ACTIVATION OF ETHERS AND SULFIDES BY ORGANOLANTHANIDE HYDRIDES - MOLECULAR-STRUCTURES OF (CP-ASTERISK(2)Y)(2)(MU-OCH(2)CH(2)0)(THF)(2) AND (CP-ASTERISK-CE-2)(2)(MU-O)(THF)(2)

Dialkyl ethers, ROR', are cleaved by hydrides (Cp*(2)LnH)(2) (Ln = Y 1a, La 1b, Ce 1c) to form alkoxides Cp*(2)LnOR (2), Cp*(2)LnOR', R'H, and RH. The extent to which either of the C-O bonds of asymmetric substituted dialkyl ethers ROR' is attacked strongly depends on the alkyl substituents but is relatively insensitive to the nature of the metal. Ring opening is observed with THF or 1,4-dioxane leading to Cp*(2)YO(n)Bu (6a) and (Cp*Y-2)(2)(mu-OCH2CH2O)(THF)(2) (8), respectively. The molecular structure of 8 was determined by X-ray diffraction. Space group Pbcn had unit cell parameters a = 21.7483(12) Angstrom, b = 14.2806(12) Angstrom, c = 16.726(2) Angstrom and Z = 4. Least-squares refinement based on 4163 reflections converged to R = 0.063. Unsaturated ethers, vinyl ethyl ether and allyl ethyl ether, are cleaved instantaneously by 1a to form Cp*(2)YOEt. Also, the C-O bonds of Cp*(2)LnOEt are attacked by (Cp*(2)LnH)(2) to give the oxo bridged compound (Cp*(2)Ln)(2)(mu-O) and ethane. The molecular structure of the THF adduct of the cerium analogue (Cp*Ce-2)(2)(mu-O)(THF)(2) (12) was determined by X-ray diffraction: spacegroup P ($) over bar 1 had unit cell parameters a = 13.399(2) Angstrom, b = 14.864(4) Angstrom, c = 15.812(6) Angstrom, alpha = 70.75(2)degrees, beta = 85.15(2)degrees, gamma = 63.78(2)degrees, and Z = 2. Least-squares refinement based on 6294 reflections converged to R = 0.038. In contrast to ethers, organic sulfides RSR' are metallated by 1a to produce products Cp*(2)YCH(2)SMe (13, R = R' = Me), Cp*(2)YCR(SMe)Ph (15, R = Me, R' = Ph), CP*Y-2(SC4H3) (18, RR' = CH=CHCH=CH), and dihydrogen. Only Et(2)S underwent C-S cleavage to form Cp*(2)YSEt (16) and ethane. Reaction of 1a with allyl methyl sulfide is not clean, but 1a is a modest catalyst for the hydrogenation of allyl methyl sulfide.