A diiron dithiolate complex holding a μ-hydride on the iron atoms and a proton on the basic site of a chelating diphosphine ligand was prepared and crystallographically characterized as a structural model of the [FeFe]-hydrogenase active site, and its molecular structure shows the Hμ−⋯HN+ distance is 3.934 Å.
![Graphical abstract: A proton–hydride diiron complex with a base-containing diphosphine ligand relevant to the [FeFe]-hydrogenase active site](http://hg.y866.cn/compound/lib/scimg/usr/1/B811352A.jpg)
