Roller Design and Optimization Based on RSM with Categoric Factors in Power Spinning of Ni-Based Superalloy

Power spinning is a single point high pressure forming process which is usually studied with ideal regular billet. However, in some cases, the billet adopted in this process is from conventional spinning process with non-uniform wall thickness and springback. Therefore, the forming accuracy is low because this unpredictable spun billet. In this paper, cone, step and arc rollers are compared and the length change of deformation zone is calculated to further understand the forming mechanism of different roller shapes. Multi-step process simulation considering conventional spinning and power spinning is established. The influence of roller parameters such as roller nose radius, straightening zone in step roller and bite angle on the maximum roller force are discussed. In addition, the continuous factors such as installation angle and discrete factor roller shape are studied based on the response surface method (RSM) with categoric factors. The results show that roller shape have a big influence on the workpiece forming quality in power spinning process. Step roller is more suitable for use in this work. The roller nose radius and installation angle have great impacts on the maximum roller force.

Synthesis, Properties, and Coordination Chemistry of t-Bu-Xantphos Ligands

<p>This thesis provides an account of research into a group of diphosphine ligands with a rigid xanthene backbone and tert -butyl substituents on the phosphorus atoms. The three ligands have different groups in the bridgehead position of the backbone (CMe₂, SiMe₂, or S) which change the natural (calculated) bite-angle of the ligand. The coordination chemistry of these t -Bu-xantphos ligands with late-transition metals has been investigated with a focus on metal complexes that may form in catalytic reactions. The three t -Bu-xantphos ligands were synthesised by lithiation of the backbone using sec -butyllithium/TMEDA and treatment with PtBu₂Cl. The natural biteangles of the Ph-xantphos (111.89–114.18°) and t -Bu-xantphos (126.80–127.56°) ligands were calculated using DFT. The bite-angle of the t -Bu-xantphos ligands is larger due to the increased steric bulk of the tert -butyl substituents. The electronic properties of the t -Bu-xantphos ligandswere also investigated by synthesis of their phosphine selenides. The values of ¹J PSe (689.1–698.5Hz) indicate that the t -Bu-xantphos ligands have a higher basicity than Ph-xantphos between PPh₂Me and PMe₃. The silver complexes, [Ag(t -Bu-xantphos)Cl] and [Ag(t -Bu-xantphos)]BF₄ were synthesised with the t -Bu-xantphos ligands. In contrast to systems with phenyl phosphines, all species were monomeric. [Rh(t -Bu-xantphos)Cl] complexes were synthesised, which reacted with H₂, forming [Rh(t -Bu-xantphos-ĸP,O,P ’)Cl(H)₂] complexes, and with CO, forming [Rh(t -Bu-xantphos)(CO)₂Cl] complexes. The [Rh(t -Bu-xantphos)Cl] species are air-sensitive readily forming [Rh(t -Bu-xantphos)Cl(ƞ²-O₂)] complexes. The crystal structure of [Rh(t -Bu-xantphos)Cl(ƞ²-O₂)], contained 15% of the dioxygen sites replaced with an oxo ligand. This is the first crystallographic evidence of a rhodium(III) oxo complex, and only the third rhodium oxo species reported. The coordination chemistry of the ligands with platinum(0) and palladium(0) showed some differences. [Pt(t -Bu-xantphos)(C₂H₄)] complexes were synthesised for all three ligands. However, reaction with [Pt(nb)₃] produced a mixture of [Pt(t -Bu-xantphos)] and [Pt(t -Bu-xantphos)(nb)] for t -Bu-sixantphos and t -Buthixantphos. Although few examples of isolable [Pt(PP)] complexes with diphosphines have been reported [Pt(t -Bu-thixantphos)] was isolated by removal of the norbornene. t -Bu-Xantphos formed small amounts of [Pt(t -Bu-xantphos)] initially, which progressed to [Pt(t -Bu-xantphos)H]X. The analogous reactions with [Pd(nb)₃] gave [Pd(t -Bu-xantphos)] and [Pd(t -Bu-xantphos)(nb)] complexes in all cases. [Pt(t -Bu-thixantphos)(C₂H₄)] and [M(t -Bu-thixantphos)] (M = Pd, Pt) react with oxygen forming [Pt(t -Bu-thixantphos)(ƞ²-O₂)], which reacts with CO to give [Pt(t -Bu-thixantphos-H-ĸ-C,P,P ’)OH] through a series of intermediates. [M(t -Bu-xantphos)Cl₂] (M = Pd, Pt) complexes were synthesised, showing exclusive trans coordination of the diphosphine ligands. The X-ray crystal structure of [Pt(t -Bu-thixantphos)Cl₂] has a bite-angle of 151.722(15)°. This is the first [PtCl₂(PP)] complex with a bite-angle between 114 and 171°. In polar solvents a chloride ligand dissociates from the [Pt(t -Bu-xantphos)Cl₂] complexes producing [Pt(t -Bu-xantphos-ĸP,O,P ’)Cl]⁺. The analogous [Pd(t -Bu-xantphos-ĸP,O,P ’)Cl]⁺ complexes were formed by reaction of the dichlorides complexes with NH₄PF₆. The [Pt(t -Bu-xantphos-ĸP,O,P ’)Me]⁺ pincer complexes were the only product from reaction with [Pt(C₆H₁₀)ClMe], with the stronger trans influence of the methyl ligand promoting loss of the chloride. The formation of the pincer complexes was further explored using DFT. The values of J PtC for the methyl carbons in the [Pt(t -Bu-xantphos-ĸP,O,P ’)Me]⁺ complexes, and J RhH for the hydride trans to the oxygen atom in the [Rh(t -Buxantphos-ĸP,O,P ’)Cl(H)₂] complexes were largest for t -Bu-sixantphos, then t -Buthixantphos, then t -Bu-xantphos. The trans influence of the t -Bu-xantphos oxygen donor follows the trend t -Bu-sixantphos < t -Bu-thixantphos < t -Bu-xantphos.</p>

Synthesis, Properties, and Coordination Chemistry of t-Bu-Xantphos Ligands

<p>This thesis provides an account of research into a group of diphosphine ligands with a rigid xanthene backbone and tert -butyl substituents on the phosphorus atoms. The three ligands have different groups in the bridgehead position of the backbone (CMe₂, SiMe₂, or S) which change the natural (calculated) bite-angle of the ligand. The coordination chemistry of these t -Bu-xantphos ligands with late-transition metals has been investigated with a focus on metal complexes that may form in catalytic reactions. The three t -Bu-xantphos ligands were synthesised by lithiation of the backbone using sec -butyllithium/TMEDA and treatment with PtBu₂Cl. The natural biteangles of the Ph-xantphos (111.89–114.18°) and t -Bu-xantphos (126.80–127.56°) ligands were calculated using DFT. The bite-angle of the t -Bu-xantphos ligands is larger due to the increased steric bulk of the tert -butyl substituents. The electronic properties of the t -Bu-xantphos ligandswere also investigated by synthesis of their phosphine selenides. The values of ¹J PSe (689.1–698.5Hz) indicate that the t -Bu-xantphos ligands have a higher basicity than Ph-xantphos between PPh₂Me and PMe₃. The silver complexes, [Ag(t -Bu-xantphos)Cl] and [Ag(t -Bu-xantphos)]BF₄ were synthesised with the t -Bu-xantphos ligands. In contrast to systems with phenyl phosphines, all species were monomeric. [Rh(t -Bu-xantphos)Cl] complexes were synthesised, which reacted with H₂, forming [Rh(t -Bu-xantphos-ĸP,O,P ’)Cl(H)₂] complexes, and with CO, forming [Rh(t -Bu-xantphos)(CO)₂Cl] complexes. The [Rh(t -Bu-xantphos)Cl] species are air-sensitive readily forming [Rh(t -Bu-xantphos)Cl(ƞ²-O₂)] complexes. The crystal structure of [Rh(t -Bu-xantphos)Cl(ƞ²-O₂)], contained 15% of the dioxygen sites replaced with an oxo ligand. This is the first crystallographic evidence of a rhodium(III) oxo complex, and only the third rhodium oxo species reported. The coordination chemistry of the ligands with platinum(0) and palladium(0) showed some differences. [Pt(t -Bu-xantphos)(C₂H₄)] complexes were synthesised for all three ligands. However, reaction with [Pt(nb)₃] produced a mixture of [Pt(t -Bu-xantphos)] and [Pt(t -Bu-xantphos)(nb)] for t -Bu-sixantphos and t -Buthixantphos. Although few examples of isolable [Pt(PP)] complexes with diphosphines have been reported [Pt(t -Bu-thixantphos)] was isolated by removal of the norbornene. t -Bu-Xantphos formed small amounts of [Pt(t -Bu-xantphos)] initially, which progressed to [Pt(t -Bu-xantphos)H]X. The analogous reactions with [Pd(nb)₃] gave [Pd(t -Bu-xantphos)] and [Pd(t -Bu-xantphos)(nb)] complexes in all cases. [Pt(t -Bu-thixantphos)(C₂H₄)] and [M(t -Bu-thixantphos)] (M = Pd, Pt) react with oxygen forming [Pt(t -Bu-thixantphos)(ƞ²-O₂)], which reacts with CO to give [Pt(t -Bu-thixantphos-H-ĸ-C,P,P ’)OH] through a series of intermediates. [M(t -Bu-xantphos)Cl₂] (M = Pd, Pt) complexes were synthesised, showing exclusive trans coordination of the diphosphine ligands. The X-ray crystal structure of [Pt(t -Bu-thixantphos)Cl₂] has a bite-angle of 151.722(15)°. This is the first [PtCl₂(PP)] complex with a bite-angle between 114 and 171°. In polar solvents a chloride ligand dissociates from the [Pt(t -Bu-xantphos)Cl₂] complexes producing [Pt(t -Bu-xantphos-ĸP,O,P ’)Cl]⁺. The analogous [Pd(t -Bu-xantphos-ĸP,O,P ’)Cl]⁺ complexes were formed by reaction of the dichlorides complexes with NH₄PF₆. The [Pt(t -Bu-xantphos-ĸP,O,P ’)Me]⁺ pincer complexes were the only product from reaction with [Pt(C₆H₁₀)ClMe], with the stronger trans influence of the methyl ligand promoting loss of the chloride. The formation of the pincer complexes was further explored using DFT. The values of J PtC for the methyl carbons in the [Pt(t -Bu-xantphos-ĸP,O,P ’)Me]⁺ complexes, and J RhH for the hydride trans to the oxygen atom in the [Rh(t -Buxantphos-ĸP,O,P ’)Cl(H)₂] complexes were largest for t -Bu-sixantphos, then t -Buthixantphos, then t -Bu-xantphos. The trans influence of the t -Bu-xantphos oxygen donor follows the trend t -Bu-sixantphos < t -Bu-thixantphos < t -Bu-xantphos.</p>

Hybrid P,E Ligands: Synthesis, Coordination Chemistry and Catalysis

<p>This thesis provides an account of research into a family of novel hybrid P,E ligands containing an o-xylene backbone. A methodology for the synthesis of these ligands has been developed, and their coordination behaviour with platinum(II) and platinum(0) precursors has been explored, with particular focus on a phosphinethioether (P,S) ligand of this type. The coordination modes of this P,S ligand with palladium precursors have also been investigated, and the utility of the ligand in a palladium and copper co-catalysed Sonogashira carbon-carbon bond-forming reaction has been evaluated. A range of hybrid P,E ligands of the type o-C₆H₄(CH₂PBut₂)(CH₂E) (E = PR₂, SR, S(O)But, NR₂, SiPh₂H) have been synthesised in two or three steps from the novel substrate, o-C₆H₄(CH₂PBut₂(BH₃)}(CH₂Cl). The initial step involved treatment of the substrate with the appropriate nucleophilic reagent, or preparation of a Grignard reagent from o-C₆H₄{CH₂PBut₂(BH₃)}(CH₂Cl) and reaction with the appropriate electrophile. In most cases, this versatile strategy produced air-stable crystalline ligand precursors. Phosphine deprotection was achieved via one of three methods, dependent upon the properties of the second functional group. The reactivity of three of these ligands — o-C₆H₄{CH₂PBut₂)(CH₂SBut) (14a), o-C₆H₄{CH₂PBut₂){CH₂S(O)But} (16) and o-C₆H₄(CH₂PBut₂)(CH₂NMe₂) (18a) — with Pt(II) and Pt(0) precursor complexes has been investigated. Chelated [PtCl₂(P,E)] complexes were synthesised with P,S ligand 14a and P,N ligand 18a, but attempts to produce the equivalent species with P,S=O ligand 16 were unsuccessful. The X-ray crystal structure of [PtCl₂(P,S)] complex 21 displayed an unexpectedly small ligand bite angle of 86.1°. A series of platinum(II) hydride complexes of the types [PtHL(P,S)₂] and [PtHL(P,S)₂]CH(SO₂CF₃)₂ (L = Cl¯, H¯, NCMe, −CH₂SBut , CO, pta) have been synthesised, where ligand 14a binds in a monodentate fashion through the phosphorus donor atom. This work has demonstrated the hemilability of ligand 14a, via the facile and reversible conversion between [PtH(κ¹P-14a)(κ²P,S-14a)]CH(SO₂CF₃)₂ (26) and [PtH(NCMe)(κ¹P-14a)₂]CH(SO₂CF₃)₂ (28). The X-ray crystal structure of [PtH₂(P,S)₂] complex 25 was used to calculate a cone angle of 180° for the phosphine moiety in ligand 14a. Reaction of P,S ligand 14a and P,S=O ligand 16 with [Pt(alkene)₃] complexes (alkene = ethene, norbornene) gave the chelated [Pt(alkene)(P,E)] complexes 32–35; however, under similar conditions a [Pt(norbornene)(P,N)] complex did not form. A large ligand bite angle of 106.6° was observed in the X-ray crystal structure of [Pt(norbornene)(P,S)] complex 34. Reaction of two equivalents of each of the P,E ligands with [Pt(norbornene)₃] gave the corresponding 14-electron linear complexes [Pt(P,E)₂] (36–38) with the ligands coordinated through the phosphorus donor atoms only. The reactivity of [Pt(norbornene)(P,S)] complex 34 and [Pt(P,S)₂] complex 36 has been investigated, resulting in the complexes [PtH{CH(SO₂CF₃)₂}(P,S)] (39), [Pt(norbornyl)(P,S)] (40), [Pt(ethyne)(P,S)] (41) and [Pt(O₂)(P,S)₂] (42). The reactivity of P,S ligand 14a was investigated with Pd(II) and Pd(0) precursors, resulting in the identification of five coordination modes of this ligand. Monodentate binding was observed in [Pd(P,S)₂] complex 44, and chelation in the [Pd(alkene)(P,S)] complexes 47 (alkene = norbornene) and 48 (alkene = dba). Reaction of ligand 14a with [PdCl₂(NCBut)₂] at raised temperature resulted in S−C bond cleavage and the formation of palladium dimer 43 with bidentate coordination of the ligand through phosphine and bridging thiolate moieties. Reaction of ligand 14a with [Pd(OAc)₂] resulted in C−H activation of the aryl backbone and formation of [Pd(μ-OAc)(P,C)]₂ dimer 46. In the presence of excess [Pd(OAc)₂], palladium hexamer 45 was formed, with a combination of P,C palladacycle and monodentate thioether binding resulting in bridging P,C,S coordination of ligand 14a. The Sonogashira cross-coupling of 4-bromoanisole and phenylethyne was performed with 3 mol% of a pre-catalyst mixture containing P,S ligand 14a, [Pd(OAc)₂] and CuI, resulting in quantitative conversion to 4-(phenylethynyl)anisole in four hours. Two enyne by-products were also identified from the reaction. Variations to the pre-catalyst mixture and catalyst loading indicated there was a significant ligand dependence on the yield and selectivity of the reactions. Mercury drop tests and dynamic light scattering experiments confirmed the presence of palladium nanoparticles in the reaction solution; however, the active catalytic species in these reactions has not been identified.</p>

Hybrid P,E Ligands: Synthesis, Coordination Chemistry and Catalysis

<p>This thesis provides an account of research into a family of novel hybrid P,E ligands containing an o-xylene backbone. A methodology for the synthesis of these ligands has been developed, and their coordination behaviour with platinum(II) and platinum(0) precursors has been explored, with particular focus on a phosphinethioether (P,S) ligand of this type. The coordination modes of this P,S ligand with palladium precursors have also been investigated, and the utility of the ligand in a palladium and copper co-catalysed Sonogashira carbon-carbon bond-forming reaction has been evaluated. A range of hybrid P,E ligands of the type o-C₆H₄(CH₂PBut₂)(CH₂E) (E = PR₂, SR, S(O)But, NR₂, SiPh₂H) have been synthesised in two or three steps from the novel substrate, o-C₆H₄(CH₂PBut₂(BH₃)}(CH₂Cl). The initial step involved treatment of the substrate with the appropriate nucleophilic reagent, or preparation of a Grignard reagent from o-C₆H₄{CH₂PBut₂(BH₃)}(CH₂Cl) and reaction with the appropriate electrophile. In most cases, this versatile strategy produced air-stable crystalline ligand precursors. Phosphine deprotection was achieved via one of three methods, dependent upon the properties of the second functional group. The reactivity of three of these ligands — o-C₆H₄{CH₂PBut₂)(CH₂SBut) (14a), o-C₆H₄{CH₂PBut₂){CH₂S(O)But} (16) and o-C₆H₄(CH₂PBut₂)(CH₂NMe₂) (18a) — with Pt(II) and Pt(0) precursor complexes has been investigated. Chelated [PtCl₂(P,E)] complexes were synthesised with P,S ligand 14a and P,N ligand 18a, but attempts to produce the equivalent species with P,S=O ligand 16 were unsuccessful. The X-ray crystal structure of [PtCl₂(P,S)] complex 21 displayed an unexpectedly small ligand bite angle of 86.1°. A series of platinum(II) hydride complexes of the types [PtHL(P,S)₂] and [PtHL(P,S)₂]CH(SO₂CF₃)₂ (L = Cl¯, H¯, NCMe, −CH₂SBut , CO, pta) have been synthesised, where ligand 14a binds in a monodentate fashion through the phosphorus donor atom. This work has demonstrated the hemilability of ligand 14a, via the facile and reversible conversion between [PtH(κ¹P-14a)(κ²P,S-14a)]CH(SO₂CF₃)₂ (26) and [PtH(NCMe)(κ¹P-14a)₂]CH(SO₂CF₃)₂ (28). The X-ray crystal structure of [PtH₂(P,S)₂] complex 25 was used to calculate a cone angle of 180° for the phosphine moiety in ligand 14a. Reaction of P,S ligand 14a and P,S=O ligand 16 with [Pt(alkene)₃] complexes (alkene = ethene, norbornene) gave the chelated [Pt(alkene)(P,E)] complexes 32–35; however, under similar conditions a [Pt(norbornene)(P,N)] complex did not form. A large ligand bite angle of 106.6° was observed in the X-ray crystal structure of [Pt(norbornene)(P,S)] complex 34. Reaction of two equivalents of each of the P,E ligands with [Pt(norbornene)₃] gave the corresponding 14-electron linear complexes [Pt(P,E)₂] (36–38) with the ligands coordinated through the phosphorus donor atoms only. The reactivity of [Pt(norbornene)(P,S)] complex 34 and [Pt(P,S)₂] complex 36 has been investigated, resulting in the complexes [PtH{CH(SO₂CF₃)₂}(P,S)] (39), [Pt(norbornyl)(P,S)] (40), [Pt(ethyne)(P,S)] (41) and [Pt(O₂)(P,S)₂] (42). The reactivity of P,S ligand 14a was investigated with Pd(II) and Pd(0) precursors, resulting in the identification of five coordination modes of this ligand. Monodentate binding was observed in [Pd(P,S)₂] complex 44, and chelation in the [Pd(alkene)(P,S)] complexes 47 (alkene = norbornene) and 48 (alkene = dba). Reaction of ligand 14a with [PdCl₂(NCBut)₂] at raised temperature resulted in S−C bond cleavage and the formation of palladium dimer 43 with bidentate coordination of the ligand through phosphine and bridging thiolate moieties. Reaction of ligand 14a with [Pd(OAc)₂] resulted in C−H activation of the aryl backbone and formation of [Pd(μ-OAc)(P,C)]₂ dimer 46. In the presence of excess [Pd(OAc)₂], palladium hexamer 45 was formed, with a combination of P,C palladacycle and monodentate thioether binding resulting in bridging P,C,S coordination of ligand 14a. The Sonogashira cross-coupling of 4-bromoanisole and phenylethyne was performed with 3 mol% of a pre-catalyst mixture containing P,S ligand 14a, [Pd(OAc)₂] and CuI, resulting in quantitative conversion to 4-(phenylethynyl)anisole in four hours. Two enyne by-products were also identified from the reaction. Variations to the pre-catalyst mixture and catalyst loading indicated there was a significant ligand dependence on the yield and selectivity of the reactions. Mercury drop tests and dynamic light scattering experiments confirmed the presence of palladium nanoparticles in the reaction solution; however, the active catalytic species in these reactions has not been identified.</p>

Asymmetric Hydrogenation of γ-Branched Allylamines for the Efficient Synthesis of γ-Chirogenic Amines

The efficient construction of γ-chirogenic amines has been realized via asymmetric hydrogenation of γ-branched N-phthaloyl allylamines by using a bisphosphine-Rh catalyst bearing a large bite angle. The desired products possessing different types of γ-substituents were obtained in quantitative yields and with excellent enantioselectivities (up to >99.9% ee). This protocol provided a practical method for the preparation of γ-chirogenic amine derivatives such as the famous antidepressant drug Fluoxetine (up to 50000 S/C). The mechanism calculation shows a weak interaction-promoted activation mode which is completely different from the traditional coordination-promoted activation mode in the Rh-catalyzed hydrogenation.

Ligand isomerism in Pt(II) complexes – structural aspects

This review has focused on ligand isomers in Pt(II) complexes. There are a variety of inner coordination spheres about the platinum(II) atom (PtN4, PtN2Cl2, PtP2Cl2, PtPNC2, PtPNCl2, PtP2CBr, PtP2CS), build up by mono- and bidentate ligands. The bidentate ligands create a variety of metallocyclic rings. The L–Pt–L bite angle (mean values) open in the sequence: 73.1° (PNP) < 78.7° (NC2C) < 80.4° (NC2N) < 86.4° (PC2P) < 86.7° (PNNP) < 93.0° (CC3S). There are three types of isomers: ligand, mixed – (ligand + distortion), and mixed – (ligand + cis-trans), isomers, which are rarity.