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Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization
Published on: November 27, 2015
Computational studies on ethylene addition to nickel bis(dithiolene)
Li Dang1, Xinzheng Yang, Jia Zhou
1Department of Chemistry, Texas A&M University, College Station, Texas, USA.
The Journal of Physical Chemistry. A
|November 11, 2011
Summary
This study evaluates various density functionals and basis sets for optimizing transition states in ethylene addition to Ni(edt)(2). The ω-B97XD functional provided the most accurate relative energies, closely matching high-level computational methods.
Area of Science:
- Computational Chemistry
- Organometallic Chemistry
- Quantum Chemistry
Background:
- Ethylene addition to Ni(edt)(2) is a key reaction in organometallic chemistry.
- Accurate theoretical modeling is crucial for understanding reaction mechanisms and predicting reactivity.
Purpose of the Study:
- To assess the performance of various density functionals and basis sets for optimizing transition states and intermediates in the ethylene addition to Ni(edt)(2) reaction.
- To compare the accuracy of different computational methods against high-level theoretical benchmarks.
Main Methods:
- Optimization of key transition states and intermediates using eleven density functionals (B3LYP, B3PW91, BMK, HSE06, LC-ωPBE, M05, M06, O3LYP, TPSS, ω-B97X, and ω-B97XD).
- Evaluation of six basis sets (6-31G**, 6-31++G**, cc-pVDZ, aug-cc-pVDZ, cc-pVTZ, and aug-cc-pVTZ).
- Comparison of results with coupled cluster methods (CCSD and CCSD(T)) and complete active space self-consistent field (CASSCF) calculations.
Main Results:
- Optimized geometric parameters showed good agreement across different functionals and basis sets, aligning well with experimental data.
- The ω-B97XD functional yielded relative energies closest to CCSD results.
- M06 and HSE06 functionals provided results comparable to CCSD(T) calculations.
- CASSCF and CASSCF-PT2 calculations confirmed the multireference character of the system, influencing energy variations.
Conclusions:
- The choice of density functional significantly impacts the accuracy of relative energy calculations for this system.
- ω-B97XD is recommended for accurate modeling of this reaction, offering a good balance between accuracy and computational cost.
- The multireference character of the electronic structure is an important factor to consider in theoretical studies of this reaction.
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