Hydrogenated Ring-Opened Poly(endo-dicyclopentadiene)s Made via Stereoselective ROMP Catalyzed by Tungsten Complexes:  Crystalline Tactic Polymers and Amorphous Atactic Polymer

Abstract

Properties of the tactic and atactic hydrogenated ring-opened poly(endo-dicyclopentadiene)s and features of the tungsten imido/phenolate-catalyzed stereoselective ring-opening metathesis polymerizations (ROMP) were studied. Several tungsten(VI) imido phenolate complexes were synthesized and exhibited moderate ROMP activity in the presence of n-BuLi. W(dNPh)((R)-(+)-5,5′,6,6′-Me 4 -3,3′-t-Bu 2 -biphenolate) 2 was found to be effective for cis-, isoselective ROMP of endo-dicyclopentadiene (DCPD), while W(dNPh)Cl 4 ‚Et 2 O promoted cis-, syndioselective ROMP. On the other hand, W(dNPh)(2,6-Me 2 -phenolate) 4 provided atactic poly(DCPD). Isotactic, atactic, and syndiotactic hydrogenated ring-opened poly(DCPD)s were characterized well by various methods for the first time. Both tactic polymers were shown to be crystalline polymers by means of DSC, WAXD, and TEM measurements. In contrast, atactic poly(DCPD) was an amorphous polymer. The crystallization rate of the syndiotactic hydrogenated poly(DCPD) was significantly higher than that of the isotactic polymer.

Addition Oligomerization of Dicyclopentadiene: Reactivity of Endo and Exo Isomers and Postmodification

“…Hydrogenation of unsaturated cyclic olefin polymers has been largely employed as a means of eliminating the long‐term instability of the polymers exposed to air . Hydrogenation was performed with diimine generated in situ via thermal decomposition of p‐ TsNH, according to the procedure reported in literature .…”

Synthesis and ROMP activity of aminophenol-substituted tungsten(VI) and molybdenum(VI) complexes

“…The resultant organometallic intermediate would then undergo an a-elimination reaction to give the corresponding alkylidene complex. Recently, W and Mo complexes with chelating aryloxo ligands have attracted attention as very active catalyst precursors for controlled ROMP [7][8][9]. Especially, W(VI) phenolate complexes with additional oxo and imido ligands were reported as precursors for highly efficient as well as highly stereoselective ROMP catalysts [9].…”

Increasing the oxidative stability of poly(dicyclopentadiene) aerogels by hydrogenation

“…30 to 300 mg mL The drawback of pDCPD materials is that the high density of alkenes along the polymer backbone makes this material susceptible to oxidative damage. 18 In many cases, the preparation of pDCPD polymers is coincident with the formation of small amounts of oxidation products along the polymer. In the case of solid pDCPD films, the oxidation process forms an oxide film that prevents further oxidation of the inner material 19 ; this is likely not the case for an aerogel wherein the material porosity is larger than 90 % and an outer, oxide film will not inhibit oxidation of the inner domains.…”