Reactions Of Cp2TiCl2 (CP = eta(5)-cyclopentadienide) with 2 or 1 equiv of hybrid P-S ligands (L), (CH3)(2)P(CH2)(n)S-(n = 2, dmpet; n = 3, dmppt), produced new dicyclopentadienyltitanium(IV) complexes with L, CP2Ti(L-kappa(2)S)(2) (1, L = dmpet; 2, L dmppt) and [Cp2Ti(L-kappa(2)S,P)]BPh4 (3, L = dmpet; 4, L = dmppt). The Ti(III) complexes, Cp2Ti(L-kappa(2)S,P) (5, L = dmpet; 6, L = dmppt), were prepared by the reaction Of Cp2Ti(eta(3)-C3H5) with 1 equiv of L. The structures of complexes 1-6 were confirmed by X-ray diffraction analyses. It was found that complexes 3 and 5 were isostructural around Ti(IV) and Ti(III) centers: the Ti(IV)-S bond length in 3 (2.3498(9) Angstrom) is shorter by 0.14 Angstrom than Ti(III)-S in 5 (2.4877(7) Angstrom), while Ti(IV)-P (2.534(l) Angstrom) was merely 0.05 Angstrom shorter than Ti(III)-P (2.5844(7) Angstrom). The redox potential between 3 and 5 in acetonitrile was -1.14 V vs the ferricinium/ferrocene couple. A heterobimetallic complex that has the frame of complex 1, [Cp2Ti(dmpet)(2)Cu]PF6 (7), was also isolated and structurally characterized: the Ti-Cu distance (2.95(1) Angstrom) was shorter than that in [Cp2Ti(SC2H4PPh2)(2)Cu]BF4, previously reported by White and Stephan. Structural characterization was also carried out for Cp*Ti(dmpet-kappaS)(2)(dmpet-kappa(2)S,P) (8) and CpTiCl2(dMppt-kappa(2)S,P) (9), which were obtained by the reactions of Cp*(or Cp)TiCl3 (CP* = eta(5)-C5Me5-) with n equiv (n = 1-3) of L. The mutual site-exchange reaction between phosphorus atoms on a coordinated dmpet in the kappa(2)S,P mode and on two other coordinated dmpet's in the kappaS mode within complex 8 was analyzed by the variable-temperature P-31{H-1} dynamic NMR method. The kinetic parameters for this process, k(ex)(298) = 1.9 X 10(5) s(-1), DeltaH(double dagger) = 48 kJ mol(-1), and DeltaS(double dagger) = 17 J mol(-1) K-1, as well as the rather long Ti(IV)-P distance (2.652(1) Angstrom), indicate the fluxional nature of the coordination geometry in complex 8.