THEORETICAL INVESTIGATION ON THE INSERTION REACTIONS OF THE GERMYLENOIDH2GeLiFWITHRH(R=Cl,SH,PH2)

2013 ◽  
Vol 12 (03) ◽  
pp. 1350003 ◽  
Author(s):  
BING-FEI YAN ◽  
WEN-ZUO LI ◽  
YU-WEI PEI ◽  
QING-ZHONG LI ◽  
JIAN-BO CHENG
Keyword(s):  
Potential Energy ◽  
Gas Phase ◽  
Potential Energy Surfaces ◽  
Stationary Points ◽  
Insertion Reaction ◽  
Insertion Reactions ◽  
Reaction Energies ◽  
Energy Surfaces ◽  
First Time ◽  
Calculated Potential Energy

The insertion reactions of the germylenoid H2GeLiF with RH (R = Cl, SH , PH2) were studied for the first time by using the DFT B3LYP and QCISD methods. The geometries of the stationary points on the potential energy surfaces of the reactions were optimized at the B3LYP/6-311+G (d,p) level of theory. The calculated results indicated that the mechanisms of the insertion reactions of H2GeLiF with HCl , H2S , and PH3are identical to each other. The QCISD/6-311++G(d,p)//B3LYP/6-311+G(d,p) calculated potential energy barriers of the three reactions are 81.80, 123.39 and 205.56 kJ/mol, and the reaction energies for the three reactions are -58.74, -33.51 and -13.35 kJ/mol, respectively. Under the same situation, the insertion reactions should occur easily in the following order H–Cl > H–SH > H–PH2. The insertion reaction in THF solution is easier than in gas phase.

THEORETICAL STUDY ON HBeP- AND HPBe- ANIONS USING MULTICONFIGURATION SECOND-ORDER PERTURBATION THEORY

2012 ◽  
Vol 11 (06) ◽  
pp. 1281-1288
Author(s):  
WEN-ZUO LI ◽  
YU-WEI PEI ◽  
CAI-XIA SUN ◽  
QING-ZHONG LI ◽  
JIAN-BO CHENG
Keyword(s):  
Potential Energy ◽  
Ground State ◽  
Potential Energy Surfaces ◽  
Saddle Points ◽  
Basis Sets ◽  
Stationary Points ◽  
Electron Systems ◽  
Energy Surfaces ◽  
First Time ◽  
Atomic Natural Orbital

Some low-lying states of the nine-valence-electron systems HBeP - and HPBe - anions have been studied for the first time using three methods CASSCF, CASPT2 and B3LYP with the contracted atomic natural orbital (ANO) and cc-pVTZ basis sets. The geometries of all stationary points along the potential energy surfaces were optimized at the CASSCF/ANO, CASPT2/ANO and B3LYP/cc-pVTZ levels. The potential energy curves of isomerization reactions between HBeP - and HPBe - were calculated as a function of HBeP bond angle. The ground and the first excited states of HBeP - are predicted to be X2Π and A2Σ+ states, respectively. The X2Σ+ and A2Π states of the linear HPBe - are both first-order saddle points because they have unique imaginary frequency. Two bent minima M1 and M2 were found along the 12A′ and 12A″ potential energy surfaces, respectively. The calculated results indicated that the ground-state HBeP - is linear, while the ground-state HPBe - is bent.

scholarly journals Quantum Mechanistic Studies of the Oxidation of Ethylene by Rhenium Oxo Complexes

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Emmanuel Adu Fosu ◽  
Collins Obuah ◽  
Louis Hamenu ◽  
Albert Aniagyei ◽  
Michael Kojo Ainooson ◽  
...  
Keyword(s):  
Potential Energy ◽  
Potential Energy Surfaces ◽  
Frontier Molecular Orbital ◽  
Molecular Orbital Calculations ◽  
Oxo Complexes ◽  
Reaction Energies ◽  
Energy Surfaces ◽  
Rhenium Oxo Complexes ◽  
Epoxidation Catalyst ◽  
Addition Pathway

Transition-metal-mediated oxygen transfer reactions are of importance in both industry and academia; thus, a series of rhenium oxo complexes of the type ReO3L (L = O−, Cl−, F−, OH−, Br−, I−) and their effects as oxidation catalysts on ethylene have been studied. The activation and reaction energies for the addition pathways involving multiple spin states (singlet and triplet) have been computed. In all cases, structures on the singlet potential energy surfaces showed higher stability compared to their counterparts on the triplet potential energy surfaces (PESs). Frontier Molecular Orbital calculations show electrons flow from the HOMO of ethylene to the LUMO of rhenium for all complexes studied except ReO4− where the reverse case occurs. In the reaction between ReO3L (L = O−, Cl−, F−, OH−, Br−, and I−) and ethylene, the concerted [3 + 2] addition pathway on the singlet PES leading to the formation of dioxylate intermediate is favored over the [2 + 2] addition pathway leading to the formation of a metallaoxetane intermediate and subsequent rearrangement to the dioxylate. The activation and the reaction energies for the formation of the dioxylate on the singlet PES for the ligands studied followed the order O− > OH− > I− > F− > Br− > Cl− and O− > OH− > F− > I− > Br− > Cl−, respectively. Furthermore, the activation and the reaction energies for the formation of the metallaoxetane intermediate increase in the order O− > OH− > I− > Br− > Cl− > F− and O− > Br− > I− > Cl− > OH− > F−, respectively. The subsequent rearrangement of the metallaoxetane intermediate to the dioxylate is only feasible in the case of ReO4−. Of all the complexes studied, the best dioxylating catalyst is ReO3Cl (singlet surface) and the best epoxidation catalyst is ReO3F (singlet surface).

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