| For the past 30 years, the organometallic chemistry of yttrium and the lanthanides has been dominated by the bis (pentamethylcyclopentadienyl) ancillary ligand framework. In order to advance the chemistry of these metals, new ligand environments were sought. The research presented here demonstrates new coordination and reaction chemistry achieved by the attachment of an alkene substituent to the tetramethylcyclopentadienyl ligand and by utilizing cyclopentadienyl alternatives which incorporate N and O donor atoms.; Chapter 1 describes the synthesis of a new cyclopentadiene, (C5 Me4H)SiMe2(CH2CH=CH2), which was conveniently prepared from readily available starting materials. (C 5Me4H)SiMe2(CH2CH=CH2) reacts with Y(CH2SiMe3)3(THF)2 to form a monocyclopentadienyl yttrium dialkyl complex, [(C5Me4)SiMe 2(CH2CH=CH2)]Y(CH2SiMe3) 2(THF)2, a type of compound rarely isolated for yttrium and the lanthanide. Unexpectedly, [(C5Me4)SiMe2(CH 2CH=CH2)]Y(CH2SiMe3)2(THF) 2 undergoes hydrocarbon elimination to form a complex containing a trianionic cyclopentadienyl ligand, {lcub}[(C5Me4)SiMe 2(C3H3)]Y(L){rcub}2 (L = THF, DME). This reaction demonstrates that powerful metalations can occur in metallocene environments of the type used in olefin polymerization when tethered olefins are placed in the proximity of the metal center.; Chapter 2 presents the synthesis, structure, and reactivity of [(C 5Me4)SiMe2(CH2CH=CH2)] 2Y(η3-C3H5), a complex synthesized to study metalolefin chemistry. In the presence of excess Al2Me 6, the olefins remain ancillary and {lcub}[(C5Me4)SiMe 2(CH2CH=CH2)]2Y(AlMe4){rcub} 2 is formed. However, in the presence of H2, the tethered olefins undergo hydrogenation. Evidence for an yttrium-alkene interaction was obtained through low temperature NMR studies.; Chapter 3 describes the preparation of divalent lanthanide complexes [(C5Me4)SiMe2(CH2CH=CH2)] 2Ln (Ln = Sm, Eu, Yb). The X-ray crystal structure of [(C5Me 4)SiMe2(CH2CH=CH2)]2Eu established that the tethered olefins coordinate to the metal center. The reduction of AgBPh4 was examined to set up a competition between [BPh4 ]− and the tethered alkene for coordination to the metal. The structure of [(C5Me4)SiMe2(CH 2CH=CH2)]2Sm[BPh4] shows that alkenes can bind preferentially to tetraphenylborate.; Chapters 4 and 5 describe the use of cyclopentadienyl alternative anions derived from 2,3-dimethylindole, [Me2C8H4N] − (DMI), and Zr2(OiPr)8(HO iPr)2, [Zr2(OiPr)9] (DZNI). DMI and DZNI were chosen as due to the variation in binding modes possible with the lanthanides. The coordination chemistry of {lcub}[Zr2(O iPr)9]YCl2{rcub}2, (C10H 10N)2Sm(THF)4, (C10H10N) 3Y(THF)2, (C5Me5)2Sm(C 10H10N) and (C5Me5)2Y(... |
