Synthesis and Reactions of Nickel(0) 2-Cyclohexyne Complexes and X-ray Crystal Structure of Ni(
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- 作者：Martin A. Bennett ; Julian A. Johnson ; and Anthony C. Willis
- 刊名：Organometallics
- 出版年：1996
- 出版时间：January 9, 1996
- 年：1996
- 卷：15
- 期：1
- 页码：68 - 74
- 全文大小：268K
- 年卷期：v.15,no.1(January 9, 1996)
- ISSN：1520-6041
文摘
Reduction of 1,2-dibromocyclohexene with 1% sodium amalgam in thepresence of Ni(
2-C2H4)L2 gives cyclohexynenickel(0) complexesNi(2-C6H8)L2[L2 = 2PPh3 (1), dcpe(2), 2PEt3(3); dcpe = 1,2-bis(dicyclohexylphosphino)ethane,Cy2PCH2CH2PCy2],which are structurallysimilar to, but less stable than, the corresponding platinum(0)compounds. The crystalstructure of 2 has been determined. The moleculecontains a nickel atom bound to2-cyclohexyne [Ni-C(1) = 1.875(4) Å,Ni-C(2) = 1.867(4) Å] and to dcpe [Ni-P(1) =2.139(1) Å, Ni-P(2) = 2.138(1) Å]. The geometry is close totrigonal planar if the midpoint of thecoordinated triple bond is regarded as occupying one coordination site,and the C=C distance[1.272(5) Å] is slightly less than that inPt(2-C6H8)(PPh3)2[1.297(8) Å]. Complex 2 reactswith methyl iodide and with CO2 to give insertion productscontaining nickel(II), NiI(2-MeC6H8)(dcpe) (7) andNi{C6H8C(O)O}(dcpe)(9),respectively. Dimethyl acetylenedicarboxylate inserts into the Ni-C 
-bond of 9 to give aseven-membered nickelacycleNi{C(CO2Me)=C(CO2Me)C6H8C(O)O}(dcpe)(10).
2-C2H4)L2 gives cyclohexynenickel(0) complexesNi(2-C6H8)L2[L2 = 2PPh3 (1), dcpe(2), 2PEt3(3); dcpe = 1,2-bis(dicyclohexylphosphino)ethane,Cy2PCH2CH2PCy2],which are structurallysimilar to, but less stable than, the corresponding platinum(0)compounds. The crystalstructure of 2 has been determined. The moleculecontains a nickel atom bound to2-cyclohexyne [Ni-C(1) = 1.875(4) Å,Ni-C(2) = 1.867(4) Å] and to dcpe [Ni-P(1) =2.139(1) Å, Ni-P(2) = 2.138(1) Å]. The geometry is close totrigonal planar if the midpoint of thecoordinated triple bond is regarded as occupying one coordination site,and the C=C distance[1.272(5) Å] is slightly less than that inPt(2-C6H8)(PPh3)2[1.297(8) Å]. Complex 2 reactswith methyl iodide and with CO2 to give insertion productscontaining nickel(II), NiI(2-MeC6H8)(dcpe) (7) andNi{C6H8C(O)O}(dcpe)(9),respectively. Dimethyl acetylenedicarboxylate inserts into the Ni-C -bond of 9 to give aseven-membered nickelacycleNi{C(CO2Me)=C(CO2Me)C6H8C(O)O}(dcpe)(10).