Design, Syntheses and Application of New Phosphine and Dithiophosphinate Complexes of Nickel: Catalyst Precursors for the Oligomerization of Ethylene
详细信息 查看全文
- 作者：Ronald G. Cavell ; Beth Creed ; Lucio Gelmini ; David J. Law ; Robert McDonald ; Alan R. Sanger ; and Arpad Somogyvari
- 刊名：Inorganic Chemistry
- 出版年：1998
- 出版时间：February 23, 1998
- 年：1998
- 卷：37
- 期：4
- 页码：757 - 763
- 全文大小：197K
- 年卷期：v.37,no.4(February 23, 1998)
- ISSN：1520-510X
文摘
Several new nickel(II) and nickel(0) complexes have beenprepared which are active and selective for theoligomerization of ethylene to higher 
-olefins. Nickel(II)complexes of the typeNiCl(PR3)S2PR'2 (R =Ph, Bu;R' = Me, Ph) contain one bound halide ion, a monodentate phosphine,and a bidentate chelating dithiophosphinateligand. The single-crystal X-ray structure ofNiCl(PPh3)S2PMe2 isreported. Crystal data: triclinic, space groupP
(No. 2), a = 10.288 (2) Å,b = 13.205 (3) Å, c = 16.157 (2) Å, =82.63(1)
, 
= 88.29(1), 
=78.87(2),Z = 4. Final R andRw values were 0.042 and 0.048, respectively.There are two independent molecules A andB in the unit cell. In each case the molecular structure is basedon a distorted square planar Ni(II) center subtendedwith a slightly asymmetrically bound chelated dithiophosphinate ligandwith a relatively tight binding angle (S-Ni-S 87.4). Molecule A is slightly more distorted from thesquare planar geometry (in that the P(V) of thedithiophosphinate chelate deviates more significantly from thecoordination plane) than B. The bond distances(Ni-S (av) (trans to Cl) 2.205(2) Å, Ni-S (av) (trans to thephosphine ligand) 2.254(5) Å, Ni-Cl (av)2.179(5)Å and Ni-P (ave) 2.021(3) Å) do not differ significantly inthe two molecules. Also prepared were thenickel(0)complexes Ni(Ph2P-N=C(H)Ph)4 andNi(Ph2PCH2P(Ph2)NC6F4CN)2.Each of the complexes is more active forthe oligomerization of ethylene than are comparable conventionalcomplexes of nickel with typical phosphineligands. Batch reactions of the nickel complexes in combinationwith a 150 times molar excess ofEtnAlCl3-nintoluene oligomerized ethylene at temperatures below 25 C under0.1-2.8 MPa of ethylene and a lesser amountof inert gas. The catalyst mixtures have high activity (forexample, a rate of 7.64 × 105 mol ofC2(mol ofcat)-1h-1 was observed forNi(Ph(H)NCPPh2)4 with excessdiethylaluminum chloride cocatalyst) and high selectivityto -olefins, in particular 1-butene. The selectivity to1-butene increases with increasing olefin pressure.
-olefins. Nickel(II)complexes of the typeNiCl(PR3)S2PR'2 (R =Ph, Bu;R' = Me, Ph) contain one bound halide ion, a monodentate phosphine,and a bidentate chelating dithiophosphinateligand. The single-crystal X-ray structure ofNiCl(PPh3)S2PMe2 isreported. Crystal data: triclinic, space groupP (No. 2), a = 10.288 (2) Å,b = 13.205 (3) Å, c = 16.157 (2) Å, =82.63(1), = 88.29(1), =78.87(2),Z = 4. Final R andRw values were 0.042 and 0.048, respectively.There are two independent molecules A andB in the unit cell. In each case the molecular structure is basedon a distorted square planar Ni(II) center subtendedwith a slightly asymmetrically bound chelated dithiophosphinate ligandwith a relatively tight binding angle (S-Ni-S 87.4). Molecule A is slightly more distorted from thesquare planar geometry (in that the P(V) of thedithiophosphinate chelate deviates more significantly from thecoordination plane) than B. The bond distances(Ni-S (av) (trans to Cl) 2.205(2) Å, Ni-S (av) (trans to thephosphine ligand) 2.254(5) Å, Ni-Cl (av)2.179(5)Å and Ni-P (ave) 2.021(3) Å) do not differ significantly inthe two molecules. Also prepared were thenickel(0)complexes Ni(Ph2P-N=C(H)Ph)4 andNi(Ph2PCH2P(Ph2)NC6F4CN)2.Each of the complexes is more active forthe oligomerization of ethylene than are comparable conventionalcomplexes of nickel with typical phosphineligands. Batch reactions of the nickel complexes in combinationwith a 150 times molar excess ofEtnAlCl3-nintoluene oligomerized ethylene at temperatures below 25 C under0.1-2.8 MPa of ethylene and a lesser amountof inert gas. The catalyst mixtures have high activity (forexample, a rate of 7.64 × 105 mol ofC2(mol ofcat)-1h-1 was observed forNi(Ph(H)NCPPh2)4 with excessdiethylaluminum chloride cocatalyst) and high selectivityto -olefins, in particular 1-butene. The selectivity to1-butene increases with increasing olefin pressure.