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A silsesquioxane cage polymer functionalized with eight chloropropyl arms (1, T8-PrCl) reacted with 2,2′-dipyridiylamine (DPA) to afford a new derivative with eight pendant linear chains (2, T8-Pr-DPA). Further reaction with [Mo(η3-C3H5)Br(CO)2(NCMe)2] afforded another derivative containing three molybdenum units (3, T8-Pr-DPA-Mo), after substitution of the two nitrile ligands in each complex. These are the first silsesquioxane species containing DPA and the Mo(η3-C3H5)Br(CO)2 fragment. The three materials were characterized by 1H, 13C, 29Si, and 95Mo NMR, FTIR, XRD, and elemental analysis, and T8-PrCl (1) was also structurally characterized by single-crystal X-ray diffraction. It was identified as a low-temperature polymorph of this material. Elemental analysis indicated that all Cl atoms in the parent material T8-PrCl (1) were substituted by the deprotonated DPA group in T8-Pr-DPA (2). However, only three [Mo(η3-C3H5)Br(CO)2(DPA)] units were detected in T8-Pr-DPA-Mo (3). A comprehensive NMR study, compl...

Complex fac-[Re{κ3-H(µ-H)2B(timMe)}(CO)3] (1) (timMe = 2-mercapto-1-methylimidazolyl) promptly reacts with the neutral substrates PPh3, tBuNC and EtOOCCH2NC yielding fac-[Re{κ2-H2(µ-H)B(timMe)}(L)(CO)3] (L = PPh3(2), (tBuNC) (3), (EtOOCCH2NC) (4)). Complexes 2−4 have been fully characterized, including by variable-temperature NMR studies and X-ray diffraction analysis in the case of 2. Unlike 1, complexes 2−4 are fluxional in solution undergoing a dynamic process that accounts for the magnetic equivalence of all the B−H hydrogen atoms at room temperature. Compounds 1 and 2 were studied by DFT methods to explain the different solution behavior of the complexes anchored by (κ2-H,S) and (κ3-H,H′,S) soft scorpionates.

New Mo(II) diimine derivatives of [Mo(η3-allyl)X(CO)2(CH3CN)2] (allyl = C3H5 and C5H5O; X = Cl, Br) were prepared, and [Mo(η3-C3H5)Cl(CO)2(BIAN)] (BIAN = 1,4-(4-chloro)phenyl-2,3-naphthalenediazabutadiene) (7) was structurally characterized by single-crystal X-ray diffraction. This complex adopted an equatorial−axial arrangement of the bidentate ligand (axial isomer), in contrast with the precursors, found as the equatorial isomer in the solid and fluxional in solution. The new complexes of the type [Mo(η3-allyl)X(CO)2(N−N)] (N−N is a bidentate chelating dinitrogen ligand) were tested for the catalytic epoxidation of cyclooctene using tert-butyl hydroperoxide as oxidant. All catalytic systems were 100% selective toward epoxide formation. While their turnover frequencies paralleled those of related Mo(II) carbonyl compounds or Mo(VI) compounds bearing similar N-donor ligands, they exhibited similar olefin conversions in consecutive catalytic runs. The acetonitrile precursors were generally more active than...