Synthesis, structure, and reactivity studies of novel organometallic and inorganic lanthanide complexes

The first part of this dissertation describes the use of alkoxide and aryloxide ligands as ancillary ligands to stabilize reactive cyclopentadienyl-free trivalent yttrium and lanthanide alkyl complexes. A variety of synthetic approaches to alkyl alkoxide and aryloxide complexes of yttrium and the lanthanide metals were explored and the most successful syntheses were found to involve the direct reaction of metal trichlorides with alkyl lithium and lithium alkoxide reagents. This method led to the synthesis of three fully characterizable anionic "ate" complexes, (({dollar}rm Mesb3Si)sb2CHrbracksb2Y(mu{dollar}-{dollar}rm OCMesb3)sb2Li(THF), {lcub}(Mesb3SiCHsb2)sb2Y(OCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-{dollar}rm 2,6)sb2{rcub}{lcub}lbrack(THF)sb3Lirbracksb2Cl{rcub},{dollar} and {dollar}rm {lcub}(Mesb3SiCHsb2)sb2Lu(OCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-{dollar}rm 2,6)sb2{rcub}lbrack(THF)sb4Lirbrack(THF)sb2{dollar} as well as two neutral complexes, {dollar}rm (Mesb3SiCHsb2)sb2Y(OCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-2,6)(THF){dollar}sb2{dollar} and {dollar}rm(Mesb3SiCHsb2)sb2Y(OCsb6Hsb3sp{lcub}t{rcub} Busb2{dollar}-2,4,6)(THF).; The neutral complex {dollar}rm (Mesb3SiCHsb2)sb2Y(OCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-2,6)(THF){dollar}sb2{dollar} proved to be the most reactive of these complexes and was selected for detailed reactivity studies. The reactivity of this compound with common substrates was examined and compared to the reactivity of cyclopentadienide-containing yttrium and lanthanide alkyl complexes. {dollar}rm (Mesb3SiCHsb2)sb2Y(OCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-2,6)(THF){dollar}sb2{dollar} was found to polymerize {dollar}varepsilon{dollar}-caprolactone and ethylene and to exhibit metallation reactivity with pyridine, toluene, phenylacetylene, {dollar}sp{lcub}rm i{rcub}{dollar}PrCN, PhCN, PhCH{dollar}sb2{dollar}CN, and CH{dollar}sb3{dollar}CN. Except for the polymers, isolation of the resulting products has proven difficult due to the presence of complicated mixtures of products. Insertion of common unsaturated substrates, {dollar}sp{lcub}rm t{rcub}{dollar}BuNC, CO, CO{dollar}sb2,{dollar} and PhNCE (E = O, S), into the Y-alkyl bond was also observed with {dollar}rm (Mesb3SiCHsb2)sb2Y(OCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-2,6)(THF){dollar}sb2.{dollar} Characterization of the products of these reactions has led to the identification of several by-products: {dollar}rmlbrack(THF)LiOCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-{dollar}rm2,6rbracksb2, Y(OCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-{dollar}rm2,6)sb3(THF)sb3, HOCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-2,6, (O=C{dollar}rmsb6Hsb2sp{lcub}t{rcub}Busb2{dollar}-2,6) {dollar}sb2.{dollar}; The second part of this dissertation describes the isolation and crystallographic characterization of the first molecular divalent complex of thulium and its subsequent reactivity. Traditionally, molecular divalent lanthanide chemistry involved only the three metals, Sm(II), Eu(II), and Yb(II). Isolation of {dollar}rm TmIsb2(DME)sb3,{dollar} (DME = dimethoxyethane) showed that Tm(II) was also accessible in molecular species. The strong reduction potential of divalent thulium ({dollar}-{dollar}2.3 V vs. NHE) has been observed in the reactivity of thulium diiodide, which rapidly oxidizes to trivalent products upon the addition of common substrates, including pyridine, 2,2{dollar}spprime{dollar}-bipyridine, {dollar}rm LiCHsb2SiMesb3, LiCH(SiMesb3)sb2, LiOCMesb3, KOCsb6Hsb3sp{lcub}t{rcub}Busb2{dollar}-2,6, KN(SiMe{dollar}sb3)sb2,{dollar} and KC{dollar}sb5{dollar}Me{dollar}sb5.{dollar} TmI{dollar}sb2{dollar}(DME){dollar}sb2{dollar} reacts with hexamethylphosphoramide (HMPA) in DME, forming the pale yellow insoluble, TmI{dollar}sb3{dollar}(HMPA){dollar}sb4,{dollar} which can be recrystallized as either {dollar}rm {lcub}lbrack TmIsb2(HMPA)sb4sp+rbracklbr...