A series of bidentate amidate ligands with variable groups R' and R" abbreviated by [R"(NO)R'] and adamantyl substituted tetradentate amidate ligands abbreviated by Ad[0₂N₂] were utilized as ancillaries for Ti, Zr, and Hf. Protonolysis routes into homoleptic amidate complexes, tris(amidate) mono(amido), bis(amidate) bis(amido), and bis(amidate) dibenzyl complexes are high yielding when performed with tetrakis(amido) and tetrabenzyl group 4 starting materials. Many of these complexes have been characterized in both the solid-state and in the solution phase, where in the latter case these complexes are fluxional and undergo exchange processes. Multiple geometric isomers are possible with the mixed N,0 chelate provided by the amidate ligands, and geometric isomerization of bis(amidate) bis(amido) complexes has been examined through X-ray crystallographic and density functional theory (DFT) calculations. Isomerization is dictated largely by the steric bulk present at the N of the amidate ligands, and is proposed to proceed through a K²-K¹-K² ligand isomerization mechanism, which is supported by crystallographic evidence of K¹-bound amidate ligands. The amidate ligand system binds to these metals in a largely electrostatic fashion, with poor orbital overlap, generating highly electrophilic metal centers. The bis(amidate) dibenzyl complexes of Zr and Hf are reactive towards insertion, abstraction, and protonolysis. Insertion of isocyanides into the Zr-C bonds of [DMP(NO) tBu]₂Zr(CH₂Ph₂ results in the formation of ƞ₂-iminoacyl complexes, which can either undergo thermally induced C=C coupling to generate an enediamido complex (aryl isocyanides), or rearrange to generate a bis(amidate) bis(vinylamido) complex (alkyl isocyanides). Benzyl abstraction to generate cationic Zr bis(amidate) benzyl complexes is also possible through reaction with [Ph₃C][B(C₆F₅)4] or B(C₆F₅)₃ Terminal imido complexes with novel pyramidal geometries are generated through protonolysis of bis(amidate) bis(amido) Ti and Zr complexes with primary aryl amines. DFT calculations demonstrate the existence of a Zr⁻₌N triple bond for these complexes. Dimeric imido complexes have been characterized in the solid state, but are not maintained in solution. Cycloaddition reactions of the terminal Zr imido complexes with C=0 bonds result in the formation of proposed oxo complexes and organic metathesis products. Catalytic aminoalkene cyclohydroamination has also been realized with these complexes, generating N-heterocyclic products. A series of kinetic and labeling studies support an imido-cycloaddition mechanism for catalytic cyclohydroamination of primary aminoalkenes with neutral bis(amidate) Ti and Zr precatalysts. The intermediate Ti imido complex, K²-[Dipp(NO)tBu-K¹_[DiPP(No) tBu]Ti=NCH₂CPh₂CH₂CH=CH₂(NHMe₂), has been isolated and characterized in the solid-state and in solution. Amine stabilized imido complexes of this type are invoked as the resting state for the catalytic reaction, and solution phase data support a chair-like geometry, where the alkene is coordinated to the metal center. A diastereoselectivity study supports this proposed solution structure. Eyring and Arrhenius parameters, as well as isolation of a 7-coordinate model imido complex, support a seven-coordinate transition state for the rate-determining metallacycle protonolysis reaction. In contrast, secondary aminoalkene hydroamination catalysis with cationic Zr benzyl complexes is proposed to proceed through a σ-bond insertion mechanism. Proton loss from cationic Zr amido complexes to generate imido species is proposed with primary aminoalkenes, and the resultant neutral imido complexes can catalyze the cyclization of these substrates by the aforementioned imido-cycloaddition mechanism. The ability of the amidate ligand system to promote both mechanisms is unique in the field of alkene hydroamination catalysis.

This thesis concerns the new amine-substituted cyclopentadiene and indene ligands C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H which can co-ordinate to a metal through all five carbon atoms of the five-membered ring (η(^5)) and/ or through the nitrogen (σ). Chapter 1 reviews the recent literature concerning Lewis-base functionalised cyclopentadienyl and indenyl ligands and their compounds with s-, p-, d- and f-block metals. Chapter 2 contains a brief review of possible synthetic routes to amine-substituted cyclopentadienyl and indenyl ligands with some examples from the recent literature, and a detailed account of the synthesis of C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H. The amino alcohol (^t)BuNH(CH(_2))(_3) OH was synthesised by the conjugate addition of (^t)BuNH(_2) to ethyl acrylate and reduction of the product ester (^t)BuNH(CH(_2))(_2)C0(_2)Et using LiAIH(_4). (^t)BuNH(CH(_2))(_3)OH was converted into (^t)BuNH(CH(_2))(_3)Br.HBr and (^t)BuNH(CH(_2)(_3)Cl.HCl by reaction with HBr or SOCI(_2). Reaction between (^t)BuNH(CH(_2))(_3)C1.HC1 and two equivalents of Na(C(_5)H(_5)) gave C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H in good yield. Treatment of (^1)BuNH(CH(_2))(_3)C1.HC1 with excess NaOH followed by reaction with Li(C(_9)H(_7)) gave C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H, also in good yield. Chapter 3 describes the synthesis of various main group and iron compounds of C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H. Lithium salts Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H], Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)]Li, Li[C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)H] and Li[C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)]Li were prepared for use as reactive intermediates and Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H] was characterised as its THF-adduct by (^t)H NMR spectroscopy. The silyl derivatives (Me(_3)Si)C(_5)H(_4)(CH(_2))(_3)NH(^t)Bu and (Me(_3)Si)C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)SiMe(_3) were synthesised and characterised by NMR spectroscopy, and (Me(_3)Si)C(_9)H(_6)(CH(_6))(_3)N((^t)Bu)H and (Me(_3)Si)C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)(SiMe(_3)) were also synthesised. The anune-substituted ferrocene Fe{η(^5)-C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H}(_2) was synthesised and oxidised to the corresponding ferricenium ion which was isolated as its PF(_6)(^-) salt. Exploratory work was carried out into the preparation of heterobimetallic species by reaction between Fe{η(^5)-C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H}(_2) and MX(_2) (M = Co, Ni, X = CI, M = Mn, X = Br). The substituted bis(indenyl) iron(II) complex Fe{η(^5)-C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)H}(_2) was also synthesised. Chapter 4 is an account of the chemistry of {η(^5) :σ-C(_5)H(_4) (CH(_2))(_3)N(^t)Bu}Ti(NMe(-2))(_2) which was synthesised by an aminolysis reaction between C(_5)H(_5)(CH(_2))(_3)NH(^t)Bu and Ti(NMe(_2))(_4) Reaction between this compound and various weak acids gave a range of new compounds including{η(^5):σ-C(_5)H(_4)(CH(_2))(-3)N(^t)Bu} Ti(O(^t)Pr)(_2), {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu)(_2), {η(^5):σC, {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(C(_5)H(_5))(NMe(_2)) , {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(SnBu(_3))(_z) and the imido-bridged dimer [{η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(NHPh)](_2)(µ-NPh)2, the X-ray structure of which is reported. Chapter 5 describes the experimental procedures used, and chapter 6 gives lists of characterising data for each compound. Appendix A gives details of the methods used for magnetic susceptibility determinations; appendix B lists X-ray crystallographic data for [ {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(NHPh)](_2)(µ-NPh)(_2) and appendix C lists departmental colloquia attended.

A series of bidentate amidate ligands with variable groups R' and R" abbreviated by [R"(NO)R'] and adamantyl substituted tetradentate amidate ligands abbreviated by Ad[0₂N₂] were utilized as ancillaries for Ti, Zr, and Hf. Protonolysis routes into homoleptic amidate complexes, tris(amidate) mono(amido), bis(amidate) bis(amido), and bis(amidate) dibenzyl complexes are high yielding when performed with tetrakis(amido) and tetrabenzyl group 4 starting materials. Many of these complexes have been characterized in both the solid-state and in the solution phase, where in the latter case these complexes are fluxional and undergo exchange processes. Multiple geometric isomers are possible with the mixed N,0 chelate provided by the amidate ligands, and geometric isomerization of bis(amidate) bis(amido) complexes has been examined through X-ray crystallographic and density functional theory (DFT) calculations. Isomerization is dictated largely by the steric bulk present at the N of the amidate ligands, and is proposed to proceed through a K²-K¹-K² ligand isomerization mechanism, which is supported by crystallographic evidence of K¹-bound amidate ligands. The amidate ligand system binds to these metals in a largely electrostatic fashion, with poor orbital overlap, generating highly electrophilic metal centers. The bis(amidate) dibenzyl complexes of Zr and Hf are reactive towards insertion, abstraction, and protonolysis. Insertion of isocyanides into the Zr-C bonds of [DMP(NO) tBu]₂Zr(CH₂Ph₂ results in the formation of ƞ₂-iminoacyl complexes, which can either undergo thermally induced C=C coupling to generate an enediamido complex (aryl isocyanides), or rearrange to generate a bis(amidate) bis(vinylamido) complex (alkyl isocyanides). Benzyl abstraction to generate cationic Zr bis(amidate) benzyl complexes is also possible through reaction with [Ph₃C][B(C₆F₅)4] or B(C₆F₅)₃ Terminal imido complexes with novel pyramidal geometries are generated through protonolysis of bis(amidate) bis(amido) Ti and Zr complexes with primary aryl amines. DFT calculations demonstrate the existence of a Zr⁻₌N triple bond for these complexes. Dimeric imido complexes have been characterized in the solid state, but are not maintained in solution. Cycloaddition reactions of the terminal Zr imido complexes with C=0 bonds result in the formation of proposed oxo complexes and organic metathesis products. Catalytic aminoalkene cyclohydroamination has also been realized with these complexes, generating N-heterocyclic products. A series of kinetic and labeling studies support an imido-cycloaddition mechanism for catalytic cyclohydroamination of primary aminoalkenes with neutral bis(amidate) Ti and Zr precatalysts. The intermediate Ti imido complex, K²-[Dipp(NO)tBu-K¹_[DiPP(No) tBu]Ti=NCH₂CPh₂CH₂CH=CH₂(NHMe₂), has been isolated and characterized in the solid-state and in solution. Amine stabilized imido complexes of this type are invoked as the resting state for the catalytic reaction, and solution phase data support a chair-like geometry, where the alkene is coordinated to the metal center. A diastereoselectivity study supports this proposed solution structure. Eyring and Arrhenius parameters, as well as isolation of a 7-coordinate model imido complex, support a seven-coordinate transition state for the rate-determining metallacycle protonolysis reaction. In contrast, secondary aminoalkene hydroamination catalysis with cationic Zr benzyl complexes is proposed to proceed through a σ-bond insertion mechanism. Proton loss from cationic Zr amido complexes to generate imido species is proposed with primary aminoalkenes, and the resultant neutral imido complexes can catalyze the cyclization of these substrates by the aforementioned imido-cycloaddition mechanism. The ability of the amidate ligand system to promote both mechanisms is unique in the field of alkene hydroamination catalysis.

A series of bidentate amidate ligands with variable groups R' and R" abbreviated by [R"(NO)R'] and adamantyl substituted tetradentate amidate ligands abbreviated by Ad[0₂N₂] were utilized as ancillaries for Ti, Zr, and Hf. Protonolysis routes into homoleptic amidate complexes, tris(amidate) mono(amido), bis(amidate) bis(amido), and bis(amidate) dibenzyl complexes are high yielding when performed with tetrakis(amido) and tetrabenzyl group 4 starting materials. Many of these complexes have been characterized in both the solid-state and in the solution phase, where in the latter case these complexes are fluxional and undergo exchange processes. Multiple geometric isomers are possible with the mixed N,0 chelate provided by the amidate ligands, and geometric isomerization of bis(amidate) bis(amido) complexes has been examined through X-ray crystallographic and density functional theory (DFT) calculations. Isomerization is dictated largely by the steric bulk present at the N of the amidate ligands, and is proposed to proceed through a K²-K¹-K² ligand isomerization mechanism, which is supported by crystallographic evidence of K¹-bound amidate ligands. The amidate ligand system binds to these metals in a largely electrostatic fashion, with poor orbital overlap, generating highly electrophilic metal centers. The bis(amidate) dibenzyl complexes of Zr and Hf are reactive towards insertion, abstraction, and protonolysis. Insertion of isocyanides into the Zr-C bonds of [DMP(NO) tBu]₂Zr(CH₂Ph₂ results in the formation of ƞ₂-iminoacyl complexes, which can either undergo thermally induced C=C coupling to generate an enediamido complex (aryl isocyanides), or rearrange to generate a bis(amidate) bis(vinylamido) complex (alkyl isocyanides). Benzyl abstraction to generate cationic Zr bis(amidate) benzyl complexes is also possible through reaction with [Ph₃C][B(C₆F₅)4] or B(C₆F₅)₃ Terminal imido complexes with novel pyramidal geometries are generated through protonolysis of bis(amidate) bis(amido) Ti and Zr complexes with primary aryl amines. DFT calculations demonstrate the existence of a Zr⁻₌N triple bond for these complexes. Dimeric imido complexes have been characterized in the solid state, but are not maintained in solution. Cycloaddition reactions of the terminal Zr imido complexes with C=0 bonds result in the formation of proposed oxo complexes and organic metathesis products. Catalytic aminoalkene cyclohydroamination has also been realized with these complexes, generating N-heterocyclic products. A series of kinetic and labeling studies support an imido-cycloaddition mechanism for catalytic cyclohydroamination of primary aminoalkenes with neutral bis(amidate) Ti and Zr precatalysts. The intermediate Ti imido complex, K²-[Dipp(NO)tBu-K¹_[DiPP(No) tBu]Ti=NCH₂CPh₂CH₂CH=CH₂(NHMe₂), has been isolated and characterized in the solid-state and in solution. Amine stabilized imido complexes of this type are invoked as the resting state for the catalytic reaction, and solution phase data support a chair-like geometry, where the alkene is coordinated to the metal center. A diastereoselectivity study supports this proposed solution structure. Eyring and Arrhenius parameters, as well as isolation of a 7-coordinate model imido complex, support a seven-coordinate transition state for the rate-determining metallacycle protonolysis reaction. In contrast, secondary aminoalkene hydroamination catalysis with cationic Zr benzyl complexes is proposed to proceed through a σ-bond insertion mechanism. Proton loss from cationic Zr amido complexes to generate imido species is proposed with primary aminoalkenes, and the resultant neutral imido complexes can catalyze the cyclization of these substrates by the aforementioned imido-cycloaddition mechanism. The ability of the amidate ligand system to promote both mechanisms is unique in the field of alkene hydroamination catalysis. / Science, Faculty of / Chemistry, Department of / Graduate

Amine bis(phenolate) ligands synthesis can be easily prepared by the reaction of a substituted 2-(bromomethyl)phenol, a substituted phenol, potassium carbonate, triethylamine and the appropriate amine to form the desired compounds in high yields and purities. A series of amine bis(phenolate) ligand precursors with group 4 metals and aluminum complexes have been prepared, characterized by single-crystal X-ray diffraction, and tested for ring opening polymerisation of £`-caprolactone. Group 4 metals complexes which are shown to be active catalysts for the ROP of £`-caprolactone with excellent conversions and polydispersities. All aluminum compounds as four-coordinate aluminum methyl complexes show excellent catalytic activity toward the ring opening polymerization of £`-caprolactone in the presence of benzyl alcohol. And amine bis(phenolate)s ligand ([tert-ButylONO]2-) bond cleavage with zirconium and hafnium complexes that have been prepared, characterized by single-crystal X-ray diffraction. Another zirconium complexes of dianionic amine bis(phenolate) ligands have been synthesized, their X-ray structures solved, and their activity as 1-hexene polymerization catalysts study. Upon treatment with B(C6F5)3, a series of pentacoordinate [ONO]Zr(CH2Ph)2 complex, having no extra donor group, shows only poor activity as a polymerization catalyst. Final reaction of diamine-bis(phenol) ligands containing a mixture of [i-PropylONO]Ti(OiPr)2 in dry THF under RT without exclusion of air and moisture gives {[i-PropylONO]TiO}3 (characterised by X-ray crystallography) is hydrolysed with H2O.

No description available.