◽  
Thiophene Ring ◽  
Oxidative Addition ◽  
Reductive Elimination ◽  
Thermally Induced ◽  
Titanium Complex

<p>The masked Ti(II) synthon (<sup>Ket</sup>guan)(<i>η</i><sup>6</sup>-Im<sup>Dipp</sup>N)Ti (<b>1</b>) oxidatively adds across thiophene to give ring-opened (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti[<i>κ</i><sup>2</sup>-<i>S</i>(CH)<sub>3</sub><i>C</i>H] (<b>2</b>). Complex <b>2</b> is photosensitive, and upon exposure to light, reductively eliminates thiophene to regenerate <b>1</b> – a rare example of early-metal mediated oxidative-addition/reductive-elimination chemistry. DFT calculations indicate strong titanium π-backdonation to the thiophene π*-orbitals leads to the observed thiophene ring opening across titanium, while a proposed photoinduced LMCT promotes the reverse thiophene elimination from <b>2</b>. Finally, pressurizing solutions of <b>2 </b>with H<sub>2</sub> (150 psi) at 80 °C leads to the hydrodesulfurization of thiophene to give the Ti(IV) sulfide (<sup>Ket</sup>guan)(Im<sup>Dipp</sup>N)Ti(S) (<b>3</b>) and butane. </p>

Thermally induced nucleation. I. A new way to obtain activation energies for unimolecular reactions

1983 ◽  
Vol 79 (6) ◽  
pp. 2763-2770 ◽  
Author(s):  
Joseph L. Katz ◽  
Joseph G. Ruggiero ◽  
Richard Partch ◽  
Dale Warren ◽  
F. H. Ebetino
Keyword(s):  
Activation Energies ◽  
Unimolecular Reactions ◽  
Thermally Induced

scholarly journals The State of Water in the Isolated Toad Bladder in the Presence and Absence of Vasopressin

1962 ◽  
Vol 45 (5) ◽  
pp. 933-948 ◽  
Author(s):  
Richard M. Hays ◽  
Alexander Leaf
Keyword(s):  
Activation Energy ◽  
Activation Energies ◽  
Bulk Water ◽  
Permeability Barrier ◽  
High Activation ◽  
State Of Water ◽  
Activation Energy For Diffusion ◽  
Presence And Absence ◽  
Rate Limiting ◽  
Resistance To Penetration

An attempt has been made to assess the validity of applying the frictional and viscous coefficients of bulk water to the movement of water and solutes through the urinary bladder of the toad. The temperature dependence of diffusion of THO, C14-urea, C14-thiourea, and net water transfer across the bladder was determined in the presence and absence of vasopressin. The activation energy for diffusion of THO was 9.8 kcal per mole in the absence of vasopressin and 4.1 kcal per mole with the hormone present. Activation energies simultaneously determined following vasopressin for diffusion and net transfers of water were similar, and in the same range as known activation energies for diffusion and viscous flow in water. Urea had activation energies for diffusion of 4.1 and 3.9 kcal per mole in the absence and presence of vasopressin, respectively. Thiourea had a high activation energy for diffusion of 6.3 kcal per mole, which was unchanged, 6.6 kcal per mole, following hormone. These findings suggest that in its rate-limiting permeability barrier, water is present in a structured state, offering a high resistance to penetration by water. Vasopressin enlarges the aqueous channels so that the core of water they contain possesses the physical properties of ordinary bulk water. Urea penetrates the tissue via these aqueous channels while thiourea is limited by some other permeability barrier.

Effects of high activation energies on acoustic timescale detonation initiation

2012 ◽  
Vol 16 (4) ◽  
pp. 650-678 ◽  
Author(s):  
J. D. Regele ◽  
D. R. Kassoy ◽  
O. V. Vasilyev
Keyword(s):  
Activation Energies ◽  
Detonation Initiation ◽  
High Activation

2,5-Bridged 1-Carba-arachno-pentaborane(10) Derivatives – Intermediates on the Way to Pentaalkyl-1,5-dicarba-closo-pentaboranes(5)

2015 ◽  
Vol 70 (10) ◽  
pp. 741-745 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Hans-Joerg Schanz
Keyword(s):  
Nmr Spectroscopy ◽  
Low Temperature ◽  
Thermal Degradation ◽  
Dft Calculations ◽  
Large Excess ◽  
Thermally Induced ◽  
Independent Synthesis ◽  
Induced Decomposition ◽  
C Nmr

AbstractStimulated by a report from (R. Köster, G. Benedikt, M. A. Grassberger, Liebigs Ann. Chem. 1968, 719, 187.) on a carbaborane, for which the structure of 2,3,4,5,-tetraethlyl-1-methyl-2,5-μ-(ethyl-1′,1′-diyl)-1-carba-arachno-pentaborane(10) 1 was proposed, an independent synthesis was developed. Diethyl(ethynyl)borane was generated in situ in the presence of a large excess of “Et2B–H” (hydride bath) by ethynyl/H exchange, using ethynyl(trioctyl)tin to react in a mixture with diethyl(vinyl)borane at low temperature. Hydroboration and Et2B–H-catalysed condensation afforded 1, as shown by 11B, 13C NMR spectroscopy and DFT calculations. Thermal degradation of 1 gave 2,3,4-triethyl-1,5-dimethyl-1,5-dicarba-closo-pentaborane(5), whereas the pentaethyl-1,5-dicarba-closo-pentaborane(5) resulted from thermally induced decomposition of other suitably substituted arachno carbaboranes.

10-Membered Azaenediyne Fused to a Benzothiophene through the Nicholas Macrocyclization: Synthesis and DNA Cleavage Ability

Synlett ◽  
2018 ◽  
Vol 30 (02) ◽  
pp. 161-166 ◽  
Author(s):  
Irina Balova ◽  
Natalia Danilkina ◽  
Andrey Rumyantsev ◽  
Anna Lyapunova ◽  
Alexander D’yachenko ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Dna Cleavage ◽  
Functional Group ◽  
Analysis Data ◽  
Activation Energies ◽  
Efficient Technique ◽  
Bergman Cyclization ◽  
Dsc Analysis ◽  
Cleavage Assay ◽  
Pbr322 Plasmid

The Nicholas-type macrocyclization through NH-tosyl functional group has been found to be an efficient technique for the synthesis of a 10-membered azaenediyne system annulated with a benzothiophene. To compare the activity of azaenediyne synthesized with similar oxa- and carbocyclic enediynes the Bergman cyclization activation energies and the ability of enediynes to cleave DNA (pBR322 plasmid) were investigated. The order of reactivity predicted by DFT calculations (N-enediyne < C-enediyne < O-enediyne) was confirmed by DSC analysis data. Surprisingly azaenediyne was found to be more active in the DNA cleavage assay than the C-analogue.

Oxidative [4+2] Annulation of 1-Naphthols with Alkynes Accelerated by an Electron-Deficient Rhodium(III) Catalysts

2022 ◽  
Author(s):  
Antônio Junio Araujo Dias ◽  
Hiroto Takahashi ◽  
Juntaro Nogami ◽  
Yuki Nagashima ◽  
Ken Tanaka
Keyword(s):  
Dft Calculations ◽  
Activation Energies ◽  
High Efficacy ◽  
Mild Conditions ◽  
Internal Alkynes ◽  
Lower Activation

The 1,3-diethoxycarbonyl-2,4,5-trimethylcyclopentadienyl (CpE) rhodium(III) complex displayed high efficacy in the catalytic oxidative annulation of 1-naphthols with internal alkynes under mild conditions. DFT calculations revealed that lower activation energies for the...

Overcrowded aminophospanitrenes: a case study

2017 ◽  
Vol 72 (11) ◽  
pp. 865-871
Author(s):  
Jürgen Tirrée ◽  
Alexander V. Ruban ◽  
Martin Nieger ◽  
Claudia Li ◽  
László Nyulászi ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Ring Opening ◽  
Ring System ◽  
Thermally Induced ◽  
Induced Decomposition

AbstractIn a search for stable phosphinonitrenes generated by thermally induced decomposition of the azidophosphines 8a, b, different cyclodiphosp(V)azene products were generated. While in the case of 8a the expected phosphinonitrene dimer 10 could be obtained, from 8b, which has the sterically more demanding TMP substituents, product 11, was obtained and characterized. DFT calculations have revealed that the primarily formed phosphinonitrene 9b is unstable against loss of TMP˙, and the resulting radical dimerizes to the biradicaloid 1,3-diaza-2,4-diphosphetane-2,4-diyl 13. Compound 13 then dimerizes after ring opening, yielding in the ring system, which provides the final product upon reaction with the starting azidophosphine.

Controlling electronic effects and intermolecular packing in contorted polyaromatic hydrocarbons (c-PAHs): towards high mobility field effect transistors

2016 ◽  
Vol 18 (22) ◽  
pp. 14886-14893 ◽  
Author(s):  
Kalishankar Bhattacharyya ◽  
Titas Kumar Mukhopadhyay ◽  
Ayan Datta
Keyword(s):  
Dft Calculations ◽  
Field Effect ◽  
Field Effect Transistors ◽  
Polyaromatic Hydrocarbons ◽  
High Mobility ◽  
Md Simulations ◽  
Electronic Effects

Classical MD simulations followed by DFT calculations for computationally screened contorted polyaromatic hydrocarbons reveal encouraging OFET potential.

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