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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >The synthesis,characterisation and reactivity of 2-phosphanylethylcyclopentadienyl complexes of cobalt,rhodium and iridium
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The synthesis,characterisation and reactivity of 2-phosphanylethylcyclopentadienyl complexes of cobalt,rhodium and iridium

机译：钴，铑和铱的2-膦基乙基环戊二烯基配合物的合成，表征和反应活性

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摘要

2-Phosphanylethylcyclopentadienyl lithium compounds,Li[C_5R'_4(CH_2)_2PR_2](R = Et,R' = H or Me,R = Ph,R' = Me),have been prepared from the reaction of spirohydrocarbons C_5R'_4(C_2H_4)with LiPR_2.C_5Et_4HSiMe_2CH_2PMe_2,was prepared from reaction of Li[C_5Et_4] with Me_2SiCl_2 followed by Me_2PCH_2Li.The lithium salts were reacted with [RHCl(CO)_2]_2,[IrCl(CO)_3] or [CO_2(CO)_8] to give [M(C_5R'_4(CH_2)_2PR_2)(CO)](M = Rh,R = Et,R' = H or Me,R = Ph,R' = Me;M = Ir or Co,R = Et,R' = Me),which have been fully characterised,in many cases crystallographically as monomers with coordination of the phosphorus atom and the cyclopentadienyl ring.The values of v_(co)for these complexes are usually lower than those for the analogous complexes without the bridge between the cyclopentadienyl ring and the phosphine,the exception being [Rh(Cp'(CH_2)_2PEt_2)(CO)](Cp' = C_5Me_4),the most electron rich of the complexes.[Rh(C_5Et_4SiMe_2CH_2PMe_2)(CO)] may be a dimer.[CO_2(CO)_8] reacts with C_5H_5(CH_2)_2PEt_2 or C_5Et_4HSiMe_2CH_2PMe_2(L)to give binuclear complexes of the form [CO_2(CO)_6L_2] with almost linear PCoCoP skeletons.[Rh(Cp'(CH_2)_2PEt_2)(CO)] and [Rh(Cp'(CH_2)_2PPh,)(CO)] are active for methanol carbonylation at 150 deg C and 27 bar CO,with the rate using [Rh(Cp'(CH_2)_2PPh_2)(CO)](0.81 mol dm~(-3)h~(-1))being higher than that for [RhI_2(CO)_2]~-(0.64 mol dm~(-3)h~(-1)).The most electron rich complex,[Rh(Cp'(CH_2)_2PEt_2)(CO)](0.38 mol dm~(-3)h~(-1))gave a comparable rate to [Cp*Rh(PEt_3)(CO)](0.30 mol dm~(-3)h~(-1)),which was unstable towards oxidation of the phosphine.[Rh(Cp'(CH_2)_2PEt_2)I_2],which is inactive for methanol carbonylation,was isolated after the methanol carbonylation reaction using [Rh(Cp'(CH_2)_2PEt_2)(CO)].Neither of [M(Cp'(CH_2)_2PEt_2)(CO)](M = Co or Ir)was active for methanol carbonylation under these conditions,nor under many other conditions investigated,except that [Ir(Cp'(CH_2)_2PEt_2)(CO)] showed some activity at higher temperature(190 deg C),probably as a result of degradation to [IrI_2(CO)_2]~-.[M(Cp'(CH_2)_2PEt_2)(CO)] react with Mel to give [M(Cp'(CH_2)_2PEt_2)(C(O)Me)I](M = Co or Rh)or [Ir(Cp'(CH_2)_2PEt_2)Me(CO)]I.The rates of oxidative addition of Mel to [Rh(C_5H_4(CH_2)_2PEt_2)(CO)] and [Rh(Cp'(CH_2)_2PPh_2)(CO)] are 62 and 1770 times faster than to [Cp*Rh(CO)_2].Methyl migration is slower,however.High pressure NMR studies show that [Co(Cp'(CH_2)_2PEt_2)(CO)] and [Cp*Rh(PEt_3)(CO)] are unstable towards phosphine oxidation and/or quaternisation under methanol carbonylation conditions,but that [Rh(Cp'(CH_2)_2PEt_2)(CO)] does not exhibit phosphine degradation,eventually producing inactive [Rh(Cp'(CH_2)_2PEt_2)I_2] at least under conditions of poor gas mixing.The observation of [Rh(Cp'(CH_2)_2PEt_2)(C(O)Me)I] under methanol carbonylation conditions suggests that the rhodium centre has become so electron rich that reductive elimination of ethanoyl iodide has become rate determining for methanol carbonylation.In addition to the high electron density at rhodium.
机译：由螺碳氢化合物C_5R'_4（R = Et，R'= H或Me，R = Ph，R'= Me）合成了2-膦酰基乙基环戊二烯基锂化合物Li [C_5R'_4（CH_2）_2PR_2]由Li [C_5Et_4]与Me_2SiCl_2然后由Me_2PCH_2Li反应制得具有LiPR_2.C_5Et_4HSiMe_2CH_2PMe_2的C_2H_4。锂盐与[RHCl（CO）_2] _2，[IrCl（CO）_3]或[CO_2（CO） _8]给出[M（C_5R'_4（CH_2）_2PR_2）（CO）]（M = Rh，R = Et，R'= H或Me，R = Ph，R'= Me; M = Ir或Co， R = Et，R'= Me），在许多情况下在晶体学上都是具有磷原子和环戊二烯基环配位的单体。这些配合物的v_（co）值通常低于[Rh（Cp'（CH_2）_2PEt_2）（CO）]（Cp'= C_5Me_4），其中最富电子的化合物。[Rh（C_5Et_4SiMe_2CH_2PMe_2） （CO）]可能是二聚体。[CO_2（CO）_8]与C_5H_5（CH_2）反应_2PEt_2或C_5Et_4HSiMe_2CH_2PMe_2（L）得到具有几乎线性PCoCoP骨架的[CO_2（CO）_6L_2]形式的双核络合物。[Rh（Cp'（CH_2）_2PEt_2）（CO）]和[Rh（Cp'（CH_2）_2PPh ，）（CO）]在150摄氏度和27 bar CO下对甲醇羰基化有活性，速率为[Rh（Cp'（CH_2）_2PPh_2）（CO）]（0.81 mol dm〜（-3）h〜（ -1））高于[RhI_2（CO）_2]〜-（0.64 mol dm〜（-3）h〜（-1））。最富电子的配合物[Rh（Cp'（CH_2）_2PEt_2 ）（CO）]（0.38 mol dm〜（-3）h〜（-1））的速率与[Cp * Rh（PEt_3）（CO）]（0.30 mol dm〜（-3）h〜（- 1）），其对膦的氧化不稳定。[Rh（Cp'（CH_2）_2PEt_2）I_2]对甲醇羰基化没有活性，在使用[Rh（Cp'（CH_2）_2PEt_2在这些条件下，[M（Cp'（CH_2）_2PEt_2）（CO）]（M = Co或Ir）对甲醇羰基化均无活性，但在[Ir（ Cp'（CH_2）_2PEt_2）（CO）]在较高温度（190摄氏度）下表现出一定的活性， [M（Cp'（CH_2）_2PEt_2）（CO）]与Mel反应生成[M（Cp'（CH_2）_2PEt_2）（C（O ）Me）I]（M = Co或Rh）或[Ir（Cp'（CH_2）_2PEt_2）Me（CO）] I。梅尔氧化成[Rh（C_5H_4（CH_2）_2PEt_2）（CO）的速率]和[Rh（Cp'（CH_2）_2PPh_2）（CO）]分别比[Cp * Rh（CO）_2]快62和1770倍。但是，甲基迁移较慢。高压NMR研究表明[Co（ Cp'（CH_2）_2PEt_2）（CO）]和[Cp * Rh（PEt_3）（CO）]在甲醇羰基化条件下对膦氧化和/或季铵化反应不稳定，但是[Rh（Cp'（CH_2）_2PEt_2）（ CO）]不会显示出膦的降解，至少在不良气体混合条件下最终会产生无活性的[Rh（Cp'（CH_2）_2PEt_2）I_2]。[Rh（Cp'（CH_2）_2PEt_2）（C（O ）（Me）I]在甲醇羰基化条件下表明，铑中心变得非常富电子，以至于乙炔碘化物的还原消除成为决定甲醇羰基化的速率。铑中的高电子密度。

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