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首页> 外文期刊>Dalton transactions: An international journal of inorganic chemistry >Interplay of bite angle and cone angle effects. A comparison between o-C_6H_4(CH_2PR_2)(PR′ _2) and o-C_6H_4(CH_2PR _2)(CH_2PR′_2) as ligands for Pd-catalysed ethene hydromethoxycarbonylation
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Interplay of bite angle and cone angle effects. A comparison between o-C_6H_4(CH_2PR_2)(PR′ _2) and o-C_6H_4(CH_2PR _2)(CH_2PR′_2) as ligands for Pd-catalysed ethene hydromethoxycarbonylation

机译：咬合角度和锥角效果之间的相互作用。 O-C_6H_4（CH_2PR_2）（PR'_2）和o-C_6H_4（CH_2PR _2）（CH_2PR'_2）作为Pd催化的乙烯加氢甲氧基羰基化配体的比较

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摘要

The following unsymmetrical diphosphines have been prepared: o-C _6H_4(CH_2PtBu_2)(PR _2) where R = P~tBu_2 (L_(3a)); PCg (L_(3b)); PPh_2 (L_(3c)); P(o-C_6H _4CH_3)_2 (L_(3d)); P(o-C _6H_4OCH_3)_2 (L_(3e)) and o-C_6H_4(CH_2PCg)(PCg) (L_(3f)) where PCg is 6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamant-6-yl. Hydromethoxycarbonylation of ethene under commercially relevant conditions has been investigated in the presence of Pd complexes of each of the ligands L _(3a-f) and the results compared with those obtained with the commercially used o-C_6H_4(CH_2P ~tBu_2)_2 (L_(1a)). The Pd complexes of the bulkiest ligands L_(3a), L_(3b) and L_(3f) are highly active catalysts but the Pd complexes of L_(3c), L_(3d) and L_(3e) are completely inactive. The crystal structures of the complexes [PtCl_2(L_(1a))] (1a) and [PtCl_2(L _(3a))] (2a) have been determined and show that the crystallographic bite angles and cone angles are greater for L_(1a) than L_(3a). Solution NMR studies show that the seven-membered chelate in 1a is more rigid than the six-membered chelate in 2a. Treatment of [PtCl(CH_3)(cod)] with L_(3a-f) gave [PtCl(CH3)(L3a-f)] as mixtures of 2 isomers 3a-f and 4a-f. The ratio of the products 4:3 ranges from 100:1 to 1:20, the precise proportion is apparently governed by a balance of two competing factors, steric bulk and the antisymbiotic effect. The palladium complexes [PdCl(CH_3)(L_(3b))] (5b/6b) and [PdCl(CH _3)(L_(3c))] (5c/6c) react with labelled ~(13)CO to give the corresponding acyl species [PdCl(~(13)COCH_3)(L _(3b))] (7b/8b) and [PdCl(~(13)COCH_3)(L _(3c))] (7c/8c). Treatment of [PdCl(~(13)COCH3)(L)] with MeOH gave CH_3 ~(13)COOMe rapidly when L = L_(3b) but very slowly when L = L_(3c) paralleling the contrasting catalytic activity of the Pd complexes of these two ligands.
机译：制备了以下不对称二膦：o-C _6H_4（CH_2PtBu_2）（PR _2）其中R ＝ P〜tBu_2（L_（3a））; PCg（L_（3b））; PPh_2（L_（3c））; P（o-C_6H _4CH_3）_2（L_（3d））; P（oC _6H_4OCH_3）_2（L_（3e））和o-C_6H_4（CH_2PCg）（PCg）（L_（3f）），其中PCg为6-磷酰基2,4,8-三恶唑-1,3,5,7 -四甲基金刚烷基-6-基。在每种配体L _（3a-f）的Pd配合物存在下，研究了在商业相关条件下乙烯的氢甲氧基羰基化作用，并将结果与​​商用o-C_6H_4（CH_2P〜tBu_2）_2（L_ （1a））。最大的配体L_（3a），L_（3b）和L_（3f）的Pd配合物是高活性催化剂，但L_（3c），L_（3d）和L_（3e）的Pd配合物完全没有活性。配合物[PtCl_2（L_（1a））]（1a）和[PtCl_2（L_（3a））]（2a）的晶体结构已经确定，并且显示出L_（）的晶体咬合角和锥角更大。 1a）比L_（3a）。溶液NMR研究表明1a中的7元螯合物比2a中的6元螯合物更坚硬。用L_（3a-f）处理[PtCl（CH_3）（cod）]，得到[PtCl（CH3）（L3a-f）]，为2种异构体3a-f和4a-f的混合物。产品4：3的比例在100：1至1:20之间，确切比例显然受两个竞争因素（空间体积和抗共生效应）的平衡控制。钯配合物[PdCl（CH_3）（L_（3b））]（5b / 6b）和[PdCl（CH _3）（L_（3c））]（5c / 6c）与标记的〜（13）CO反应生成相应的酰基种类[PdCl（〜（13）COCH_3）（L _（3b））]（7b / 8b）和[PdCl（〜（13）COCH_3）（L _（3c））]（7c / 8c）。用MeOH处理[PdCl（〜（13）COCH3）（L）]，当L = L_（3b）时迅速产生CH_3〜（13）COOMe，但当L = L_（3c）时，CH_3〜（13）COOMe非常缓慢，与Pd的对比催化活性平行这两个配体的复合物。

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