Bis(Cyclopentadienyl)Titanium Complexes of Naphthalene−1,8-Dithiolates, Biphenyl 2,2‘-Dithiolates, and Related Ligands

Titanocene 1,8-dithiolato−naphthalene and titanocene 2,2‘-dithiolato biphenyl are produced by the reaction of naphtho[1,8-cd]-1,2-dithiole [or the biphenyl] with titanocene dicarbonyl (Ti(II)) in toluene at room temperature. The pro-ligands 2,7-di(tert-butyl)naphtho[1,8-cd]-1,2-dithiole, 5,6-dihydroacenaphtho[5,6-cd]-1,2-dithiole, 4,5-dithioacephenanthrylene, and 13,14-dithiapicene have been used in similar reactions with titanocene dicarbonyl to investigate
the effect of steric bulk and of varying the naphthalene backbone on the final complex. The resulting Cp2TiS2Ar
complexes (Ar = naphthalene) have been shown by temperature-dependent 1H NMR spectroscopy to exist in
solution in an envelope conformation with the six-membered TiS2C3 rings undergoing inversion on the NMR time
scale while the similar Cp2TiS2Ar complexes (Ar = biphenyl, binaphthalene) interconvert more rapidly. Titanocene
2,2‘-disulfinato biphenyl has been synthesized by the salt elimination reaction of titanocene dichloride (Ti(IV)) and
the disodium salt of biphenyl 2,2‘-disulfinic acid. Finally, the effect of using pro-ligands where the sulfur atoms
have been mono- or di-oxidized has been studied, and an interesting oxygen elimination reaction is observed for
the SO fragments but not for the SO2 groups. All complexes have been characterized spectroscopically and
seven X-ray structures are reported.