Selective Ring Opening Allene Metathesis: Polymerization or Ruthenium Vinylidene Formation

10.26434/chemrxiv.14109950 ◽

2021 ◽

Author(s):

William Neary ◽

Yunyan Sun ◽

Jeffrey S. Moore

Keyword(s):

Ring Opening ◽

First Generation ◽

Elevated Temperatures ◽

Structure Property ◽

Fluorescent Properties ◽

Metathesis Polymerization ◽

Good Thermal Stability ◽

Isolation And Characterization ◽

Selective Ring Opening

Selective ring-opening allene metathesis polymerization (ROAlMP) and ruthenium vinylidene formation from 1,2-cyclononadiene (1) by simple catalyst selection are discussed. Grubbs second generation catalyst (G2) favors the formation of an alkylidene leading to the ROAlMP of (1). Grubbs first generation catalyst (G1) favors vinylidene formation and prevents the homopolymerization of (1) even at elevated temperatures. Isolation and characterization of poly(1) by NMR analysis and MALDI-TOF confirms the generation of a well-defined polyallene that exhibits good thermal stability (TD ca. 400 ºC) and fluorescent properties. Ring-opening metathesis polymerization (ROMP) of a high strained norbornene derivative (NBE-iPr) at 80 ºC using the ruthenium vinylidene generated from (1) is also investigated. The discovery of ROAlMP allows for the simple accesses of well-defined polyallenes from commercially available catalysts and will ultimately guide structure-property determinations of polyallenes.

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Selective ring-opening metathesis polymerization (ROMP) of cyclobutenes. Unsymmetrical ladderphane containing polycyclobutene and polynorbornene strands

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.15.4 ◽

2019 ◽

Vol 15 ◽

pp. 44-51 ◽

Cited By ~ 3

Author(s):

Yuan-Zhen Ke ◽

Shou-Ling Huang ◽

Guoqiao Lai ◽

Tien-Yau Luh

Keyword(s):

Methyl Ester ◽

Ambient Temperature ◽

Ring Opening ◽

First Generation ◽

Double Bonds ◽

Ring Opening Metathesis Polymerization ◽

Metathesis Polymerization ◽

Selective Ring Opening ◽

Norbornene Derivatives

At 0 °C in THF in the presence of Grubbs first generation catalyst, cyclobutene derivatives undergo ROMP readily, whereas norbornene derivatives remain intact. When the substrate contains both cyclobutene and norbornene moieties, the conditions using THF as the solvent at 0 °C offer a useful protocol for the selective ROMP of cyclobutene to give norbornene-appended polycyclobutene. Unsymmetrical ladderphane having polycyclobutene and polynorbornene as two strands is obtained by further ROMP of the norbornene appended polycyclobutene in the presence of Grubbs first generation catalyst in DCM at ambient temperature. Methanolysis of this unsymmetrical ladderphane gives polycyclobutene methyl ester and insoluble polynorbornene-amide-alcohol. The latter is converted into the corresponding soluble acetate. Both polymers are well characterized by spectroscopic means. No norbornene moiety is found to be incorporated into polycyclobutene strand at all. The double bonds in the polycyclobutene strand are mainly in cis configuration (ca 70%), whereas the E/Z ratio for polynorbornene strand is 8:1.

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Multiblock Copolymers of Norbornene and Cyclododecene: Chain Structure and Properties

Polymers ◽

10.3390/polym13111756 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1756

Author(s):

Yulia I. Denisova ◽

Georgiy A. Shandryuk ◽

Marianna P. Arinina ◽

Ivan S. Levin ◽

Vsevolod A. Zhigarev ◽

...

Keyword(s):

First Generation ◽

Average Length ◽

Chain Structure ◽

Random Copolymers ◽

Multiblock Copolymers ◽

Structure Property ◽

Reaction Conditions ◽

Property Relations ◽

Cross Metathesis

We investigate the structure–property relations of the multiblock copolymers of norbornene with cyclododecene synthesized via the macromolecular cross-metathesis reaction between amorphous polynorbornene and semicrystalline polydodecenamer in the presence of the first-generation Grubbs catalyst. By adjusting the reaction time, catalyst amount, and composition of the initial system, we obtain a set of statistical multiblock copolymers that differ in the composition and average length of norbornene and dodecenylene unit sequences. Structural, thermal, and mechanical characterization of the copolymers with NMR, XRD, DSC (including thermal fractionation by successive self-nucleation and annealing), and rotational rheology allows us to relate the reaction conditions to the average length of crystallizable unit sequences, thicknesses of corresponding lamellas, and temperatures of their melting. We demonstrate that isolated dodecenylene units can be incorporated into crystalline lamellas so that even nearly random copolymers should retain crystallinity. Weak high-temperature endotherms observed in the multiblock copolymers of norbornene with cyclododecene and other cycloolefins could indicate that the corresponding systems are microphase-separated in the melt state.

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