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  1. Abstract

    3,3′,5,5′‐Tetra‐tert‐butyl‐2′‐sulfanyl[1,1′‐biphenyl]‐2‐ol (H2[tBu4OS]) was prepared in 24 % yield overall from the analogous biphenol using standard techniques. Addition of H2[tBu4OS] to Mo(NAr)(CHCMe2Ph)(2,5‐dimethylpyrrolide)2led to formation of Mo(NAr)(CHCMe2Ph)[tBu4OS], which was trapped with PMe3to give Mo(NAr)(CHCMe2Ph)[tBu4OS](PMe3) (1(PMe3)). An X‐ray crystallographic study of1(PMe3) revealed that two structurally distinct square pyramidal molecules are present in which the alkylidene ligand occupies the apical position in each. Both1(PMe3)Aand1(PMe3)Bare disordered. Mo(NAd)(CHCMe2Ph)(tBu4OS)(PMe3) (2(PMe3); Ad=1‐adamantyl) and W(NAr)(CHCMe2Ph)(tBu4OS)(PMe3) (3(PMe3)) were prepared using analogous approaches.1(PMe3) reacts with ethylene (1 atm) in benzene within 45 minutes to give an ethylene complex Mo(NAr)(tBu4OS)(C2H4) (4) that is isolable and relatively stable toward loss of ethylene below 60 °C. An X‐ray study shows that the bond distances and angles for the ethylene ligand in4are like those found for bisalkoxide ethylene complexes of the same general type. Complex1(PMe3) in the presence of one equivalent of B(C6F5)3catalyzes the homocoupling of 1‐decene, allyltrimethylsilane, and allylboronic acid pinacol ester at ambient temperature.1(PMe3),2(PMe3), and3(PMe3) all catalyze the ROMP ofracendo,exo‐5,6‐dicarbomethoxynorbornene (rac‐DCMNBE) in the presence of B(C6F5)3, but the polyDCMNBE that is formed has a random structure.

     
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  2. Abstract

    Multinuclear solid‐state NMR studies of Cp*2Sc−R (Cp*=pentamethylcyclopentadienyl; R=Me, Ph, Et) and DFT calculations show that the Sc−Et complex contains a β‐CH agostic interaction. The static central transition45Sc NMR spectra show that the quadrupolar coupling constants (Cq) follow the trend of Ph≈Me>Et, indicating that the Sc−R bond is different in Cp*2Sc−Et compared to the methyl and phenyl complexes. Analysis of the chemical shift tensor (CST) shows that the deshielding experienced by Cβ in Sc−CH2CH3is related to coupling between the filled σC‐Corbital and the vacantorbital.

     
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  3. Abstract

    Multinuclear solid‐state NMR studies of Cp*2Sc−R (Cp*=pentamethylcyclopentadienyl; R=Me, Ph, Et) and DFT calculations show that the Sc−Et complex contains a β‐CH agostic interaction. The static central transition45Sc NMR spectra show that the quadrupolar coupling constants (Cq) follow the trend of Ph≈Me>Et, indicating that the Sc−R bond is different in Cp*2Sc−Et compared to the methyl and phenyl complexes. Analysis of the chemical shift tensor (CST) shows that the deshielding experienced by Cβ in Sc−CH2CH3is related to coupling between the filled σC‐Corbital and the vacantorbital.

     
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