Operando Infrared Spectroscopic and Quantum-chemical Studies on Iridium-catalyzed Hydroformylation

2012 ◽  
Vol 67 (10) ◽  
pp. 1061-1069 ◽  
Author(s):  
Dieter Hess ◽  
Bernd Hannebauer ◽  
Matthias Königa ◽  
Matthias Reckers ◽  
Stefan Buchholz ◽  
...  
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Functional Theory ◽  
Density Functional Theory Level ◽  
Iridium Catalyst ◽  
The Density Functional Theory ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Similarities And Differences ◽  
Activity Enhancement

Hydroformylation of 1-butene using a triphenylphosphine-modified iridium catalyst was investigated by operando infrared spectroscopy. The spectra were interpreted by comparison with quantumchemically calculated vibrational spectra at the density functional theory level. The processes during activation of the catalyst and hydroformylation were investigated in detail, and the results are discussed. The recently discovered phenomenon of activity enhancement in iridium-catalyzed hydroformylation by a preceding activation step, in which the reaction mixture is treated with synthesis gas containing an excess of carbon monoxide under pressure, could be correlated with the appearance of a complex HIr(PPh3)(CO)3. The similarities and differences between iridium- and rhodium-catalyzed hydroformylation are discussed.

scholarly journals Vibrational Analysis of “Dimethylbipyridinylzinc (0) [C12H14N2Zn]”: A DFT Approach

2019 ◽  
Vol 11 (01) ◽  
pp. 17-24
Author(s):  
Tanveer Hasan ◽  
P. K. Singh ◽  
S. H. Mehdi
Keyword(s):  
Title Compound ◽  
Quantum Chemical ◽  
Density Functional ◽  
Vibrational Analysis ◽  
Dft Method ◽  
Functional Theory ◽  
Electronic Parameters ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Equilibrium Geometries

Theoretical quantum chemical studies and spectroscopic investigations on “Dimethylbipyridinylzinc (0) C12H14N2Zn” have been carried out. The quantum chemical density functional theory (DFT) method at B3LYP/3-21G level is used to obtain the equilibrium geometries. We have also performed vibrational analysis of the title compound at their equilibrium geometries and established the complete assignments of the significant vibrational modes. The NLO behaviour of the title compound is described by electric parameters like dipole moment, polarizability and first hyperpolarizability. Besides it the thermodynamical and electronic parameters are also calculated to get a better insight of the molecule under study.

Elucidating the structures and cooperative binding mechanism of cesium salts to the multitopic ion-pair receptor through density functional theory calculations

2015 ◽  
Vol 44 (35) ◽  
pp. 15450-15462 ◽  
Author(s):  
Biswajit Sadhu ◽  
Mahesh Sundararajan ◽  
Gunasekaran Velmurugan ◽  
Ponnambalam Venuvanalingam
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Ion Pair ◽  
Cooperative Binding ◽  
Binding Mechanism ◽  
Functional Theory ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Cesium Salts

Quantum chemical studies predict the binding of Cesium salts to multitopic ion-pair receptor is through cooperative mechanism.

Quantum Chemical Studies for Some Thiazolidinone Derivatives Using Density Functional Theory

2015 ◽  
Vol 21 (9) ◽  
pp. 2717-2726
Author(s):  
Md. Shahzad Khan ◽  
Md. Mushtaque ◽  
Mohd. Shahid Khan ◽  
Anurag Srivastava ◽  
Kakul Husain
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemical ◽  
Density Functional ◽  
Functional Theory ◽  
Chemical Studies ◽  
Quantum Chemical Studies

scholarly journals Molecular bending as a vital step toward transforming planar PAHs to fullerenes and tubular structures

2020 ◽  
Vol 644 ◽  
pp. A146
Author(s):  
Tao Chen ◽  
Yang Wang
Keyword(s):  
Density Functional ◽  
Intermolecular Forces ◽  
Molecular Structures ◽  
Intrinsic Reaction Coordinate ◽  
Functional Theory ◽  
B3lyp Method ◽  
Polycyclic Aromatic ◽  
Chemical Studies ◽  
Quantum Chemical Studies ◽  
Hybrid Density Functional

Context. Polycyclic aromatic hydrocarbons (PAHs) and fullerenes are the largest molecules found in the interstellar medium (ISM). They are abundant and widespread in various astronomical environments. However, the detailed connection between these two species is unknown; in particular, no quantum chemical studies have been performed. Aims. In this work, we investigate a vital step in transforming planar PAHs to fullerenes, that is, the tubulation processes of PAHs. Methods. We used density functional theory for this study. The molecular structures and vibrational frequencies were calculated using the hybrid density functional B3LYP method. To better describe intermolecular forces, we considered Grimme’s dispersion correction in the calculations for this work. Intrinsic reaction coordinate calculations were also performed to confirm that the transition state structures are connected to their corresponding local potential energy surface minima. Results. As expected, we find that it is easier to bend a molecule as it gets longer, whereas it is harder to bend the molecule if it gets “wider” (i.e., with more rows of benzene rings). The change of multiplicity slightly alters the bending energies, while (a complete) dehydrogenation alleviates the bending barrier significantly and facilitates the formation of pentagons, which may act as an indispensable step in the formation of fullerenes in the ISM.

Concerted and Diradical Stepwise Mechanisms in the Diels-Alder Reactions of Phosphinine and Phosphinine Sulfide: A DFT Investigation

2008 ◽  
Vol 63 (3) ◽  
pp. 321-330 ◽  
Author(s):  
Raj K. Bansal ◽  
Neelima Gupta ◽  
Surendra K. Kumawat
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Diels Alder ◽  
Dimethyl Acetylenedicarboxylate ◽  
Functional Theory ◽  
Concerted Mechanism ◽  
Density Functional Theory Level ◽  
The Density Functional Theory

Computations of the concerted and diradical stepwise mechanisms of the Diels-Alder (DA) reactions on the >C=P− functionality of phosphinine and phosphinine sulfide with 1,3-butadiene at the density functional theory level B3LYP/6-311++G**//B3LYP/6-31G** give the values of energy of concert as 10.7 and 2.6 kcal mol−1, respectively. Similarly, the DA reaction of dimethyl acetylenedicarboxylate (DMAD) with the −CH=CH−CH=P− moiety of phosphinine or its sulfide has been investigated theoretically at the same level of theory. The results reveal that in the DA reaction of phosphinine, the role of sulfur is to oxidize phosphorus to generate a phosphinine sulfide intermediate, which subsequently undergoes DA reaction with 2,3-dimethylbutadiene or DMAD by a concerted mechanism to afford the respective cycloadducts.

scholarly journals Copper (IV) Stabilization in Macrocyclic Complexes with 3,7,11,15-Tetraazaporphine, Its Di[benzo]- or Tetra[benzo] Derivatives and Oxide Anion: Quantum-Chemical Research

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3162 ◽  
Author(s):  
Oleg V. Mikhailov ◽  
Denis V. Chachkov
Keyword(s):  
Quantum Chemical ◽  
Density Functional ◽  
Nbo Analysis ◽  
Macrocyclic Complexes ◽  
Molecular Structures ◽  
Chemical Research ◽  
Functional Theory ◽  
Chemical Modeling ◽  
The Density Functional Theory ◽  
Oxidation State Of Copper

Using the data of a quantum chemical modeling of molecular structures obtained by the density functional theory (DFT), the possibility of the existence of a copper macrocyclic complexes with 3,7,11,15-tetraazaaporphine, trans-di[benzo] 3,7,11,15-tetraazaaporphine or tetra[benzo] 3,7,11,15-tetraazaaporphine and oxide anion where oxidation state of copper is IV, was shown. The values of the parameters of molecular structures and NBO analysis for such complexes were presented, too.

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