Stereospecific Ring-Opening Metathesis Polymerization of Cycloolefins Using Novel Molybdenum and Tungsten Complexes Having Biphenolate Ligands. Development of Crystalline Hydrogenated Poly(endo-dicyclopentadiene) and Poly(norbornene)

Abstract

Novel molybdenum-and tungsten-based catalysts induced stereospecific ring-opening metathesis polymerization (ROMP) of cycloolefins to produce a new class of crystalline polymers. Various monomeric molybdenum(VI) and tungsten(VI) complexes of the general formula M()O)(O-Ar) 4 (M ) Mo or W;(O-Ar)4 is two biphenolate or four phenolate ligands) were prepared. These catalysts exhibited moderate ROMP activity in the presence of cocatalyst such as n-BuLi and Et3Al. The molybdenum and tungsten complexes bearing substituted biphenolate ligands such as oxomolybdenum(VI) bis(racemic-5,5′,6,6′-tertamethyl-3,3′-di-tert-butyl-1,1′-biphenyl-2,2′-diolate) promoted cis and isospecific ROMP of endodicyclopentadiene (cis > 90% and meso > 95%). The novel ternary and quarternary catalysts such as MoOCl 4-biphenolate-n-BuLi (1:2:2) were developed as a new useful methodology to control the stereoselectivity of the ROMP. Hydrogenation of the cis-isotactic poly(endo-dicyclopentadiene)s and poly-(norbornene)s provided novel crystalline polymers with high melting points (295 °C, ∆H ) 50 J/g; 175 °C, ∆H ) 60 J/g, respectively), which can be regarded as a new class of crystalline polymers.

Synthesis and characterization of poly(ε-caprolactone) and copolyesters by catalysis with molybdenum compounds: polymers with acid-functional asymmetric telechelic architecture

“…Molybdenum is a versatile element present in many catalytic systems used for polymerization, such as those utilized for the polymerization of norbornenes [10,11] and phenylacetylene [12]. However, there are few reports related to the use of molybdenum derivatives in ROP of lactones.…”

Polyolefins containing 1,3‐disubstituted cyclopentane units as nucleating agents for isotactic polypropylene

“…The difference in the T m of PCP1-3 should be derived from the difference in stereo-regularity of the each fraction. (Note: It is impossible to determine the stereo-regularity of PCP by means of 13 C NMR spectroscopy). The T m of PCP4, which was obtained with catalyst 2, was 2308C.…”

“…13,14 In this study, we investigated the effect of structure of polyolefins containing 1,3-cyclopentane units on the nucleation of PP.…”

ortho‐Selective Phenol‐Coupling Reaction by Anodic Treatment on Boron‐Doped Diamond Electrode Using Fluorinated Alcohols

“…[2] Recently, biphenols based on simple methyl-substituted phenols, for example, 2,4-dimethylphenol have drawn significant attention as components of highly potent ligand systems. [3][4][5] The sustainable synthesis of such biphenols is challenging despite their rather simple scaffolds. Methyl-substituted phenols are prone to side reactions and 2,4-dimethylphenol in particular results in predominantly polycyclic architectures upon anodic treatment.…”