The Fe4S4 complex {(CH3)(3)NCH2CONH2}(2)[Fe4S4((BuS)-Bu-t)(4)] (1) was synthesized to replicate the ferredoxin active site with a subset of its N-H center dot center dot center dot S hydrogen bonds. The two cationic counterions mimic the polypeptide backbone of ferredoxin (Fd) as amide hydrogen-bond donors to sulfur atoms of the iron-sulfur cluster. X-ray crystallographic data show that the organic sulfur (S-gamma) of one tertbutylthiolate ligand and one inorganic sulfur of the cluster core serve as N-H center dot center dot center dot S hydrogen-bond acceptors. The cluster core of complex 1 is tetragonally elongated in contrast to that of Fd, which is tetragonally compressed. This is the first observation of an elongated [Fe4S4](2+) cluster core. Additionally, this is the first synthetic Fd model in which N-H center dot center dot center dot S hydrogen bonding to a cluster has been achieved.