Source:http://linkedlifedata.com/resource/pubmed/id/12487610
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| Predicate | Object |
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| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
51
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| pubmed:dateCreated |
2002-12-18
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| pubmed:abstractText |
Calculations employing density functional theory (Gaussian 98, B3LYP, LANL2DZ, 6-31G) have been undertaken to interrogate the factors influencing the metathesis reaction involving M-M, C-C, and M-C triple bonds for the model compounds M(2)(EH)(6), M(2)(EH)(6)(mu-C(2)H(2)), and [(HE)(3)M(tbd1;CH)](2), where M = Mo, W and E = O, S. Whereas in all cases the ethyne adducts are predicted to be enthalpically favored in the reactions between M(2)(EH)(6) compounds and ethyne, only when M = W and E = O is the alkylidyne product [(HO)(3)W(tbd1;CH)](2) predicted to be more stable than the alkyne adduct. For the reaction M(2)(EH)(6)(mu-C(2)H(2)) --> [(HE)(3)M(tbd1;CH)](2), the deltaG degrees values (kcal mol(-)(1)) are -6 (M = W, E = O), +5 (M = Mo, E = O), +18 (M = W, E = S), and +21 (M = Mo, E = S) and the free energies of activation are calculated to be deltaG() = +19 kcal mol(-)(1) (M = W, E = O) and +34 kcal mol(-)(1) (M = Mo, E = O), where the transition state involves an asymmetric bridged structure M(2)(OH)(4)(mu-OH)(2)(CH)(mu-CH) in which the C-C bond has broken; C.C = 1.89 and 1.98 A for W and Mo, respectively. These results are discussed in terms of the experimental observations of the reactions involving ethyne and the symmetrically substituted alkynes (RCCR, where R = Me, Et) with M(2)(O(t)()Bu)(6) and M(2)(O(t)()Bu)(2)(S(t)()Bu)(4) compounds, where M = Mo, W.
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
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| pubmed:month |
Dec
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| pubmed:issn |
0002-7863
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:day |
25
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| pubmed:volume |
124
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
15351-8
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| pubmed:dateRevised |
2003-11-4
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| pubmed:year |
2002
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| pubmed:articleTitle |
Insights into the metathesis reaction involving M-M, C-C, and M-C triple bonds from computations employing density functional theory on model compounds M2(OH)6 and M2(SH)6, where M = Mo and W.
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| pubmed:affiliation |
Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43085, USA. chisholm@chemistry.ohio-state.edu
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| pubmed:publicationType |
Journal Article
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