Models of the iron-only hydrogenase:: Reactions of [Fe2(CO)6(μ-pdt)] with small bite-angle diphosphines yielding bridge and chelate diphosphine complexes [Fe2(CO)4(diphosphine)(μ-pdt)]
Models of the iron-only hydrogenase:: Reactions of [Fe2(CO)6(μ-pdt)] with small bite-angle diphosphines yielding bridge and chelate diphosphine complexes [Fe2(CO)4(diphosphine)(μ-pdt)]
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DOI：
10.1016/j.jorganchem.2007.05.050
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发表时间：
2007-08-15
影响因子：
2.3
通讯作者：
Richards, Idris
中科院分区：
文献类型：
--
作者：
Adam, Fatima I.;Hogarth, Graeme;Richards, Idris
研究了[Fe-2（CO）（6）（mu-pdt）]（1）（pdt = SCH_2CH_2CH_2S）与小咬角双膦的反应。取决于二膦的性质和反应条件，可以形成一系列产物。与双（二苯基膦基）甲烷（dppm）一起，在甲苯中的热分解导致分别形成桥和螯合异构体[Fe-2（CO）（4）（mu-dppm）（mu-pdt）]（2）和[Fe-2（CO）（4）（kappa（2）-dppm）（mu-pdt）]（3）的混合物。两者都已被晶体学表征，3是第一排双核系统中螯合dppm配体的罕见实例。室温下，在MeCN中加入Me 3 NO中心点2 H（2）O，初步形成单齿配合物[Fe-2（CO）（5）（kappa（1）-dppm）（mu-pdt）]（4）。升温4至100摄氏度导致缓慢转化为2，而氧化（在氧化铝上）得到[Fe-2（CO）（5）（kappa（1）-dppmO）（mu-pdt）]（5）。用双（二环己基膦基）甲烷（dcpm），在甲苯中加热干净地得到[Fe-2（CO）（4）（mu-dcpm）（mu-pdt）]（6）。在Me 3 NO中心点2 H（2）O的MeCN中，反应不干净，因为膦被氧化，但可以在光谱上看到单齿[Fe-2（CO）（5）（kappa（1）-dcpm）（mu-pdt）]（7）。用1，2-二（二苯基膦基）苯（dppb）和顺式-1，2-双（二苯基膦基）乙烯（dppv）螯合物[Fe-2（CO）（4）（kappa（2）-dppb）（mu-pdt）]（8）和[Fe-2（CO）（4）（kappa（2）-dppv）（mu-pdt）]（9）分别是所有条件下的最终产物，尽管也分离出少量的[Fe-2（CO）（5）（kappa（2）-dppvO）（mu-pdt）]（10）。2与HBF 4的质子化提供了稳定性差的阳离子，而6中更碱性的二铁中心容易形成稳定的桥接-氢化物络合物[（mu-H）Fe-2（CO）（4）（mu-dcpm）（mu-pdt）][BF 4]（11），其已被晶体学表征。(c)2007 Elsevier B. V.保留所有权利。
Reactions of [Fe-2(CO)(6)(mu-pdt)] (1) (pdt = SCH2CH2CH2S) and small bite-angle diphosphines have been studied. A range of products can be formed being dependent upon the nature of the diphosphine and reaction conditions. With bis(diphenylphosphino)methane (dppm), thermolysis in toluene leads to the formation of a mixture of bridge and chelate isomers [Fe-2(CO)(4)(mu-dppm)(mu-pdt)] (2) and [Fe-2(CO)(4)(kappa(2)-dppm)(mu-pdt)] (3), respectively. Both have been crystallographically characterised, 3 being a rare example of a chelating dppm ligand in a first row binuclear system. At room temperature in MeCN with added Me3NO center dot 2H(2)O, the monodentate complex [Fe-2(CO)(5)(kappa(1)-dppm)(mu-pdt)] (4) is initially formed. Warming 4 to 100 degrees C leads the slow conversion to 2, while oxidation (on alumina) gives [Fe-2(CO)(5)(kappa(1)-dppmO)(mu-pdt)] (5). With bis(dicyclohexylphosphino)methane (dcpm), heating in toluene cleanly affords [Fe-2(CO)(4)(mu-dcpm)(mu-pdt)] (6). With Me3NO center dot 2H(2)O in MeCN the reaction is not clean as the phosphine is oxidised but monodentate [Fe-2(CO)(5)(kappa(1)-dcpm)(mu-pdt)] (7) can be seen spectroscopically. With 1,2-bis(diphenylphosphino) benzene (dppb) and cis-1,2-bis(diphenylphosphino)ethene (dppv) the chelate complexes [Fe-2(CO)(4)(kappa(2)-dppb)(mu-pdt)] (8) and [Fe-2(CO)(4)(kappa(2)-dppv)(mu-pdt)] (9), respectively are the final products under all conditions, although a small amount of [Fe-2(CO)(5)(kappa(2)-dppvO)(mu-pdt)] (10) was also isolated. Protonation of 2 with HBF4 affords a cation with poor stability while with the more basic diiron centre in 6 readily forms the stable bridging-hydride complex [(mu-H)Fe-2(CO)(4)(mu-dcpm)(mu-pdt)][BF4] (11) which has been crystallographically characterised. (c) 2007 Elsevier B.V. All rights reserved.