Source:http://linkedlifedata.com/resource/pubmed/id/20924525
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
43
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pubmed:dateCreated |
2010-10-28
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pubmed:abstractText |
A series of complexes of the type Tp'Rh(PR(3))(Ar(F))H, where PR(3) = PMe(3) (3) and PMe(2)Ph (9), Ar(F) = C(6)F(5) (a), 2,3,4,5-C(6)F(4)H (b), 2,3,5,6-C(6)F(4)H (c), 2,4,6-C(6)F(3)H(2) (d), 2,3-C(6)F(2)H(3) (e), 2,5-C(6)F(2)H(3) (g), and 2-C(6)FH(4) (h) and Tp' = tris(3,5-dimethylpyrazolyl)borate, has been synthesized as stable crystalline compounds by the reactions of the [Tp'Rh(PR(3))] fragment with the corresponding fluorinated aromatic hydrocarbons, and their structures were characterized by NMR spectroscopy and elemental analysis together with X-ray crystallography. The kinetics of the reductive eliminations of fluoroarenes from complexes 3a-h in benzene-d(6) solutions at 140 °C were investigated, but were complicated by the formation of the rhodium(I) bisphosphine complex, Tp'Rh(PMe(3))(2) (4). On the other hand, thermal reactions of (9) in THF-d(8) solutions at 120 °C resulted in the formation of an intramolecular C-H bond activated complex of the phenyl group on the phosphorus atom, Tp'Rh(?(2)-C(6)H(4)-2-PMe(2))H (7), which prevents the formation of the corresponding bisphosphine complex. The experimentally determined rates of the reductive eliminations of fluoroarenes from the complexes 9a-h and their kinetic selectivities for formation in competition with the metallacycle have been used to determine relative Rh-CAr(F) bond energies. The Rh-CAr(F) bond energy is found to be dependent on the number of ortho fluorines. A plot of Rh-CAr(F) vs. C-H bond strengths resulted in a line with a slope R(M-C/C-H) of 2.15 that closely matches the DFT calculated value (slope = 2.05).
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pubmed:language |
eng
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pubmed:journal | |
pubmed:status |
PubMed-not-MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
1477-9234
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pubmed:author | |
pubmed:issnType |
Electronic
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pubmed:day |
21
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pubmed:volume |
39
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
10495-509
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pubmed:year |
2010
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pubmed:articleTitle |
Synthesis, structure, and reductive elimination in the series Tp'Rh(PR3)(Ar(F))H; determination of rhodium-carbon bond energies of fluoroaryl substituents.
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pubmed:affiliation |
Department of Chemistry, University of Rochester, Rochester, New York 14627, USA.
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pubmed:publicationType |
Journal Article
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