Unravelling the S → O Linkage Photoisomerization Mechanisms in cis- and trans-[Ru(bpy)2(DMSO)2]2+ Using Density Functional Theory

2014 ◽  
Vol 53 (13) ◽  
pp. 6752-6760 ◽  
Author(s):  
Adrien J. Göttle ◽  
Fabienne Alary ◽  
Isabelle M. Dixon ◽  
Jean-Louis Heully ◽  
Martial Boggio-Pasqua
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Functional Theory ◽  
Cis And Trans ◽  
In Cis

scholarly journals Simulation Study of Structural and Electronic Properties for Adducts complexes of Bis(Acetylacetonato)oxoVandium (IV) with 4-(Para-substituted phenyl)-1,2,3-Selenadiazole

2021 ◽  
Vol 2063 (1) ◽  
pp. 012002
Author(s):  
Dalal H Alsawad ◽  
Ali A Al-Riyahee ◽  
Ali J Hameed
Keyword(s):  
Density Functional Theory ◽  
Electronic Properties ◽  
Molecular Orbital ◽  
Density Functional ◽  
Functional Theory ◽  
Structural And Electronic Properties ◽  
Lowest Unoccupied Molecular Orbital ◽  
Reorganization Energies ◽  
Cis And Trans ◽  
Optimized Geometries

Abstract A series of 4-(para-substituted phenyl)-1,2,3-selenadiazole adducts of [VO(acac)2] were studied by density functional theory (DFT) calculations. The 4-(para-substituted phenyl)-1,2,3-selenadiazole molecules have been selected to be bound with vanadium atom in [VO(acac)2] through Se, N2 and N3. The resulting adducts have been investigated in two geometries (cis and trans) in order to show the effect of such structural change on the electronic properties of the studied adducts. The optimized geometries, (binding and reorganization) energies and the spatial distribution of the highest molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the adducts are presented and discussed.

scholarly journals Some DADNE Originated Cyclic Isomers - A DFT Study

2020 ◽  
pp. 137-153
Author(s):  
Lemi Türker
Keyword(s):  
Density Functional Theory ◽  
Spectral Data ◽  
Quantum Chemical ◽  
Density Functional ◽  
Dft Study ◽  
Functional Theory ◽  
Type Molecule ◽  
Cis And Trans ◽  
Ionic Forms

Diaminodinitroethylene (DADNE) has three constitutional isomers, geminal, cis and trans. The geminal one is the well known FOX-7 explosive. It is a push-pull type molecule. In the present study, within the restrictions of density functional theory at the level of B3LYP/6-311++G(d,p), two cyclic dimeric structures of DADNE are investigated quantum chemically. Also their mono ionic forms have been investigated (unrestricted treatment). All the structures are found to be stable. Various quantum chemical and spectral data are collected computationally and discussed.

Mechanisms for anionic butadiene polymerization with alkyl lithium species

2009 ◽  
Vol 87 (7) ◽  
pp. 891-903 ◽  
Author(s):  
Peter Margl
Keyword(s):  
Density Functional Theory ◽  
Industrial Application ◽  
Density Functional ◽  
Room Temperature ◽  
Functional Theory ◽  
Polymer Microstructure ◽  
Low Dielectric ◽  
Butadiene Polymerization ◽  
Polymerization Mixture ◽  
Cis And Trans

Anionic butadiene polymerization by means of [Li-polybutadienyl]x species (x = 1–6, 8) without polar agents was investigated by means of density functional theory (DFT) under conditions relevant to industrial application, namely in a low-dielectric hydrocarbon solvent and at room temperature. The calculations indicate that the dimeric and tetrameric catalyst species together account for the bulk of Li-polybutadienyl species in the polymerization mixture under typical conditions. It is likely that each type of oligomer produces its own “fingerprint” signature polymer microstructure, as there is a systematic variation in the amounts of 1,2- and 1,4-insertions as well as in the preference of cis- and trans-butadiene. According to the calculations, higher aggregated Li species tend to produce more 1,2-insertions and prefer trans- over cis-butadiene insertion, while the dimer prefers trans-butadiene and 1,4-insertions. The dimer closely reproduces the experimentally observed polybutadiene microstructure (5%–10% 1,2-insertion, approximately equal ratios of cis and trans units with a slight predominance of trans). The monomeric catalyst species shows a clear preference for insertion of cis-butadiene over trans-butadiene. Thus, the monomer species is predicted to be present in the polymerization mixture in very small concentrations under normal conditions and the overall polymerization is predicted to be mainly carried out by the dimeric catalyst species.

cis-[(η5-C5H5)Fe(η1-CO)(μ-CO)]2, the poor relative between cis and trans tautomers. A theoretical study of the gas-phase Fe L3-edge and C and O K-edge XAS of trans-/cis-[(η5-C5H5)Fe(η1-CO)(μ-CO)]2.

2021 ◽  
Author(s):  
Silvia Carlotto ◽  
Girolamo Casella ◽  
Mauro Sambi ◽  
Maurizio Casarin
Keyword(s):  
Density Functional Theory ◽  
Gas Phase ◽  
Relative Stability ◽  
Density Functional ◽  
Theoretical Study ◽  
Dielectric Constants ◽  
Functional Theory ◽  
The Poor ◽  
The Density Functional Theory ◽  
Cis And Trans

The relative stability of trans-[(η5-C5H5)Fe(η1-CO)(μ-CO)]2 (trans-I) and cis-I tautomers in vacuum and in solvents with different dielectric constants (ε) has been investigated by exploiting the density functional theory (DFT). Theoretical...

A combined density functional theory and molecular mechanics (QM/MM) study of single site ethylene polymerization catalyzed by [Cp{NC(t-Bu)2}TiR+] in the presence of the counterion (CH3B(C6F5)3–)1

2003 ◽  
Vol 81 (11) ◽  
pp. 1413-1429 ◽  
Author(s):  
Kumar Vanka ◽  
Zhitao Xu ◽  
Tom Ziegler
Keyword(s):  
Density Functional Theory ◽  
Ethylene Polymerization ◽  
Density Functional ◽  
Hydrogen Transfer ◽  
Single Point ◽  
Metal Centre ◽  
Functional Theory ◽  
Tertiary Butyl ◽  
Initiation Step ◽  
Cis And Trans

Calculations have been carried out to investigate the insertion of the ethylene monomer into the Ti–alkyl bond for the systems CpNC(t-Bu)2RTi-µ-Me-B(C6F5)3 (R = Me and Pr), using density functional theory. A validated QM/MM model was used to represent the counterion. The tertiary butyl groups in the ligands were modeled with QM/MM, with hydrogens being used as the capping atoms. Solvent effects were incorporated with single point solvent calculations done with cyclohexane (ε= 2.023) as the solvent. With R = Me (the initiation step), approach of the ethylene cis and trans to the -µ-Me bridge was considered. Insertion was found to be endothermic, with ΔHtot being 12.7 kcal/mol (cis) and 15.5 kcal/mol (trans). The propagation step was then studied for the contact ion pair CpNC(t-Bu)2PrTi-µ-Me-B(C6F5)3 (4). Different conformations of the propyl chain in 4 were considered by altering θ, the dihedral angle formed between the Cβ-Cα-Ti and the Cα-Ti-µC planes. The resting states were found to be at θ = –69° (4a), 177° (4b), and 53° (4c). A maxima was found near θ = 0° (4d). The cis and trans approaches of the ethylene monomer were considered for each of the four cases. The cis approach towards 4a and trans approach towards 4d led to insertion, with displacement of the counterion from the metal centre. The insertion barriers were found to be 17.8 kcal/mol, for the cis approach towards 4b and 16.4 kcal/mol for the trans approach towards 4d. The cis approaches towards conformers 4a and 4c showed common characteristics, with uptake barriers being higher than the subsequent insertion barriers in the two cases. Uptake barriers were 13.6 kcal/mol {TS(4a–7a)} and 10.7 kcal/mol {TS(4c–8a)}. The corresponding insertion barriers were 11.8 kcal/mol {TS(7a–13a)} and 8.4 kcal/mol {TS(8a–13a)}. The trans approaches towards conformers 4a and 4c led to insertion barriers of about 15.1 kcal/mol (lower than for the 4b and 4d cases). The cis approach towards 4d and trans approach towards 4b were found to lead to hydrogen transfer from the propyl chain to monomer, terminating the chain. Termination barriers were high — greater than 19.0 kcal/mol. This suggested that ethylene insertion would be favoured over termination during the propagation step.Key words: homogeneous catalysis, counterion, initiation, propagation, termination.

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