Source:http://linkedlifedata.com/resource/pubmed/id/17165771
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| Predicate | Object |
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| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
50
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| pubmed:dateCreated |
2006-12-14
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| pubmed:abstractText |
The unusual formation of planar trimethylenemethane (TMM) dianion complexes of lanthanide metallocenes, [(C5Me5)2Ln]2[mu-eta3:eta3-C(CH2)3] (Ln = Sm, 1; La, 2; Pr, 3; Nd, 4; Y, 5) has been examined by synthesizing examples with metals from La to Y to examine the effects of radial size on structure and to provide closed shell examples for direct comparison with density functional theory (DFT) calculations. Synthetic routes to 1-4 have been expanded from the [(C5Me5)2Ln][(mu-Ph)2BPh2]/neopentyl lithium reaction involving beta-methyl elimination to a [(C5Me5)2Ln][(mu-Ph)2BPh2]/isobutyl lithium route. The synthetic pathways are sensitive to metal radius. To obtain 5, the methylallyl complex, (C5Me5)2Y[CH2C(Me)CH2], 6, was synthesized and treated with [(C5Me5)2YH]x. In the Lu case, the neopentyl complex [(C5Me5)2LuCH2C(CH3)3]x, 7, was isolated instead of the TMM product. X-ray crystallography showed that the metrical parameters of the planar TMM dianions in each complex are similar. The structural data have been compared with DFT calculations on the closed-shell lanthanum and lutetium complexes that suggest only limited covalent interactions with the lanthanide ion. Benzophenone (2 equiv) reacts with 1 to expand the original four-carbon TMM skeleton to a dianionic bis(alkoxide) ligand containing a symmetrically substituted C=CH2 moiety in [(C5Me5)2Sm]2[mu-(OCPh2CH2)2C=CH2], 8. In this reaction, the TMM complex reacts as a bifunctional bisallylic reagent that generates an organic framework containing a central vinyl group.
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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 |
20
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| pubmed:volume |
128
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
16178-89
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| pubmed:year |
2006
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| pubmed:articleTitle |
Planar trimethylenemethane dianion chemistry of lanthanide metallocenes: synthesis, structure, density functional theory analysis, and reactivity of [(C5Me5)2Ln]2[mu-eta3:eta3-C(CH2)(3] Complexes.
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| pubmed:affiliation |
Department of Chemistry, University of California, Irvine, California 92697-2025, USA. wevans@uci.edu
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| pubmed:publicationType |
Journal Article
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