Synthesis and Chemical and Electrochemical Characterization of Fe−S Carbonyl Clusters. X-ray Crystal Structures of [N(PPh3)2]2[Fe5S2(CO)14] and [N(PPh3)2]2[Fe6S6(CO)12]

A reinvestigation of the redox behavior of the [Fe3(μ3-S)(CO)9]2- dianion led to the isolation and characterization of the new [Fe5S2(CO)14]2-, as well as the known [Fe6S6(CO)12]2- dianion. As a corollary, new syntheses of the [Fe3S(CO)9]2- dianion are also reported. The [Fe5S2(CO)14]2- dianion has been obtained by oxidative condensation of [Fe3S(CO)9]2- induced by tropylium and Ag(I) salts or SCl2, or more straightforwardly through the reaction of [Fe4(CO)13]2- with SCl2. The [Fe6S6(CO)12]2- dianion has been isolated as a byproduct of the synthesis of [Fe3S(CO)9]2- and [Fe5S2(CO)14]2- or by reaction of [Fe4(CO)13]2- with elemental sulfur. The structures of [N(PPh3)2]2[Fe5S2(CO)14] and [N(PPh3)2]2[Fe6S6(CO)12] were determined by single-crystal X-ray diffraction analyses. Crystal data:  for [N(PPh3)2]2[Fe5S2(CO)14], monoclinic, space group P21/c (No. 14), a = 24.060(5), b = 14.355(6), c = 23.898(13) A, β = 90.42(3)°, Z = 4; for [N(PPh3)2]2[Fe6S6(CO)12], monoclinic, space group C2/c (No. 15), a = 34.424(4),...