Syntheses of Metal Dithiolene Complexes from Thiometalates by Induced Internal Redox Reactions

A variety of new and known transition metal dithiolene complexes has been synthesized from thiometalates via
induced internal electron-transfer reactions. Treating MS42- (M = Mo, W) with stoichiometric amounts of bis(trifluoromethyl)-1,2-dithiete ((CF3)2C2S2) results in rapid formation of the respective tris(dithiolene) complexes
M(tfd)32- (tfd = [(CF3)2C2S2]2-). These complexes are isostructural and adopt twisted trigonal prismatic
coordination (ca. 18° from a perfect trigonal prism). Crystal data:  Mo(tfd)32-, monoclinic, space group C2/c,
with a = 18.905(4) Å, b = 13.732(3) Å, c = 17.101(3) Å, β = 110.29(3)°, and Z = 4; W(tfd)32-, monoclinic,
space group C2/c, with a = 18.933(4) Å, b = 13.728(3) Å, c = 17.096(3) Å, β = 110.26(3)°, and Z = 4. In
contrast, Mo(tfd)3 (synthesized as reported previously) has nearly perfect trigonal prismatic coordination. Crystal
data:  hexagonal, space group P63/m, with a = 9.6795(14) Å, b = 9.6795(14) Å, c = 13.951(3) Å, and Z = 2.
Treating WOS32- and MoO2S22- with (CF3)2C2S2 results in the respective MO(tfd)22- complexes. These two
complexes are isostructural and adopt square pyramidal coordination with four sulfur atoms forming the base and
oxygen at the apex. Crystal data:  MoO(tfd)22-, monoclinic, space group P21/n, with a = 12.184(2) Å, b =
18.627(4) Å, c = 15.482(3) Å, β = 91.06(3)°, and Z = 4; WO(tfd)22-, monoclinic, space group P21/n, with a =
12.200(2) Å, b = 18.630(4) Å, c = 15.463(3) Å, β = 91.02(3)°, and Z = 4. On the basis of spectroscopic
evidence, the product from the reaction of ReS4- with (CF3)2C2S2 is proposed to be {Re[S2C2(CF3)2][S3C2(CF3)2]2}-.
Influences of the nature of the oxidant on the ease with which thiometalates undergo induced internal electron-transfer reactions are discussed.