Syntheses and Characterization of Two Diiron Dithiolate Complexes Containing 4-Dimethylaminopyridine

Two diiron dithiolate complexes, (mu-pdt)Fe(2)(CO)(5)(C(7)H(10)N(2)) 3 and (mu-edt)-Fe(2)(CO)(5)(C(7)H(10)N(2)) 4 (pdt = -S(CH(2))(3)S-, edt = -S(CH(2))(2)S-), have been synthesized and characterized by single-crystal X-ray diffraction. Complex 3 crystallizes in the monoclinic system, space group P2(1)/c with a = 10.168(4), b = 11.816(4), c = 16.595(7) angstrom and beta = 95.195(6)degrees; and complex 4 crystallizes in the orthorhombic system, space group P2(1)2(1)2(1) with a = 9.317(3), b = 11.898(4), c = 34.006(10) angstrom. The distances of Fe(1)-Fe(2) are 2.5058(9) angstrom in 3 and 2.4942(10) angstrom in 4, falling in the normal range of Fe-Fe bond length (2.49 similar to 2.57 angstrom). The cyclic voltammograms show that 3 and 4 display irreversible reduction peaks (Fe(I)Fe(I)/ Fe(I)Fe(0)) at -1.717 V and -1.673 V vs. Ag/AgCl, respectively. With different acids, complex 3 has distinguishable behavior, two protonations in addition of HBF(4)-Et(2)O and single protonation besides HOAc-CH(3)CN, and complex 4 has a similar action to 3 with HOAc-CH(3)CN for a semblable structure.