Synthesis, Structural Characterization, and Properties of Some Functionalized Phosphine-Containing Diiron Complexes As Models for the Active Site of [FeFe]-Hydrogenases

The first phosphinobenzaldehyde- and phosphinoporphyrin-functionalized model complexes (1–4) have been synthesized and structurally characterized. Thus, reaction of diiron complex [(μ-SCH2)2CH2]­Fe2(CO)6 or [(μ-SCH2)2NC6H4CO2Me-p]­Fe2(CO)6 with p-Ph2PC6H4CHO in the presence of Me3NO gave the phosphinobenzaldehyde-functionalized model complexes [(μ-SCH2)2CH2]­Fe2(CO)5(p-Ph2PC6H4CHO) (1) and [(μ-SCH2)2NC6H4CO2Me-p]­Fe2(CO)5(p-Ph2PC6H4CHO) (2) in 61% and 71% yields, respectively. Further reaction of 1 or 2 with PhCHO, pyrrole, and BF3·OEt2 followed by treatment with p-chloranil resulted in formation of the phosphinoporphyrin-functionalized model complexes 5-{[(μ-SCH2)2CH2]­Fe2(CO)5(p-Ph2PC6H4)}-10,15,20-triphenylporphyrin (3) and 5-{[(μ-SCH2)2NC6H4CO2Me-p]­Fe2(CO)5(p-Ph2PC6H4)}-10,15,20-triphenylporphyrin (4) in 19% and 18% yields, respectively. While the new complexes 1–4 were characterized by elemental analysis and spectroscopy, the structures of 1, 3, and 4 were confirmed by X-ray crystallography. Particularly interesting is that complex 4 was found to be a catalyst for the photoinduced H2 production in the presence of the electron donor EtSH and the proton source HOAc.首例膦苯甲醛（phosphinobenzaldehyde）与膦卟啉（phosphinoporphyrin）功能化的模型配合物（1~4）已被合成并完成结构表征。具体而言，双核铁配合物[(μ-SCH2)2CH2]Fe2(CO)6或[(μ-SCH2)2NC6H4CO2Me-p]Fe2(CO)6与对二苯基膦苯甲醛（p-Ph2PC6H4CHO）在三甲基胺N-氧化物（Me3NO）存在下反应，分别以61%和71%的产率得到膦苯甲醛功能化模型配合物[(μ-SCH2)2CH2]Fe2(CO)5(p-Ph2PC6H4CHO)（1）与[(μ-SCH2)2NC6H4CO2Me-p]Fe2(CO)5(p-Ph2PC6H4CHO)（2）。进一步将配合物1或2与苯甲醛（PhCHO）、吡咯及三氟化硼乙醚络合物（BF3·OEt2）反应，再经对四氯苯醌（p-chloranil）氧化处理，分别以19%和18%的产率得到膦卟啉功能化模型配合物5-{[(μ-SCH2)2CH2]Fe2(CO)5(p-Ph2PC6H4)}-10,15,20-三苯基卟啉（3）与5-{[(μ-SCH2)2NC6H4CO2Me-p]Fe2(CO)5(p-Ph2PC6H4)}-10,15,20-三苯基卟啉（4）。上述新型配合物1~4均通过元素分析与光谱表征完成结构鉴定，而配合物1、3与4的晶体结构则经X射线单晶衍射（X-ray crystallography）得以确认。尤为值得关注的是，配合物4在电子给体乙硫醇（EtSH）与质子源乙酸（HOAc）的存在下，可作为光致产氢反应的催化剂。