1015085-04-7Relevant articles and documents
SHOP-type nickel complexes with alkyl substituents on phosphorus, synthesis and catalytic ethylene oligomerization
Kermagoret, Anthony,Braunstein, Pierre
, p. 822 - 831 (2008/09/20)
The β-keto phosphorus ylides (n-Bu)3P=CHC(O)Ph 6, (t-Bu)2PhP=CHC(O)Ph 7, (t-Bu)Ph2P=CHC(O)Ph 8, (n-Bu) 2PhP=CHC(O)Ph 9, (n-Bu)Ph2P=CHC(O)Ph 10, Me 2PhP=CHC(O)Ph 11 and Ph3P=CHC(O)(o-OMe-C6H 4) 12 have been synthesized in 80-96% yields. The Ni(ii) complexes [N=iPh{Ph2PCHC(O=)(o-OMeC6H4)}(PPh 3)] 13, [N=iPh{Ph(t-Bu)PCHC(O=)Ph}(PPh3)] 15, [N=iPh{(n-Bu)2PCHC(O=)Ph}(PPh3)] 16 and [N=iPh{Ph(n-Bu)PCHC(O=)Ph}(PPh3)] 17 have been prepared by reaction of equimolar amounts of [Ni(COD)2] and PPh3 with the β-keto phosphorus ylides 12 or 8-10, respectively, and characterized by 1H and 31P{1H} NMR spectroscopy. NMR studies and the crystal structure determination of 13 indicated an interaction between the hydrogen atom of the C-H group α to phosphorus and the ether function. The complexes [N=iPh{Ph2PCHC(O=)Ph}(Py)] 18, [N=iPh{Ph(t-Bu)PCHC(O=) Ph}(Py)] 19, [N=iPh{(n-Bu)2PCHC(O=)Ph}(Py)] 20, [N=iPh{Ph(n-Bu) PCHC(O=)Ph}(Py)] 21 and [N=iPh{Me2PCHC(O=)Ph}(Py)] 22 have been isolated from the reactions of [Ni(COD)2] and an excess of pyridine with the β-keto phosphorus ylides Ph3PCH=C(O)Ph 3 or 8-11, respectively, and characterized by 1H and 31P{ 1H} NMR spectroscopy. Ligands 3, 8, 10 and 12 have been used to prepare in situ oligomerization catalysts by reaction with one equiv. of [Ni(COD)2] and PPh3 under an ethylene pressure of 30 or 60 bar. The catalyst prepared in situ from 12, [Ni(COD)2] and PPh 3 was the most active of the series with a TON of 12 700 mol C 2H4 (mol Ni)-1 under 30 bar ethylene. When the β-keto phosphorus ylide 8 was reacted in situ with three equiv. of [Ni(COD)2] and one equiv. of PPh3 under 30 bar of ethylene, ethylene polymerization was observed with a TON of 5500 mol C 2H4 (mol Ni)-1. The Royal Society of Chemistry.
