Polymerization of norbornene by olefin metathesis catalysts: insertion and ring opening in the same chain

Johnston, Jay A.; Tokles, Maritherese; Hatvany, Gerard S.; Rinaldi, Peter L.; Farona, Michael F.

doi:10.1021/ma00020a008

Cited by 22 publications

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Section: Dedicated To Professor Walter Kaminsky On the Occasion Of Himentioning

confidence: 99%

“…[10][11][12][13][14] In fact, because of the high crystallinity of these polymers, it was argued that two different polymers, that is, one VIP-and one ROMP-derived, had formed concomitantly. The first unequivocal evidence for the presence of both ROMP-and VIP-derived structures within one single polymer chain was reported by Farina et al using Mo-and Re-based initiators; [15,16] they unambiguously assigned characteristic signals for the quaternary carbon and for the methylene group in VIP/ROMP-derived poly(NBE) (Scheme 1 c).In fact, the structure of this particular polymer can be explained only by a reversible a-elimination/a-addition process, which permits VIP and ROMP to take place within the same polymer chain. Owing to the relationship between VIP and ROMP, even one single switch between VIP and ROMP, resulting in the synthesis of AB diblock copolymers, has attracted attention.…”

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A Catalyst for the Simultaneous Ring‐Opening Metathesis Polymerization/Vinyl Insertion Polymerization

et al. 2011

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Dedicated to Professor Walter Kaminsky on the occasion of his 70th birthdayBoth the vinyl insertion polymerization (VIP) of olefins [1][2][3][4][5][6][7] and the ring-opening metathesis polymerization (ROMP) [8,9] of cyclic olefins are well-established polymerization techniques based on the insertion of a monomer between a transition metal (ion) and a growing polymer chain. In fact, they are related to each other, since a cationic, VIP-active catalyst may be converted into a ROMP-active catalyst by a simple a-elimination process. In contrast, the reverse process, that is, the a addition of a proton to a metal alkylidene to form a cationic VIPactive species, is much more difficult to accomplish in a controlled way.The occurrence of both VIP-(Scheme 1 a) and ROMP-derived (Scheme 1 b) structures in poly(NBE) (NBE = norborn-2-ene) was observed already in the early days of polyolefin chemistry and paved the way for identifying and understanding metathesis-based processes. [10,11] Nevertheless, at that time there was no clear evidence for the presence of both structures, that is, both ROMP-and VIP-derived repeat units, within one single polymer chain. [10][11][12][13][14] In fact, because of the high crystallinity of these polymers, it was argued that two different polymers, that is, one VIP-and one ROMP-derived, had formed concomitantly. The first unequivocal evidence for the presence of both ROMP-and VIP-derived structures within one single polymer chain was reported by Farina et al. using Mo-and Re-based initiators; [15,16] they unambiguously assigned characteristic signals for the quaternary carbon and for the methylene group in VIP/ROMP-derived poly(NBE) (Scheme 1 c).In fact, the structure of this particular polymer can be explained only by a reversible a-elimination/a-addition process, which permits VIP and ROMP to take place within the same polymer chain. Owing to the relationship between VIP and ROMP, even one single switch between VIP and ROMP, resulting in the synthesis of AB diblock copolymers, has attracted attention. Thus, Grubbs et al. reported on a titanacyclobutane compound active in the ROMP of NBE; upon addition of an alcohol and activation with Et 2 AlCl, a cationic species was created that is active in the VIP of ethylene (E), resulting in the synthesis of poly(NBE) ROMP -bpoly(E).[17] Kaminsky et al. reported on a controlled switch from VIP to ROMP in the preparation of poly(NBE) VIP -bpoly(NBE) ROMP , poly(NBE) VIP -b-poly(CPE) ROMP , and poly-(NBE) VIP -b-poly(COE) ROMP (CPE = cyclopentene, COE = cis-cyclooctene).

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Section: Dedicated To Professor Walter Kaminsky On the Occasion Of Himentioning

confidence: 99%

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confidence: 99%

A Catalyst for the Simultaneous Ring‐Opening Metathesis Polymerization/Vinyl Insertion Polymerization

et al. 2011

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“…[10][11][12][13][14] Vielmehr wurde wegen der hohen Kristallinität der Polymere die Bildung zweier verschiedener Polymere, d. h. eines VIP-und eines ROMP-abgeleiteten Polymers, diskutiert. So gelang es erst Farina et al zu einem späteren Zeitpunkt, ROMP-und VIP-abgeleitete Strukturen innerhalb einer einzigen Poly(NBE)-Kette, hergestellt mit Mound Re-basierten Initiatoren, eindeutig nachzuweisen [15,16] und die charakteristischen Signale der quartären Kohlenstoffatome und der Methylengruppen in VIP-/ROMP-abgeleitetem Poly(NBE) (Schema 1 c) zweifelsfrei zuzuordnen.…”

Section: Professor Walter Kaminsky Zum 70 Geburtstag Gewidmetunclassified

Ein Katalysator für die Tandem‐Ringöffnungsmetathesepolymerisation/Vinylinsertionspolymerisation

et al. 2011

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“…Hard evidence for the presence of both ROMP-and VIP-derived structures (Scheme 1c) within one single poly-A C H T U N G T R E N N U N G (NBE) polymer chain was reported by the Farina group. [15,16] The structure of this particular polymer can only be explained in terms of a reversible a-H elimination/a-H addition process, with both VIP and ROMP occurring within the same polymer chain. Controlled, single switches from ROMP to VIP and vice versa have been reported by the groups of Grubbs and Kaminsky, which enabled them to synthesize AB diblock copolymers.…”

Section: Introductionmentioning

confidence: 99%

Group 4 Dimethylsilylenebisamido Complexes Bearing the 6‐[2‐(Diethylboryl)phenyl]pyrid‐2‐yl Motif: Synthesis and Use in Tandem Ring‐Opening Metathesis/Vinyl‐Insertion Copolymerization of Cyclic Olefins with Ethylene

Zou

Wang

Wurst

et al. 2011

Chemistry A European J

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Two novel Zr(IV)- and Hf(IV)-based bisamido complexes bearing the 6-[2-(diethylboryl)phenyl]pyrid-2-yl motif, that is, [ZrCl(2){Me(2)Si(DbppN)(2)}(thf)] (9) and [HfCl(2){Me(2)Si(DbppN)(2)}(thf)(2)] (10) (DbppN=6-[2-(diethylboryl)phenyl]pyridine-2-amido) have been prepared. Their reactivities have been compared with that of a model precatalyst that does not bear the aminoborane motif. Upon activation with methylalumoxane, precatalysts 9 and 10 are active in the homopolymerization of ethylene (E) yielding high-density polyethylene (HDPE). In the copolymerization of E with cyclopentene (CPE), for example by the action of 9, the presence of CPE resulted in a dramatic increase in the polymerization activity of E, while CPE incorporation remained close to or at zero. In the vinyl-insertion copolymerization of norborn-2-ene (NBE) with E by the action of 9, statistical cyclic olefin copolymers of these two monomers were obtained. At higher NBE concentrations, however, 9 gave rise to reversible ring-opening metathesis (ROMP)/vinyl-insertion polymerization (VIP) of NBE with E, resulting in the formation of multi-block copolymers of the general formula poly(NBE)(ROMP)-co-poly(NBE)(VIP)-co-poly(E). This particular feature of precatalyst 9, that is, the ability to induce a reversible α-H elimination/α-H addition reaction, is attributed to the unique role of the 6-[2-(diethylboryl)phenyl]pyrid-2-yl ligand. Accordingly, a model precatalyst lacking this ligand does not have the ability to induce α-H elimination/α-H addition reactions. The different (11)B NMR shifts of various diethylborylphenylpyrid-2-ylamines and -amides permit a ranking of the strengths of the B-N bonds in these compounds. This strength of the B-N bond is correlated with the propensity of 9/MAO to produce poly(NBE)(ROMP)-co-poly(NBE)(VIP)-co-poly(E) at different temperatures.

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Polymerization of norbornene by olefin metathesis catalysts: insertion and ring opening in the same chain

Cited by 22 publications

References 1 publication

A Catalyst for the Simultaneous Ring‐Opening Metathesis Polymerization/Vinyl Insertion Polymerization

A Catalyst for the Simultaneous Ring‐Opening Metathesis Polymerization/Vinyl Insertion Polymerization

Ein Katalysator für die Tandem‐Ringöffnungsmetathesepolymerisation/Vinylinsertionspolymerisation

Group 4 Dimethylsilylenebisamido Complexes Bearing the 6‐[2‐(Diethylboryl)phenyl]pyrid‐2‐yl Motif: Synthesis and Use in Tandem Ring‐Opening Metathesis/Vinyl‐Insertion Copolymerization of Cyclic Olefins with Ethylene

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