THE SYNTHESIS, AND PROPERTIES OF FE MO/S CLUSTERS WITH MOFE3S4 CUBANESUBUNITS MO BOUND BIDENTATE OXALATE LIGANDS AND TERMINAL OR BRIDGING CYANIDE LIGANDS - STRUCTURAL CHARACTERIZATION OF (ET4N)3[C2O4)(CN)MOFE3S4CL3] AND (ET4N)5([(C2O4)MOFE3S4CL2]2(MU-CN)(MU-S))/

The reaction of (Et4N)3[(C2O4)MoFe3S4Cl4] (I) with (Et4N)CN affords [( C2O4)(CN)MoFe3S4Cl3]3- (IV) in nearly quantitative yields. The reactio n of I with 0.5 eq. of (Et4N)CN and 0.5 eq. of a source of S2- affords the doubly-bridged double-cubane {[(C2O4)MoFe3S4Cl2]2(mu2-CN)(mu2-S)} 5- (V) in approximately 30% yield. Single crystal X-ray structures wer e determined for IV and V. The mean Fe-Fe, Fe-S and Fe-Cl bond distanc es in IV at 2.713(3), 2.270(5) and 2.214(5) angstrom, are typical for MoFe3S4 cubane-like structures. The Mo-C(N) and C-N bond lengths are f ound at 2.19(2) and 1.04(2) angstrom, respectively. The pentaanion in V consists of two doubly-bridged cubane subunits bridged by a mu2-CN-l igand through the Mo atoms and a mu2-S2- through two Fe atoms. The Mo. ..Mo and Fe...Fe(intercube) distances and the Fe-mu2-S-Fe angle are fo und at 5.267(4), 3.443(7) and 104.1(4)-degrees. The spectroscopic and electrochemical features of IV and V are discussed.