Investigation of Spin–Flip Reactions of Zr + CH3CN by Relativistic Density Functional Theory

Autor:	Qiang Li, Yi-Xiang Qiu, Shu-Guang Wang, Xian-Yang Chen
Rok vydání:	2012
Předmět:	Reaction mechanism Chemistry Molecule Physical chemistry Density functional theory Singlet state Physical and Theoretical Chemistry Spin (physics) Potential energy Transition state Natural bond orbital
Zdroj:	The Journal of Physical Chemistry A. 116:5019-5025
ISSN:	1520-5215 1089-5639
DOI:	10.1021/jp211975e
Popis:	To explore the details of the reaction mechanisms of Zr atoms with acetonitrile molecules, the triplet and singlet spin-state potential energy surfaces have been investigated. Density functional theory (DFT) with the relativistic zero-order regular approximation at the PW91/TZ2P level has been applied. The complicated minimum energy reaction path involves four transition states (TS), stationary states 1-5 and one spin inversion (indicated by ⇒): (3)Zr + NCCH(3) → (3)Zr-η(1)-NCCH(3) ((3)1) → (3)TS(1/2) → (3)Zr-η(2)-(NC)CH(3) ((3)2) → (3)TS(2/3) → (3)ZrH-η(3)-(NCCH(2)) ((3)3) → (3)TS(3/4) → CNZrCH(3) ((3)4) ⇒ (1)TS(4/5) → CN(ZrH)CH(2) ((1)5). The minimum energy crossing point was determined with the help of the DFT fractional-occupation-number approach. The spin inversion leading from the triplet to the singlet state facilitates the activation of a C-H bond, lowering the rearrangement-barrier by 78 kJ/mol. The overall reaction is calculated to be exothermic by about 296 kJ/mol. All intermediate and product species were frequency and NBO analyzed. The species can be rationalized with the help of Lewis type formulas.
Databáze:	OpenAIRE
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