Precursors to clusters with the topology of the P(super N) cluster of nitrogenase: Edge-bridged double cubane clusters [(Tp)(sub 2)Mo2Fe6S8L4](super z): Synthesis, structures, and electron transfer series

The existence of a three-member electron-transfer series of single cubanes [(Tp)MoFe3S4](super z) (z = 3-, 2-, 1-) and a four-member series of double cubanes [(Tp)(sub 2)Mo2Fe6S8L4](super z) (z = 4-, 3-, 2-, 1-) with L = F(super -), Cl(super -), N3, PhS(super -) is showed by electrochemical methods, cluster synthesis and X-ray structure determinations. The synthesis and structure of [(Tp)(sub 2)Mo2Fe6S8F2.H2O](super 3-), a new topological analogue of the P(super N) cluster of nitrogenase, is presented (Tp = hydrotris(pyrazolyl)borate(1-)).