Reaction mechanism of hydrogen evolution catalysed by Co and Fe complexes containing a tetra-dentate phosphine ligand – a DFT study

2017 ◽  
Vol 19 (48) ◽  
pp. 32589-32596 ◽  
Author(s):  
Ya-Qiong Zhang ◽  
Rong-Zhen Liao
Keyword(s):  
Reaction Mechanism ◽  
Hydrogen Evolution ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Phosphine Ligand ◽  
Dft Study ◽  
Proton Reduction ◽  
Fe Complexes

The mechanism of proton reduction by mononuclear Co and Fe complexes has been elucidated by density functional calculations.

Sind Metalloprotonencryptanden möglich? – DFT-Studie zur Protonenaffinität von [2.2.2]-analogen Metallocryptanden / Can Metallocryptands act as Proton Cages? – DFT Study of Proton Affinity in [2.2.2]-analogousMetallocryptands Sind Metalloprotonencryptanden m¨oglich? – DFT-Studie zur Protonenaffinit¨at von [2.2.2]-analogen Metallocryptanden

2010 ◽  
Vol 65 (3) ◽  
pp. 231-s261 ◽  
Author(s):  
Ralph Puchta ◽  
Andreas Scheurer
Keyword(s):  
Coordination Chemistry ◽  
Gas Phase ◽  
Proton Affinity ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Dft Study ◽  
Proton Sponges

Based on density functional calculations (RB3LYP/LANL2DZp) the bicyclic metallocryptand [Pd3(L2)2] [(L2)3−: 1,1´ ,1´´-nitrilotris(5,5-dimethylhexane-2,4-dione trianion)] shows the same high gas-phase basicity (−257.1 kcal mol−1) as Lehn’s [2.2.2] cryptand (−254.4 kcal mol−1). This illustrates that the concept of metallotopomers adopted by Saalfrank et al. can be applied to design proton sponges as well as proton cryptands by metallosupramolecular coordination chemistry. The slightly higher gas-phase proton affinity of [Pd3(L2)2] compared to [2.2.2] can be attributed to the smaller cavity in the metallotopomer.

What Silicon Nanocluster is Most Likely Formed in Etching Experiments? Theoretical DFT Study

2008 ◽  
Vol 8 (7) ◽  
pp. 3478-3482
Author(s):  
Nurbosyn U. Zhanpeisov ◽  
Hiroshi Fukumura
Keyword(s):  
Absorption Spectra ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Electrochemical Etching ◽  
Time Dependent ◽  
Cluster Models ◽  
Dft Study ◽  
Basis Sets ◽  
Self Healing ◽  
Tddft Calculations

Density functional calculations at the B3LYP/6-31G* level were performed for Si nanoclusters of ca.1 nm in size. The structural, energetic, electronic as well as the estimated absorption spectra by the time-dependent DFT (TDDFT) calculations using varied functionals and basis sets for the representative cluster models are all in favor of the formation of most probable Si35H36 nanocluster in recent electrochemical etching experiments. The nanostructure has a complete H-termination at the borderline regions and lacks from the presence of any defects like surface Si—Si dimer units formed via self-healing of dangling Si—Si bonds or from any relatively short H…H contacts.

Adsorption and decarbonylation of furfural over H-ZSM-5 zeolite: a DFT study

RSC Advances ◽  
2016 ◽  
Vol 6 (107) ◽  
pp. 105888-105894 ◽  
Author(s):  
Patipan Charoenwiangnuea ◽  
Thana Maihom ◽  
Pipat Kongpracha ◽  
Jakkapan Sirijaraensre ◽  
Jumras Limtrakul
Keyword(s):  
Density Functional Calculations ◽  
Density Functional ◽  
Dft Study ◽  
Zeolite A

The biomass-derived furfural adsorption and decarbonylation to furan over H-ZSM-5 (see picture) have been unraveled by means of density functional calculations with the M06-2X functional.

Density Functional Calculations on Class III Ribonucleotide Reductase:  Substrate Reaction Mechanism with Two Formates

2004 ◽  
Vol 108 (6) ◽  
pp. 2056-2065 ◽  
Author(s):  
Kyung-Bin Cho ◽  
Vladimir Pelmenschikov ◽  
Astrid Gräslund ◽  
Per E. M. Siegbahn
Keyword(s):  
Reaction Mechanism ◽  
Ribonucleotide Reductase ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Class Iii

Mechanisms for CO oxidation on Fe(iii)–OH–Pt interface: a DFT study

2014 ◽  
Vol 176 ◽  
pp. 381-392 ◽  
Author(s):  
Yun Zhao ◽  
Guangxu Chen ◽  
Nanfeng Zheng ◽  
Gang Fu
Keyword(s):  
Co Oxidation ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Structural Models ◽  
Pt Nanoparticles ◽  
Structure Sensitivity ◽  
Catalytic Cycle ◽  
Dft Study ◽  
Bond Strengths ◽  
Catalytic Cycles

The full catalytic cycle that involves the oxidation of two CO molecules is investigated here by using periodic density functional calculations. To simulate the nature of Fe(OH)x/Pt nanoparticles, three possible structural models, i.e., Fe(OH)x/Pt(111), Fe(OH)x/Pt(332) and Fe(OH)x/Pt(322), are built. We demonstrate that Fe(iii)–OH–Pt stepped sites readily react with CO adsorbed nearby to directly yield CO2 and simultaneously produce coordinatively unsaturated iron sites for O2 activation. By contrast, the created interfacial vacancy on Fe(OH)x/Pt(111) prefers to adsorb CO rather than O2, thus inhabiting the catalytic cycles of CO oxidation. We suggest that such structure sensitivity can be understood in terms of the bond strengths of Fe(iii)–OH.

scholarly journals Direct Deoxydehydration of Cyclic Trans-Diol Substrates: An Experimental and Computational Study of the Reaction Mechanism of vanadium(V)-Based Catalysis

2020 ◽  
Author(s):  
Ebru Aksanoglu ◽  
Yee Hwee Lim ◽  
Richard Bryce
Keyword(s):  
Reaction Mechanism ◽  
Triplet State ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Computational Study ◽  
Cost Effective ◽  
Renewable Biomass ◽  
Light Dependence ◽  
Biomass Resources

<p>The deoxydehydration of carbohydrates represents a key target to leverage renewable biomass resources chemically. Using a vanadium(V)-based catalyst, we demonstrate that it is possible to directly deoxydehydrate <i>trans</i>-cyclic diol substrates. Accompanying mechanistic characterisation of this process by density functional calculations points to an energetically tractable route for deoxydehydration of cyclic <i>trans</i>-diol substrates involving stepwise cleavage of the diol C-O bonds <i>via</i> the triplet state; experimentally, this is supported by light dependence of the reaction. Calculations also indicate that cyclic <i>cis</i>-diols and a linear diol substrate can additionally proceed by a concerted singlet DODH mechanism. This work potentially opens a new and cost-effective way to efficiently convert carbohydrates of <i>trans</i>-diol stereochemistry into alkenes. </p>

scholarly journals Direct Deoxydehydration of Cyclic Trans-Diol Substrates: An Experimental and Computational Study of the Reaction Mechanism of vanadium(V)-Based Catalysis

2020 ◽  
Author(s):  
Ebru Aksanoglu ◽  
Yee Hwee Lim ◽  
Richard Bryce
Keyword(s):  
Reaction Mechanism ◽  
Triplet State ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Computational Study ◽  
Cost Effective ◽  
Renewable Biomass ◽  
Light Dependence ◽  
Biomass Resources

<p>The deoxydehydration of carbohydrates represents a key target to leverage renewable biomass resources chemically. Using a vanadium(V)-based catalyst, we demonstrate that it is possible to directly deoxydehydrate <i>trans</i>-cyclic diol substrates. Accompanying mechanistic characterisation of this process by density functional calculations points to an energetically tractable route for deoxydehydration of cyclic <i>trans</i>-diol substrates involving stepwise cleavage of the diol C-O bonds <i>via</i> the triplet state; experimentally, this is supported by light dependence of the reaction. Calculations also indicate that cyclic <i>cis</i>-diols and a linear diol substrate can additionally proceed by a concerted singlet DODH mechanism. This work potentially opens a new and cost-effective way to efficiently convert carbohydrates of <i>trans</i>-diol stereochemistry into alkenes. </p>

DFT STUDY OF SOME TRIVALENT d- AND f-BLOCK METAL ION COMPLEXES OF ALLOXAN

2013 ◽  
Vol 12 (06) ◽  
pp. 1350052
Author(s):  
RITA KAKKAR ◽  
MAMTA BHANDARI ◽  
RITU GABA
Keyword(s):  
Density Functional Calculations ◽  
Metal Ion ◽  
Density Functional ◽  
Vibrational Frequencies ◽  
Dft Study ◽  
Bidentate Ligands ◽  
Metal Ion Complexes ◽  
Alloxan Monohydrate ◽  
Trigonal Prismatic

Density functional calculations have been employed to elucidate the structures of some six coordinated complexes of alloxan monohydrate with some d- and f-block metals. Alloxan monohydrate may exist in the mono-ionized or di-ionized form in its complexes, and both states were investigated. It is found that when the metal ion is coordinated to three bidentate ligands, the structures are nearly trigonal prismatic, but replacement of a bidendate ligand by two monovalent ligands changes the geometry to deformed octahedral. The metal-alloxanate bonding is largely ionic for the lanthanoids. The calculated vibrational frequencies are in agreement with the experimentally determined ones.

Sign in / Sign up

Export Citation Format

Share Document