Pyridine‐Based Oligonitriles as Pincer Ligands for Palladium(II), Copper(II), Cobalt(II), and Nickel(II) Ions
Pyridine‐Based Oligonitriles as Pincer Ligands for Palladium(II), Copper(II), Cobalt(II), and Nickel(II) Ions
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吡啶基寡腈作为钯 (II)、铜 (II)、钴 (II) 和镍 (II) 离子的钳配体
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发表时间：
2005
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通讯作者：
E. Würthwein
中科院分区：
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作者：
Henrik Behrens;R. Fröhlich;E. Würthwein
1-氧杂-3，5-二嗪鎓盐2和3通过丙胺的亲核开环分别以34%和57%的产率得到新的多齿、支化、钳型配体4和5。1-氧杂-3，5-二嗪鎓盐2和3是由吡啶-2，6-二羰基二氯（1）在五氯化锑和四氯化锡存在下分别用二甲基氰胺和二异丙基氰胺处理制得的。4的结构，其特征在于由一个强烈扭曲的N-酰基低聚腈臂，由X-射线晶体学确定。配体4以其短臂和长臂分别与乙酸钯（II）和氯化铜（II）形成螯合物4-·Pd（OAc）+和4·CuCl 2。4-·Pd（OAc）+在Suzuki-Miyaura交叉偶联反应中表现出显著的催化活性。钳型配体5在用相应的金属盐处理后得到螯合络合物5·Co（ClO 4）2·DMF、5·CoCl 2和5·Ni（ClO 4）2·DMF。这三种配合物均为八面体构型，DMF或氯离子占据第六配位。在Co Ⅱ配合物中，5·CoCl 2为顺式构型，5·Co（ClO 4）2·DMF为反式构型.在所有情况下，5充当五齿配体。所有的金属配合物，其特征在于通过X-射线衍射。（© Wiley-VCH Verlag GmbH & Co. KGaA，69451魏因海姆，德国，2005）
Nucleophilic ring opening of the 1-oxa-3,5-diazinium salts 2 and 3 by propylamine furnishes the new polydentate, branched, pincer-type ligands 4 and 5, respectively, in 34 and 57 % yield. The 1-oxa-3,5-diazinium salts 2 and 3 were prepared from pyridine-2,6-dicarbonyl dichloride (1) by treatment with dimethylcyanamide and diisopropylcyanamide in the presence of antimony pentachloride and tin tetrachloride, respectively. The structure of 4, which is characterised by a strongly twisted N-acyloligonitrile arm, was determined by X-ray crystallography. The ligand 4, with its short and long arms, forms chelate complexes 4–·Pd(OAc)+ and 4·CuCl2when treated with palladium(II) acetate and copper(II) chloride, respectively. 4–·Pd(OAc)+ shows remarkable catalytic activity in Suzuki–Miyaura cross-coupling reactions. The pincer-type ligand 5 gives the chelate complexes 5·Co(ClO4)2·DMF, 5·CoCl2 and 5·Ni(ClO4)2·DMF upon treatment with the respective metal salts. These three complexes show octahedral configuration, with DMF or chloride occuping the sixth coordination site. For the CoII complexes a cis configuration is oberserved for 5·CoCl2and a trans configuration for 5·Co(ClO4)2·DMF. In all cases 5 acts as a pentadentate ligand. All metal complexes were characterised by X-ray diffraction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)