TitleTroticene lithiation and platinum-catalyzed hydrosilylation using dimethylsilyl- troticene and ferrocene derivatives
NameTerrado, Rhyan Joseph (author), Sheridan, John (chair), Jäkle, Frieder (internal member), Lalancette, Roger (internal member), Schnatter, Wayne (outside member), Rutgers University, Graduate School - Newark,
DescriptionThe lithiation of troticene was studied. Monolithiation of troticene at 0 °C preferentially occurred at the cycloheptatrienyl (Cht) ligand,1,2 while monolithiation at room temperature preferentially occurred at the cyclopentadienyl (Cp) ligand. Dimethylsilyl-, trimethylstannyl-, diphenylphosphino-, and trimethylsilyl-derivatives were prepared in this manner. The monolithio-cycloheptatrienyl-troticene was found to be less stable at higher temperatures than the monolithio-cyclopentadienyl-troticene. Dilithiation of troticene was readily achieved using 2.5 equiv. n-butyllithium/TMEDA,3 and using an even greater excess of lithiating agent led to greater degrees of lithiation of up to 4 lithiums. Disubstituted Cp ligands are predominantly 1,3-disubstituted, while disubstituted Cht ligands are predominantly 1,4-disubstituted. Substituted troticene derivatives were also lithiated. Just like the 1-pot polylithiation, disubstituted Cp ligands are predominantly 1,3-disubstituted. However, disubstituted Cht ligands are either 1,4- or 1,3-disubstituted.
Dimethylsilyl-troticene derivatives were used in the preparation of troticene- based polymers/oligomers containing silylenevinylenephenylene-/thienylene-bridged metallocene units along with the appropriate model compounds. The regiochemical distributions obtained were consistent with those obtained by Jain and coworkers using dimethylsilyl ferrocene derivatives, with low molecular weights and no metal-metal interaction between the metallocene units.4,5
Hydrosilylation reactions of bis(dimethylsilyl)- ferrocene or troticene gave lower β(E)- to α- olefinic proton ratios compared to dimethylsilyl- ferrocene or troticene, the latter two giving regiochemical distributions consistent with those of 1,4-bis(dimethylsilyl)benzene or dimethylsilylbenzene. These results were consistent regardless of whether phenylacetylene, ethynyltoluene, or ethynylthiophene was used as the alkyne.
A comparison between the hydrosilylation mono-β(E)- and mono-α- adducts of 1,4-bis(dimethylsilyl)benzene and 1,1’-bis(dimethylsilyl)ferrocene with phenylacetylene was done. The hydrosilylation reactions of the mono-β(E)- adducts of both compounds as well as the mono-α- adduct of 1,4-bis(dimethylsilyl)benzene were all consistent with each other, preferring a β(E)- configuration in the hydrosilylation of the second dimethylsilyl-moiety. In contrast, the mono-α- adduct of 1,1’-bis(dimethylsilyl)ferrocene preferred an α- configuration in the hydrosilylation of the second dimethylsilyl-moiety. In addition, the mono-α- adduct of 1,1’-bis(dimethylsilyl)ferrocene was more readily converted into the bis-adducts than the mono-β(E)- adduct. These factors led to an increased amount of α-olefinic protons in hydrosilylation reactions of 1,1’-bis(dimethylsilyl)ferrocene.
NoteIncludes bibliographical references (p. 236-254)
Noteby Rhyan Josephy Soriano Terrado
CollectionGraduate School - Newark Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.