New Phenoxyketimine Titanium Complexes:  Combining Isotacticity and Living Behavior in Propylene Polymerization

Mason, Andrew F.; Coates, Geoffrey W.

doi:10.1021/ja044268s

Cited by 156 publications

(84 citation statements)

References 20 publications

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“…The addition of a chaotropic salt, such as guanidine hydrochloride or guanidine thiocyanate, to the system is an endothermic process with a positive entropy change. With as many as 10 molecules of water bound per molecule of guanidine hydrochloride, 8 the hydration of the chaotrope effectively dehydrates both the DNA molecules and the silica surface. Typically, B-DNA will bind ∼20 water molecules per nucleotide; however, addition of the chaotropic salt decreases the water activity and induces a conformational change of helical B-DNA to either the C-or A-DNA.…”

Section: Silica-based Purification Of Nasmentioning

confidence: 99%

Purification of Nucleic Acids in Microfluidic Devices

et al. 2008

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Section: Silica-based Purification Of Nasmentioning

confidence: 99%

Purification of Nucleic Acids in Microfluidic Devices

et al. 2008

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“…Recently, in association with MAO, Ti-Fi catalyst 25 having a phenyl group on the imine-C has been described by Mason and Coates to produce moderately isotactic and nearly monodisperse PP (0 C polymerization; mmmm 53%, T m 69.5 C, M n 27900, M w =M n 1.11), probably due to the suppression of a site-inversion process by the phenyl group on the imine-C. 32 The corresponding Ti-FI catalysts possessing a sterically bulkier ortho-substituent (which is expected to form higher tacticity PPs) display practically no reactivity toward propylene. Thus, highly isospecific and living propylene polymerization with FI catalysts has not yet been achieved, which seems difficult when one considers the catalyst structure and performance relationships elucidated by Furuyama,Mitani and Fujita.…”

Section: Living Propylene Polymerizationmentioning

confidence: 99%

Living Olefin Polymerization and Block Copolymer Formation with FI Catalysts

Sakuma

Weiser

Fujita

2007

Polym J

104

126

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ABSTRACT:This contribution reports on the recent advances in living olefin polymerization catalysis and block copolymer formation made by fluorinated bis(phenoxy-imine)Ti complexes (fluorinated Ti-FI catalysts), which were discovered by Mitsui Chemicals. Fluorinated Ti-FI catalysts are capable of mediating thermally robust living ethylene and highly stereoselective living propylene polymerization. This highly controlled living nature has made it possible to synthesize a wide variety of monodisperse polymers, functionalized polymers and block copolymers from ethylene, propylene, higher -olefins, cyclic olefins and styrene. The living FI polymers possess unique and often previously inaccessible microstructures, and some of the FI polymers were revealed to display unique morphologies and useful material properties. Therefore, the discovery and development of the fluorinated Ti-FI catalysts has not only made a significant impact on living olefin polymerization catalysis but has also given industry opportunities to make unique polyolefin-based materials for the benefit of the world at large. Producing polymers with perfectly controlled molecular weight, molecular weight distribution, composition and architecture has been an ultimate goal in the field of polymer synthesis. Living olefin polymerization permits consecutive enchainment of monomer units without termination, and thus is an excellent way of synthesizing polyolefin-based block copolymers and chain-end functionalized polyolefins as well as precisely controlling molecular weight and composition.1 These living polymers have the potential to be excellent compatibilizers, modifiers, additives and elastomers.Since Doi's pioneering work on living propylene polymerization using a vanadium-based catalyst, 2 much effort has been devoted to the discovery and development of catalysts capable of mediating the living polymerization of olefinic monomers. Recent progress in the rational design of transition metal complexes for olefin polymerization 3 has spurred the development of high performance catalysts based on both early and late transition metal complexes for living olefin polymerization.4 Recent reviews cover much of this work. 5Researchers at Mitsui Chemicals developed phenoxy-imine ligated early transition metal complexes for the controlled (co)polymerization of olefinic monomers (now known as FI catalysts), 6,7 capable of producing a wide variety of unique polymers including selective vinyl-and Al-terminated polyethylenes (PEs), well-defined multimodal PEs, highly isotactic and syndiotactic polypropylenes (iPPs and sPPs), and regio-and stereoirregular high molecular weight poly(higher -olefin)s. 8 After extensive research on FI catalysts, Mitsui researchers in 1999 discovered fluorinated Ti-FI catalysts that can promote unprecedented living ethylene and propylene polymerizations, resulting in the formation of functionalized polymers and block copolymers from ethylene, propylene and higher -olefins. 7,9-11The above results have stimulated even further research on ...

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“…[38,39] Previous X-ray crystallographic studies have established that of the five possible isomeric structures of (bidentate) 2 -MX 2 complexes (bidentate = aryloxy-imine ligand, X = unidentate ligand) ( Figure 1) the preferred structure is a distorted octahedron with trans-O,cis-N,cis-X ligand arrangement [ Figure 1(i)], [14,[23][24][25][26][27][28][29][30]40,41] a feature that has also Scheme 1. Synthesis of ligands 1a-l and Ti complexes 2a-k.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Isolation and Structural Investigation of Schiff‐Base Alkoxytitanium Complexes: Steric Limitations of Ligand Coordination

et al. 2006

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This paper reports the reaction of Ti(OiPr) 4 with a series of Schiff-base ligands. The Schiff-base proligands 1a-l are synthesised by the condensation of salicylaldehyde with a range of primary alkylamine and aniline derivatives. The treatment of 1a-f with Ti(OiPr) 4 yields the octahedral bis(aryloxyimine)Ti(OiPr) 2 complexes 2a-f. X-ray crystal structure analysis of 2c, 2d and 2e reveals complexes with a trans-aldiminato oxygen atom and cis-N,cis-alkoxide ligand arrangement about the central metal atom. The reactions of Ti(OiPr) 4 with the ligands 1g and 1h result in a sterically induced ligand rearrangement to form the octahedral complexes 2g and 2h, also characterised by X-ray diffraction experiments, in which the nitrogen atoms of the O,N-chelate are now trans-orientated at the titanium centre.1 H NMR analysis reveals significant deshielding of the isopropoxide methine proton, in-

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New Phenoxyketimine Titanium Complexes: Combining Isotacticity and Living Behavior in Propylene Polymerization

Cited by 156 publications

References 20 publications

Purification of Nucleic Acids in Microfluidic Devices

Purification of Nucleic Acids in Microfluidic Devices

Living Olefin Polymerization and Block Copolymer Formation with FI Catalysts

Synthesis, Isolation and Structural Investigation of Schiff‐Base Alkoxytitanium Complexes: Steric Limitations of Ligand Coordination

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