SOME MOLECULAR-HYDROGEN COMPLEXES OF IRIDIUM
SOME MOLECULAR-HYDROGEN COMPLEXES OF IRIDIUM
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DOI：
10.1021/ja00274a030
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发表时间：
1986-07-09
影响因子：
15
通讯作者：
BONNEVIOT, L
中科院分区：
文献类型：
--
作者：
CRABTREE, RH;LAVIN, M;BONNEVIOT, L
本文报道了新的分子氢配合物[IrH（H_2）（bq）L_2]~+（bq= 7，8-苯并喹啉，L= PPh_3或PCy_3）和[IrH_2（H_2）_2（PCy_3）_2]~+。提出了检测此类复合物的核磁共振Tx标准。描述了配位H2的去质子化。本文讨论了d-烷基氢解反应的机理，提出了一种二氢络合物作为中间体，目的是报道几个新的例子和一种检测分子氢络合物的新方法。我们还讨论了它们的结构，成键，光谱，和氢活化的相关性。1984年，第一个公认的稳定的、可分离的二氢络合物[W（H2）（CO）3（PR 3）2] 1的例子，以及通过X射线和中子衍射得到的晶体结构被报道。Cr（CO）6在含H2基质中的光解已显示出产生诸如[Cr（H2）（CO）5] 2的物质，其甚至已显示出在环境温度下在烷烃溶液中短暂存在。我们自己的配合物也有初步的报道。Morris等人4a最近表征了f/-e/w-[M（H2）H（Ph 2 PCH 2CH 2 PPh 2）2] BF 4（M= Fe或Ru），包括铁情况下的X射线结构（HH= 0.89 μ m）。他们在NMR时间尺度上观察到（H2）和MH基团之间的交换，正如我们所做的那样。3在所有这些情况下，H2以非经典的未解离的M（H2）形式结合，而不是经典的解离的MH 2形式。4 b H2的这两种结合模式与CH与金属配合物结合的情况下已知的agostic（C-H-M）和环金属化（CMH）5形式之间存在相似之处。
The new molecular hydrogen complexes [IrH (H2)(bq) L2]+(bq= 7, 8-benzoquinolinate, L= PPh3 or PCy3) and [IrH2 (H2) 2 (PCy3) 2]+ are described. A NMR Tx criterion is proposed for detectingsuch complexes. Deprotonation of the coordinated H2 is described. The mechanism of hydrogenolysis of d alkyls is discussed and a dihydrogen complex proposed as intermediate.The purpose of this paper is to report several new examples and a new way of detecting molecular hydrogen complexes. We also discuss their structure, bonding, spectra, and relevance to hydrogen activation. The first recognized example of a stable, isolable dihydrogen complex,[W (H2)(CO) 3 (PR3) 2], 1 together with its crystal structure by X-ray and neutron diffraction was reported in 1984. Photolysis of Cr (CO) 6 in an H2-containing matrix has been shown to give species such as [Cr (H2)(CO) 5] 2 which has even been shown to have a fleeting existence in alkane solution at ambient temperature. Our own complexes have also been reported in preliminary form. 3 4567Morris et al. 4a have more recently characterized f/-e/w-[M (H2) H (Ph2PCH2CH2PPh2) 2] BF4 (M= Fe or Ru), including an X-ray structure in the iron case (HH= 0.89 Á). They observed exchange between the (H2) and MH groups on the NMR time scale as we had also done. 3 In all these cases, H2 binds in the nonclassical undissociated M (H2) form ratherthan in the classical dissociated MH2 form. 4b There isan analogy between these two binding modes for H2 and the agostic (C-H—M) and cyclometalated (CMH) 5 forms known in the case of CH binding to metal complexes.