کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9591473 | 1507016 | 2005 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
A potential route to the formation of alkylidene ligand from two mutually cis alkene ligands: a DFT study
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
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چکیده انگلیسی
The possible reaction pathways have been studied for the transformation of cis-[W(CO)4(η2-C2H4)2] into alkylidene complex by density functional theory (B3LYP) calculations in order to explain how the catalytically active alkylidene species can be formed from the bis-olefin complexes of tungsten. It was found that the two-electron oxidation of cis-[W(CO)4(η2-C2H4)2] (2et) to its dicationic form cis-[W(CO)4(η2-C2H4)2]2+ (2et2+) allowed for the transformation of this complex to tungstacyclopentane [W(CO)4(C4H8)]2+ (cp2+) at lower energy (ÎH=24 and ÎG=36 kJ molâ1) than in the case of the neutral compound 2et (ÎH=105 and ÎG=108 kJ molâ1). The electronic structure and energy of the initial 2et2+, as well as the mechanism of its interconversion to the tungstacyclopentane complex cp2+ and the final butylidene complex [W(CO)4(=CHC3H7)]2+ (but2+) were determined. An activation barrier ÎH# for the formation of the cp2+ and but2+ complexes was found to be 48 and 87 kJ molâ1, respectively. The butylidene complex but2+ is lower in energy than the tungstacyclopentane complex cp2+ and remains more stable than the initial cis-bis(ethene) complex 2et2+. The structures of two potential hydrido complexes [W(CO)4H(C4H7)]2+ (Hcp2+) are also discussed. The theoretical results are compared with available experimental data, as well as the results of theoretical studies that have been carried out on the related systems.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure: THEOCHEM - Volume 718, Issues 1â3, 31 March 2005, Pages 191-201
Journal: Journal of Molecular Structure: THEOCHEM - Volume 718, Issues 1â3, 31 March 2005, Pages 191-201
نویسندگان
JarosÅaw Handzlik, Marcin Górski, Teresa SzymaÅska-Buzar,