Synthetic, spectroscopic, and electrochemical studies of the isomerically-rich [M(CO)(2)(P2P')X](+/0) (M=Mn, Re; X=Cl, Br; P2P'=eta(3)-Ph(2)P(CH2)(2)P(Ph)(CH2)(2)PPh(2)) system: Structural characterization of a novel pair of diastereoisomers of cis,mer-Re(CO)(2)(P2P')Cl
Synthetic, spectroscopic, and electrochemical studies of the isomerically-rich [M(CO)(2)(P2P')X](+/0) (M=Mn, Re; X=Cl, Br; P2P'=eta(3)-Ph(2)P(CH2)(2)P(Ph)(CH2)(2)PPh(2)) system: Structural characterization of a novel pair of diastereoisomers of cis,mer-Re(CO)(2)(P2P')Cl
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DOI：
10.1021/ic961295d
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发表时间：
1997-03-12
影响因子：
4.6
通讯作者：
Walter, JN
中科院分区：
文献类型：
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作者：
Bond, AM;Colton, R;Walter, JN
Mn（CO）（5）X（X = Cl，Br）与Ph（2）P（CH_2）（2）P（Ph）（CH_2）（2）PPh（2）（P_2 P ′）在邻二甲苯中反应，生成了异构纯的顺式异构体Mn（CO）（2）（η（3）-P_2 P ′）X。在二氯甲烷（0.1 M Bu（4）NPF（6））中的循环伏安图显示可逆的单电子氧化（过程1，E（1/2）= 0.142 V），得到顺式，聚体-[Mn（CO）（2）（P2P '）X]（+）。然而，在室温下的丙酮（0.1 M Bu（4）NPF（6））中，过程1是不可逆的，并且观察到另外的氧化还原过程4（E（1/2）= 0.048 V）。过程4在低温下未观察到，并且在丙酮中在较高温度下它与过程1合并，并且还出现新的可逆氧化还原对（过程5，E（1/2）=-0.411V）。电解、化学氧化和随后的还原的组合，再加上IR和P-31 NMR光谱和电喷雾质谱（ESMS），用于显示过程1、4和5都与Mn（CO）（2）（P2P '）X和[Mn（CO）（2）（P2P'）X]（+）的不同异构体的氧化还原和互变反应有关。由于[Mn（CO）（2）（P2P '）X]（+）的不同异构体的氧化，在非常正的电位下观察到其他不可逆过程。Re（CO）（5）X与P2P'在均三甲苯中反应生成可溶性产物和少量沉淀。主要的可溶性产物被鉴定为cis，mer-Re（CO）（2）（P2P '）X，并且氧化化学类似于锰类似物。沉淀物由五种化合物组成，其中一种为顺式，mer-Re（CO）（2）（P2P '）X。新化合物A-D的结构鉴定如下：A为cis，mer-{Re（CO）（2）（P2P '）X}（2），一个具有桥连P2P'配体的二聚体。B的光谱数据表明它是一种顺式，聚-Re（CO）（2）（P2P '）X的形式，但与主产物不同。化合物C为cis，fac-Re（CO）（2）P（P2P '）X，化合物D为fac-[Re（CO）（3）（P2P'）]X。顺式，mer-Re（CO）（2）（P2P '）Cl（I）和顺式，mer-Re（CO）（2）（P2P'）Cl（II）的晶体结构表明，化合物是具有与P2P'配体相同的mer几何形状的非对映异构体，这必然会在P2P'配体的一侧产生由三个苯环形成的空腔。这两种化合物的配位几何结构的不同之处仅在于相互反式氯和羰基配体的互换。在（I）中，羰基配体在空腔内，并且在（II）中，氯配体在空腔内。
Reaction of Mn(CO)(5)X (X = Cl, Br) with Ph(2)P(CH2)(2)P(Ph)(CH2)(2)PPh(2) (P2P') in refluxing xylene led to the formation of isomerically pure Cis,mer-Mn(CO)(2)(eta(3)-P2P')X. Cyclic voltammograms in dichloromethane (0.1 M Bu(4)NPF(6)) show a reversible one-electron oxidation (process 1, E(1/2) = 0.142 V) to give cis,mer-[Mn(CO)(2)(P2P')X](+). However, in acetone (0.1 M Bu(4)NPF(6)) at room temperature, process 1 is not reversible and an additional redox process 4 (E(1/2) = 0.048 V) is observed. Process 4 is not observed at low temperatures, and at higher temperatures in acetone it merges with process 1 and also a new reversible redox couple (process 5, E(1/2) = -0.411 V) appears. A combination of electrolyses, chemical oxidation, and subsequent reduction, coupled with IR and P-31 NMR spectroscopies and electrospray mass spectrometry (ESMS), is used to show that processes 1, 4, and 5 are all associated with redox and interconversion reactions of different isomers of Mn(CO)(2)(P2P')X and [Mn(CO)(2)(P2P')X](+). Other irreversible processes due to oxidation of the different isomers of [Mn(CO)(2)(P2P')X](+) are observed at very positive potentials. Reaction between Re(CO)(5)X and P2P' in refluxing mesitylene gives a soluble product and a small amount of precipitate. The major soluble product was identified as cis,mer-Re(CO)(2)(P2P')X, and the oxidative chemistry is similar to that of the manganese analogues. The precipitate consists of five compounds, one of which was cis,mer-Re(CO)(2)(P2P')X. The new compounds A-D were identified as follows: A is cis,mer-{Re(CO)(2)(P2P')X}(2), a dimeric species with bridging P2P' ligands. The spectroscopic data for B indicated that it was a form of cis,mer-Re(CO)(2)(P2P')X, but not the same as the major product. Compound C is cis,fac-Re(CO)(2)P(P2P')X, and compound D was shown to be fac-[Re(CO)(3)(P2P')]X. The crystal structures of cis,mer-Re(CO)(2)(P2P')CI(I) and cis,mer-Re(CO)(2)(P2P') Cl(II) show the compounds to be diastereoisomers with the same mer geometry of the P2P' ligand, which of necessity generates a cavity formed by three phenyl rings on one side of the rhenium atom. The coordination geometry of the two compounds differ only by the interchange of the mutually trans chloro and carbonyl ligands. In (I) the carbonyl ligand is within the cavity and in (II) the chloro ligand is within the cavity.