Source:http://linkedlifedata.com/resource/pubmed/id/16323919
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| Predicate | Object |
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| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
25
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| pubmed:dateCreated |
2005-12-5
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| pubmed:abstractText |
The reactions between M2(O2CtBu)4, where M=Mo or W, and thienyl-3,4-dicarboxylic acid (0.5-1.5 equiv) in toluene proceed via a series of detectable intermediates to the compounds M8(O2CtBu)4(mu-SC4H2-3,4-{CO2}2)6, which are isolated as air-sensitive yellow (M=Mo) or red (M=W) powders and show parent molecular ions in their mass spectra (MALDI). The structure of the molybdenum complex was determined by single-crystal X-ray crystallography and shown to contain an unusual M8 polygon involving four Mo2 quadruply bonded units linked via the agency of the six 3,4-thienylcarboxylate groups. The structure has crystallographically imposed S4 symmetry and may be described in terms of a highly distorted tetrahedron of Mo2 units or a bisphenoid in which two Mo2 units are linked by a thienyldicarboxylate such that intramolecular Mo2...O bonding is present, while the other thienylcarboxylate bridges merely serve to link these two [Mo2]...[Mo2] units together. The color of the compounds arises from intense M2 delta-to-thienyl pi transitions and, in THF, the complexes are redox-active and show four successive quasi-reversible oxidation waves. The [M8]+ radical cations, generated by one-electron oxidation with AgPF6, are shown to be valence-trapped (class II) by UV-vis-near-IR and electron paramagnetic resonance spectroscopy. These results are supported by the electronic structure calculations on model compounds M8(O2CH)4(mu-SC4H2-3,4-{CO}2)6 employing density functional theory that reveal only a small splitting of the M2 delta manifold via mixing with the 3,4-thienylcarboxylate pi system.
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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 |
0020-1669
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:day |
12
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| pubmed:volume |
44
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
9347-52
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| pubmed:year |
2005
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| pubmed:articleTitle |
New metal-organic polygons involving MM quadruple bonds: M8(O2CtBu)4(mu-SC4H2-3,4-{CO2}2)6 (M=Mo, W).
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| pubmed:affiliation |
Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210-1185, USA.
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| pubmed:publicationType |
Journal Article
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