Synthesis characterization and reactivity of binary molybdenum sulfides: Tertiary oxo-disulfido molybdates and zirconium thiolates.

(Mo$\sb2$S$\sb9$) $\sp{2-}$ (6), and (Mo$\sb2$S$\sb6$) $\sp{2-}$ (3), were prepared from (Ph$\sb4$P)$\sb2$ (Mo$\sb2$S$\sb{10}$), by Na (BH$\sb4$) reduction or Ph$\sb3$P desulfurization respectively. (Mo$\sb2$S$\sb6$) $\sp{2-}$ showed sulfur vacancies and yielded (Mo$\sb2$S$\sb7$) $\sp{2-}$ (5), via the addition of 1 sulfur. (Mo$\sb2$(S)$\sb6$) $\sp{2-}$ features two tetrahedral $\{$Mo$\sp{\rm v}$(S)$\sb4\}$ units sharing an edge with Mo-S$\sb{\rm br}$ = 2.300(1) A. (Mo$\sb2$S$\sb9$) $\sp{2-}$ and (Mo$\sb2$S$\sb7$) $\sp{2-}$ are formally described as square-pyramidal (Mo$\sp{\rm iv}$(S)(S$\sb{\rm x}$)(Mo$\sp{\rm vi}$S$\sb4$) $\sp{2-}$ or (Mo$\sp{\rm v}$(S)(S$\sb{\rm x}$)(Mo$\sp{\rm v}$S$\sb4$)) $\sp{2-}$ (x = 2 or 4 for 5 and 6a respectively), where S$\sp{2-}$ occupies the apical position. Important bond lengths for the five-coordinate Mo(1) and the four-coordinate Mo(2) are: Mo(2)-S$\sb{\rm br}$, 2.283(3) for 5 and 2.254(5) for 6a; Mo(1)-S$\sb{\rm br}$, 2.322(4) for 5 and 2.3555(4) for 6a; Mo(1) = S, 2.105(3) for 6a and 2.103(3) A for 5. Oxidation of (MoO(S$\sb4$)$\sb2$) $\sp{2-}$ yielded (Mo$\sb2$O$\sb2$S$\sb{10}$) $\sp{2-}$ (8), and (Mo$\sb2$O$\sb2$S$\sb9$) $\sp{2-}$ (9), in (Et$\sb4$N)$\sb2$ (Mo$\sb2$O$\sb2$S$\sb{9.14}$). On warming in MeCN, the latter converted into syn- (($\eta\sp2$-S$\sb2$)(O)Mo($\mu$-S)$\sb2$Mo(O)(S$\sb4$)) $\sp{2-}$ (14). Reactivity studies on 9 afforded (Mo$\sb2$O$\sb2$S$\sb8$(SMe)) $\sp-$ (10), (Mo$\sb4$O$\sb4$S$\sb{18}$) $\sp{2-}$ (11), and (Mo$\sb2$O$\sb2$S$\sb8$Cl) $\sp-$ (12a). 8-12a feature pseudo pentagonal bipyramidal Mo(VI) ions. The axial sites are occupied by a terminal oxide and an intramolecularly, weakly interacting sulfur. The $\eta\sp2$-S$\sb2\sp{2-}$, Cl$\sp-$ and the bridging sulfur ligand occupy equatorial positions. Adjacent bipyramids share the bridging ligand: S$\sp{2-}$ in 9; $\eta\sp1,\eta\sp1$-S$\sb2\sp{2-}$ in 8; SMe$\sp-$ in 10; $\eta\sp2,\eta\sp1$-S$\sb2\sp{2-}$ in 12a; one $\eta\sp1,\eta\sp1$-S$\sb2\sp{2-}$ and two $\eta\sp2,\eta\sp1$-S$\sb2\sp{2-}$ ligands in 11. For 11: Mo-Mo = 3.606(1), 3.561(1); Mo-S = 2.386(4) and S-S = 2.043(5) for $\{$Mo-$\eta\sp2$S$\}$; Mo-S = 2.387(7), 2.457(5), 2.538(7) and S-S = 2.055(6) for $\{$Mo$\sb2$-($\mu$-$\eta\sp2,\eta\sp1$S$\sb2$)$\}$; Mo-S = 2.374(5), 2.380(4), 2.919(9) and S-S = 2.051(5) for the $\{$Mo$\sb2$-$\eta\sp2$S$\sb2\}$; Mo-S = 2.417(3) and S-S = 2.089(5) A for $\{$Mo$\sb2$-($\mu$-$\eta\sp1,\eta\sp1$S$\sb2$)$\}$. In 14, the involvement of S$\sb4\sp{2-}$ in d(Mo)-p(S) $\pi$ bonding is associated with the elongation of the trans Mo-S$\sb{\rm br}$ bonds by nearly 0.05 A. Comparative reactivity studies (MeCN, RT, 24h) for 14 and 15 toward DMAD were done. 14 produced (($\eta\sp1$S,$\eta\sp1$S-S$\sb2$C$\sb2$(COOMe)$\sb2$)$\sb2\{$syn-Mo$\sb2$(O)$\sb2$($\mu$-S)$\sb2\}$) $\sp{2-}$ (17), while 15 produced (trans($\eta\sp1$S,$\eta\sp1$C-S$\sb2$C$\sb2$(COOMe)$\sb2$)$\sb2\{$syn-Mo$\sb2$(O)$\sb2$($\mu$-S)$\sb2\}$) $\sp{2-}$ (18a), and the known cis-isomer (18b). 17 formed via ((S$\sb4$)($\eta\sp1$S,$\eta\sp1$C-S$\sb2$C$\sb2$(COOMe)$\sb2$)$\{$syn-Mo$\sb2$O$\sb2$S$\sb2\}$) $\sp{2-}$ (19). Prepared from the reaction of 12a with NiCl$\sb2$, (Ni(DMF)$\sb6$) (Mo$\sb2$O$\sb2$S$\sb8$Cl) $\sb2$, (12b), served as precursor of an effective alumina-supported HDS catalyst. At 1.7% Mo loading, 350$\sp\circ$C, TOF was 0.002 mol mol$\sp{-1}$s$\sp{1-}$, twice that of the commercial catalco catalyst. (Abstract shortened with permission of author.)Ph.D.Inorganic chemistryPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/128259/2/8907044.pd