Living Polymerization of Monomers Containing endo-Tricyclo[4.2.2.0^2,5]deca-3,9-diene Using Second Generation Grubbs and Hoveyda–Grubbs Catalysts: Approach to Synthesis of Well-Defined Star Polymers

Abstract

Living ROMP of monomers containing endo-tricyclo[4.2.2.02,5]deca-3,9-diene (TD) moieties was successfully performed using thermally stable second generation Grubbs and Hoveyda–Grubbs catalysts. Even slow-initiating catalysts enabled the living polymerization to give polymers with a narrow polydispersity index and controlled molecular weight because the unique structure of the TD monomers resulted in much faster initiation and slower propagation than conventional norbornene monomers. Kinetic analyses confirmed that the ratio of initiation/propagation rate (k i/k p) of the TD monomers was 10 to 200 times larger than that of norbornene derivatives. To demonstrate the living nature of the ROMP, block copolymers were successfully prepared using second generation Hoveyda–Grubbs catalyst for the first time. In addition, three-arm star polymers were prepared by core-first approach using Hoveyda–Grubbs type three-arm initiator, owing to the living ROMP of TD monomers with this stable catalyst. Also, star diblock copolymer was prepared with precise molecular weight and narrow PDI of 1.03. Since these star polymers contained bulky second or third generation dendrons, these dendronized three-arm star polymers were visualized under atomic force microscopy (AFM) to confirm the star-shape topology.

Spontaneous evolution of nanostructures by light‐driven growth of micelles obtained from in situ nanoparticlization of conjugated polymers

“…By combining the effects of the rigid shell and the time‐dependent expansion of the PCPV core, we designed and prepared another conjugated polymer that would also undergo spontaneous mesoscopic evolution under light by living ROMP and cyclopolymerization. Furthermore, the ROMP of endo ‐tricyclo[4.2.2.0]deca‐3,6‐diene (TD) derivatives has an advantage of allowing one‐shot copolymerization to form gradient or block‐like copolymers, because the catalyst preferentially reacts with the TD monomers . Various feed ratios of [ M2 ], [ M4 ], and [ G3 ] were screened for effective one‐shot gradient or block‐like copolymerization and INCP behavior (Table ).…”

Valorization of a CO2‐Derived Lactone by Acyclic Diene Metathesis Polymerization

“…Here, we take the advantage of substitution on the six‐membered ring in order to redistribute the olefinic groups by means of a metathesis catalyst and develop a new class of materials. The well‐known ruthenium based transition metal carbene complexes have witnessed an enormous utilization [15] in catalysing olefin metathesis reactions [16] . In this regard, the current work reports the state‐of‐the‐art ′ADMET′ (acyclic diene metathesis) polymerization of ( 1 ) (Scheme 1) in the presence of a phosphine free Hoveyda‐Grubb's II generation catalyst, where the Hoveyda chelate (ortho‐isopropoxy group) coordinates to the olefinic ends of the monomer generating the initiating species ( 3 & 4 ) and leading to the formation of the dimers ( 5 & 6 ) which may further react to form the oligomers ( 9 , 10 , 12 , 13 ) by different possible olefinic connections (Scheme 3).…”

“…The well-known ruthenium based transition metal carbene complexes have witnessed an enormous utilization [15] in catalysing olefin metathesis reactions. [16] In this regard, the current work reports the state-of-the-art 'ADMET' (acyclic diene metathesis) polymerization of (1) (Scheme 1) in the presence of a phosphine free Hoveyda-Grubb's II generation catalyst, where the Hoveyda chelate (ortho-isopropoxy group) coordinates to the olefinic ends of the monomer generating the initiating species (3 & 4) and leading to the formation of the dimers (5 & 6) which may further react to form the oligomers (9, 10, 12, 13) by different possible olefinic connections (Scheme 3). The reaction mechanism for the contemporary ADMET polymerization has been proposed and elucidated by 13 C-NMR and 1 H-NMR spectroscopic analysis.…”

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…91) [390,391]; (11) a stilbene-carbonate bridged macrocycle (e.g. 92) [392]; (12) [2.2]paracyclophanes (e.g.…”