Synthesis, structural characterization, and electrochemical properties of (diphosphine)Ni-bridged butterfly Fe2E2 (E = S, Se, Te) cluster complexes related to [NiFe]-hydrogenases

• The first four Ni-bridged butterfly Fe2Se2 complexes are prepared.
• The first four Ni-bridged butterfly Fe2Te2 complexes are prepared.
• Ten crystal structures for ten new complexes are reported.
• The new complexes could be regarded as models for [NiFe]-hydrogenases.

As the active site models of [NiFe]-hydrogenases, a series of trinuclear complexes (diphosphine)Ni(μ3-E)2Fe2(CO)6 (1−10, diphosphine = dppv, dppb, dppf, dppe, (Ph2PCH2)2NR (R = Me, t-Bu; E = S, Se, Te) has been prepared by the one-pot reactions of (μ-E2)Fe2(CO)6 with Et3BHLi, followed by treatment of the resultant intermediates (μ-LiE)2Fe2(CO)6 with the corresponding mononuclear complexes (diphosphine)NiCl2. All the new complexes 1−10 have been fully characterized by elemental analysis, spectroscopy, and X-ray crystallography. Electrochemical study reveals that reductions of the three representative complexes (dppv)Ni(μ3-E)2Fe2(CO)6 (1, E = S; 3, Se; 8, Te) become easier from the S to Se to Te complexes. Furthermore, electrocatalytic study demonstrates that complexes 1, 3, and 8 are catalysts for proton reduction to hydrogen in the presence of proton source HOTs.

A series of new (diphosphine)Ni-bridged butterfly Fe2E2 (E = S, Se, Te) cluster complexes (1–10) was prepared and crystallographically characterized. Particularly interesting is that the three representative complexes (1, 3, and 8) were found to be electrocatalysts for proton reduction to hydrogen in the presence of HOTs.Figure optionsDownload as PowerPoint slide