Chromatographic work-up of the initial products of the reaction of the secondary phosphine PPh2H with [Co3(µ3-CR)(CO)9] (R = Me 1a or CO2Me 1b) at 308 K in heptane gave the mono- and bis-substituted complexes [Co3(µ3-CR)(CO)8(PPh2H)] (R = Me 2a or CO2Me 2b) and [Co3(µ3-CR)(CO)7(PPh2H)2] (R  Me 3a or CO2Me 3b) and, in addition, when R = Me, the complex [Co3(µ3-CMe)(µ-Ph2POPPh2)(CO)6(PPh2H)] 4a, in which phosphorusâoxygen bond formation has occurred. Thermolysis of complex 2a at 343 K in heptane gave 1a and [Co3(µ3-CMe)(µ-H)(µ-PPh2)(CO)7] 5a, while thermolysis of 3a under the same conditions afforded 4a, a trace of 5a and [Co3(µ3-CMe)(µ-H)(µ-PPh2)(CO)6(PPh2H)] 6a. Similar reactions with the µ3-CCO2Me capped species 2b and 3b resulted in unstable non-isolable species. Treatment of complexes 3a, 3b with CO at 343 K causes the replacement of first one and then the other PPh2H ligand by CO to give 2a, 2b and then 1a, 1b respectively, while reformation of a phosphorusâhydrogen bond to give initially 2a or 3a can be achieved on carbonylation of either complex 5a or 6a. Substitution of a PPh2H group in 4a can be achieved by purging with CO to give [Co3(µ3-CMe)(µ-Ph2POPPh2)(CO)7] 7a. Complex 7a can also be prepared directly by the reaction of 1a with the diphosphane P2Ph4 as can the analogue [Co3(µ3-CCO2Me)(µ-Ph2POPPh2)(CO)7] 7b on reaction of 1b. The intermediates [Co3(µ3-CR)(CO)8(P2Ph4)] (R = Me 8a or CO2Me 8b) and [Co3(µ3-CR)(µ-P2Ph4)(CO)7] (R = Me 9a or CO2Me 9b) isolated in the reactions can be converted under the same reaction conditions into 7a and 7b respectively. Complex [Co3(µ3-CMe)(µ-Ph2POPPh2)(CO)6(PPhMe2)] 4aâ², the tertiary phosphine analogue of 4a, has been prepared from the reaction of 7a with PPhMe2. The structures of complexes 4aâ² and 5a have been determined by single crystal X-ray diffraction studies.
在308 K的
庚烷中,二次膦PPh2H与[Co3(µ3-CR)(CO)9](R = Me 1a或CO2Me 1b)反应的初始产物经色谱处理后得到单取代和双取代的配合物[Co3(µ3-CR)(CO)8(PPh2H)](R = Me 2a或CO2Me 2b)和[Co3(µ3-CR)(CO)7(PPh2H)2](R = Me 3a或CO2Me 3b),此外,当R = Me时,还得到了配合物[Co3(µ3-CMe)(µ-Ph2P
OPPh2)(CO)6(PPh2H)] 4a,其中发生了
磷-氧键的形成。在343 K的
庚烷中热分解配合物2a得到了1a和[Co3(µ3-CMe)(µ-H)(µ-PPh2)(CO)7] 5a,而相同条件下热分解3a得到了4a、少量的5a和[Co3(µ3-CMe)(µ-H)(µ-PPh2)(CO)6(PPh2H)] 6a。与µ3-CCO2Me封端的物种2b和3b类似的反应产生了不稳定的非可分离物种。在343 K下用CO处理配合物3a, 3b会导致PPh2H
配体被CO逐步替换,分别先得到2a, 2b,然后得到1a, 1b,而在配合物5a或6a的羰基化过程中可以重新形成
磷-氢键,最初得到2a或3a。通过用CO吹扫可以实现4a中PPh2H基团的取代,得到[Co3(µ3-CMe)(µ-Ph2P
OPPh2)(CO)7] 7a。配合物7a也可以通过1a与
二膦P2Ph4的反应直接制备,类似地,通过1b的反应可以制备出相似的[Co3(µ3-CCO2Me)(µ-Ph2P
OPPh2)(CO)7] 7b。在反应中分离得到的中间体[Co3(µ3-CR)(CO)8(P2Ph4)](R = Me 8a或CO2Me 8b)和[Co3(µ3-CR)(µ-P2Ph4)(CO)7](R = Me 9a或CO2Me 9b)可以在相同的反应条件下分别转化为7a和7b。通过7a与PPhMe2的反应,已经制备出了配合物[Co3(µ3-CMe)(µ-Ph2P
OPPh2)(CO)6(PPhMe2)] 4a′,即4a的三级膦类似物。通过单晶X射线衍射研究,已经确定了配合物4a′和5a的结构。