Unusual reactivity of a sterically hindered diphosphazane ligand, EtN{P(OR)(2)}(2), (R = C6H3(Pr-i)(2)-2,6) towards (eta(3)-allyl)palladium precursors
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Title |
Unusual reactivity of a sterically hindered diphosphazane ligand, EtN{P(OR)(2)}(2), (R = C6H3(Pr-i)(2)-2,6) towards (eta(3)-allyl)palladium precursors
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Creator |
KRISHNA, H
KRISHNAMURTHY, SS NETHAJI, M MURUGAVEL, R PRABUSANKAR, G |
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Subject |
ray crystal-structure
n-p ligands reductive elimination palladium complexes nucleophilic-attack phosphine complexes diaryl ethers zerovalent palladium selective cleavage bicyclic alkenes |
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Description |
The reactivity of (eta(3)-allyl) palladium chloro dimers [(1-R-eta(3)-C3H4)PdCl](2) ( R = H or Me) towards a sterically hindered diphosphazane ligand [EtN{P(OR)(2)}(2)] (R = C6H3(Pr-i)(2)-2,6), has been investigated under different reaction conditions. When the reaction is carried out using NH4PF6 as the halide scavenger, the cationic complex [(1-R-eta(3)-C3H4)Pd{EtN(P(OR)(2))(2)}] PF6 (R = H or Me) is formed as the sole product. In the absence of NH4PF6, the initially formed cationic complex, [(eta(3)-C3H5)Pd{EtN(P(OR)(2))(2)}]Cl, is transformed into a mixture of chloro bridged complexes over a period of 4 days. The dinuclear complexes, [(eta(3)-C3H5)Pd-2(mu-Cl)(2){P(O)(OR)(2)}{P(OR)(2)(NHEt)}] and [Pd(mu-Cl){P(O)(OR)(2)}{P(OR)(2)(NHEt)}](2) are formed by P-N bond hydrolysis, whereas the octa-palladium complex [(eta(3)-C3H5)(2-Cl-eta(3)-C3H4)Pd-4(mu-Cl)(4)(mu-EtN{P(OR)(2)}(2))] (2), is formed as a result of nucleophilic substitution by a chloride ligand at the central carbon of an allyl fragment. The reaction of [EtN{P(OR)(2)}(2)] with [(eta(3)-C3H5)PdCl](2) in the presence of K2CO3 yields a stable dinuclear (eta(3)-allyl)palladium(I) diphosphazane complex, [(eta(3)-C3H5)[mu-EtN{P(OR)(2)}(2)Pd2Cl] which contains a coordinatively unsaturated T-shaped palladium center. This complex exhibits high catalytic activity and high TON's in the catalytic hydrophenylation of norbornene.
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Publisher |
ROYAL SOC CHEMISTRY
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Date |
2011-08-28T23:56:11Z
2011-12-26T12:58:15Z 2011-12-27T05:47:52Z 2011-08-28T23:56:11Z 2011-12-26T12:58:15Z 2011-12-27T05:47:52Z 2007 |
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Type |
Article
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Identifier |
DALTON TRANSACTIONS, (27), 2908-2914
1477-9226 http://dx.doi.org/10.1039/b703308g http://dspace.library.iitb.ac.in/xmlui/handle/10054/11873 http://hdl.handle.net/10054/11873 |
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Language |
en
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