Regioselective Ring-Opening Metathesis Polymerization of 3-Substituted Cyclooctenes with Ether Side Chains.

Abstract

Allyl-substituted cyclooctenes with ether side-chains [methoxy, methoxy-terminated oligo­(ethylene glycol)­s, and tetrahydrofurfuryloxy group] were prepared as monomers and polymerized by ring-opening metathesis polymerization (ROMP) using Grubbs second-generation catalyst. In all cases, the ROMP of allyl-substituted monomers proceeded in a regio- and stereoselective manner to afford polymers with remarkably high head-to-tail regioregularity with high trans-stereoregularity. The regio- and stereoregularity of polymers were affected by the bulkiness of the substituent, and the ROMP of tetrahydrofurfuryloxy-substituted cyclooctene exhibited nearly perfect regio- (head-to-tail = 99%) and stereoselectivity (trans-double bond = 99%). Chemical hydrogenation of obtained polymers afforded model poly­(ethylene-co-vinyl ether)­s with precisely placed ether branches on every eighth backbone carbon. Differential scanning calorimetry (DSC) was used to study the thermal properties, and the hydrophilicity of polymers was evaluated by water contact angle measurement. The surface hydrophilicity of unsaturated polymers was effectively tuned by changing the side-chain length of oligo­(ethylene glycol) groups while maintaining the hydrophobic character unchanged for saturated versions.

Polypentenamer Renaissance: Challenges and Opportunities

“…No thermal properties, such as semicrystallinity, were investigated, and no reports followed. The ability for allylic-substituted cis -cyclooctenes to influence both the direction of monomer insertion and the resulting cis / trans ratio of polyoctenamers from Ru catalysts was described by Kobayashi et al − …”

Ring-Opening Metathesis Polymerization of δ-Pinene: Well-Defined Polyolefins from Pine Sap

“…For all PδP samples, highly resolved signals with clear splitting patterns were observed within the 1 H NMR spectra and indicate a well-defined microstructure (Figure ). Asymmetric cycloalkenes with a significant steric difference on one side of the olefin have been shown to propagate in a highly regioregular fashion through ROMP. − The clear doublet-of-doublets seen for the olefin protons of each PδP sample is expanded in a 1 H– 1 H correlated NMR spectrum (COSY) (CDCl 3 , 25 °C) of ID 10 (Table ) in Figure D. Here we note that this is a representative example reflecting nearly identical outcomes observed for all polymers.…”

Olefin-Metathesis-Derived Norbornene–Ethylene–Vinyl Acetate/Vinyl Alcohol Multiblock Copolymers: Impact of the Copolymer Structure on the Gas Permeation Properties

“…The 13 C NMR spectrum of the E(N–COH)C2 copolymer in the CDCl 3 –DMSO-d6 (1:1 vol) mixture contained signals of the carbon atom linked to the HO-group (66–74 ppm, Figure S12 , similarly to [ 35 ]), whereas practically no signals of the carbon atoms in the epoxy group (56–62 ppm, Figure S12 ) were detected. New signals at 81.6 and 82.0 ppm ( Figure S12 ) were attributed to the carbon atoms in C–O–C, including C–O–CH 3 [ 40 ], formed as a result of the epoxy ring opening by sodium methylate in the presence of HCl. The same weak signals were observed in the 13 C NMR spectrum of E(N–COH)C1 ( Figure S12 ).…”