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首页> 外文期刊>Chemistry: A European journal >New diphosphine ligands containing ethyleneglycol and amino alcohol spacers for the rhodium-catalyzed carbonylation of methanol
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New diphosphine ligands containing ethyleneglycol and amino alcohol spacers for the rhodium-catalyzed carbonylation of methanol

机译：含乙二醇和氨基醇间隔基的新型二膦配体，用于铑催化甲醇羰基化

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摘要

The new diphosphine ligands Ph_2PC_6H_4C(O)X(CH_2)_2OC(O)C_6H_4PPh_2 (1: X = NH; 2: X=NPh; 3: X=O) and Ph_2PC_6H_4C(O)O(CH_2)_2O(CH_2)_2OC(O)C_6H_4PPh_2 (5) as well as the monophosphine ligand Ph_2PC_6H_4C(O)X(CH_2)_2OH (4) have been prepared from 2-diphenylphosphinobenzoic acid and the corresponding amino alcohols or diols. Coordination of the diphosphine ligands to rhodium, iridium, and platinum resulted in the formation of the square-planar complexes [(P-P)Rh(CO)Cl (6: P-P = 1; 7: P-P=2; 8: P-P=3), [(P-P)Rh(CO)Cl]_2 (9: P-P=5), [(P-P)Ir(cod)Cl] (10: P-P=1; 11: P-P=2; 12:P-P=3), [(P-P)Ir(CO)Cl] (13: P-P = 1; 14: P-P =2; 15: P-P=3), and [(P-P)PtI_2] (18: P-P=2). In all complexes, the diphosphine ligands are trans coordinated to the metal center, thanks to the large spacer groups, which allow the two phosphorus atoms to occupy opposite positions in the square-planar coordination geometry. The trans coordination is demonstrated unambiguously by the single-crystal X-ray structure analysis of complex 18. In the case of the diphosphine ligand 5, the spacer group is so large that dinuclear complexes with ligand 5 in bridging positions are formed, maintaining the trans coordination of the P atoms on each metal center, as shown by the crystal structure analysis of 9. The monophosphine ligand 4 reacts with [{Ir(cod)Cl}_2] (cod = cyclooctadiene) to give the simple derivative [(4)Ir(cod)Cl] (16) which is converted into the carbonyl complex [(4)Ir(CO)_2Cl] (17) with carbon monoxide.The crystal structure analysis of 16 also reveals a square-planar coordination geometry in which the phosphine ligand occupies a position cis with respect to the chloro ligand. The diphosphine ligands 1,2,3, and 5 have been tested as cocatalysts in combination with the catalyst precursors [{Rh(CO)_2Cl}_2] and [{Ir(cod)Cl}_2] or [H_2IrCl_6] for the carbonylation of methanol at 170 deg C and 22 bar CO. The best results (TON 800 after 15 min) are obtained for the combination 2/[{Rh(CO)_2Cl}_2]. After the catalytic reaction mixture and can be isolated; it is active for further runs without loss of catalytic activity.
机译：新的二膦配体Ph_2PC_6H_4C（O）X（CH_2）_2OC（O）C_6H_4PPh_2（1：X = NH; 2：X = NPh; 3：X = O）和Ph_2PC_6H_4C（O）O（CH_2）_2O（CH_2）_2OC （O）C_6H_4PPh_2（5）以及单膦配体Ph_2PC_6H_4C（O）X（CH_2）_2OH（4）由2-二苯基膦基苯甲酸和相应的氨基醇或二醇制得。二膦配体与铑，铱和铂的配位导致形成正方形平面的配合物[（PP）Rh（CO）Cl（6：PP = 1; 7：PP = 2; 8：PP = 3） ，[（PP）Rh（CO）Cl] _2（9：PP = 5），[（PP）Ir（cod）Cl]（10：PP = 1; 11：PP = 2; 12：PP = 3）， [（PP）Ir（CO）Cl]（13：PP = 1; 14：PP = 2; 15：PP = 3）和[（PP）PtI_2]（18：PP = 2）。在所有络合物中，由于大的间隔基团，二膦配体反式配位到金属中心，该基团允许两个磷原子在正方形平面配位几何结构中占据相反的位置。通过配合物18的单晶X射线结构分析清楚地证明了反式配位。在二膦配体5的情况下，间隔基非常大，以至于在桥接位置形成了与配体5的双核配合物，从而保持了反式每个金属中心上P原子的配位，如9的晶体结构分析所示。单膦配体4与[{Ir（cod）Cl} _2]（cod =环辛二烯）反应，得到简单的衍生物[（4） Ir（cod）Cl]（16）与一氧化碳转化为羰基配合物[（4）Ir（CO）_2Cl]（17）。16的晶体结构分析还显示了方平面配位几何结构，其中膦配体相对于氯配体占据顺式位置。已测试二膦配体1,2,3和5与助催化剂前体[{Rh（CO）_2Cl} _2]和[{Ir（cod）Cl} _2]或[H_2IrCl_6]一起作为助催化剂的羰基化反应在170℃和22 bar CO的条件下生成甲醇。对于组合2 / [{{Rh（CO）_2Cl} _2]，可获得最佳结果（15分钟后的TON 800）。催化反应后与混合液分离即可;它对进一步运行具有活性，而不会损失催化活性。

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