Rhenium Complexes Containing the Chiral Tridentate Ferrocenyl Ligand Pigiphos

The paramagnetic Re(III) complex [ReCl3(Pigiphos)] (1) ((R)-(S)-Pigiphos = bis{(R)-1-[(S)-2-(diphenylphosphino)ferrocenyl]ethyl}cyclohexylphosphine) is accessible from [ReCl3(NCMe)(PPh3)2] and the ligand Pigiphos. 1 reacts with an excess of NaBH4, affording the polyhydride complex [ReH5(Pigiphos)] (2), which was shown to be a classic polyhydride (NMR T1(min) = 158 ms). This complex reacts readily with both Brønsted acids and hydride scavengers to give the corresponding cationic tetrahydride species, which was shown to be active in the catalytic hydrogenation of dimethyl itaconate.顺磁性铼(III)配合物[ReCl₃(Pigiphos)]（编号为1）可由[ReCl₃(NCMe)(PPh₃)₂]与配体Pigiphos制备得到，其中((R)-(S)-Pigiphos = 双{(R)-1-[(S)-2-(二苯基膦基)二茂铁基]乙基}环己基膦)。配合物1与过量硼氢化钠（NaBH₄）反应，得到多氢化物配合物[ReH₅(Pigiphos)]（编号为2），该配合物被证实为典型多氢化物（核磁共振（NMR）最小纵向弛豫时间T₁(min) = 158 ms）。该配合物可与布朗斯特酸（Brønsted acids）及氢化物捕获剂顺利反应，生成对应的阳离子四氢化物物种，该物种被证实可催化衣康酸二甲酯的氢化反应。