Rapid Syndiospecific (Co)Polymerization of Fluorostyrene with High Monomer Conversion

Abstract

Fluoromonomers are difficult to polymerize through a coordination mechanism owing to the strong chelation between fluorine and catalysts and the electron-deficient double-bond. We report herein the unprecedented polymerization of para-fluorostyrene (pFS) with excellent activity (1.12×10 g mol h ), distinguished syndioselectivity (rrrr >99 %) and high conversion (98.4 %) using rare-earth-metal catalysts bearing a pyridyl methylene fluorenyl ligand. DFT calculations reveal polar fluorine loses overwhelming coordination priority to the active central metal ion due to the sterically bulky and electron-donating CGC-ligand, thus its power of poisoning the active species is dramatically weakened. Based on this, copolymerization of pFS and styrene (St) has been successfully achieved with high activity and controllable pFS insertion. Conversely, the unlinked half-sandwich rare-earth-metal system shows relatively lower activity, because both the transition-states and intermediates incorporate a μ -F chelated pFS.

Syndio-and cis-1,4 dually selective copolymerization of polar fluorostyrene and butadiene using rare-earth metal catalysts

“…First, the copolymerization of p-fluorostyrene ( pFS) and butadiene (BD) in toluene at room temperature was investigated by using the catalytic systems of 1/[Ph 3 C][B(C 6 F 5 ) 4 ]/[Al i Bu], which are highly active towards the homopolymerization of pFS and the copolymerization with styrene and ethylene, respectively. 25,26 The polymerization catalyzed by 1a (Flu cent -Sc-N (96.26°)) occurred fast but gave a copolymer insoluble in many solvents even under a high temperature of 160°C. We proposed that cross-linking took place, since the scandium active species is Lewis acidic and can initiate polymerization of the dangling CvC bonds of the 1,2-regulated PBD segments.…”

“…[20][21][22] We reported for the first time the coordination homo-and copolymerizations of polar styrene monomers including methoxystyrene (MOSt) and halogen substituted styrenes with the use of side-armed half-sandwich rare-earth metal complexes, with styrene exhibiting high activity and stereoselectivity. [23][24][25] Thereafter copolymers composed of polar styrenes/ethylene and anisylpropylenes/ethylene were obtained. [26][27][28] With respect to polar dienes, copolymerization of 2-(2-methylidenebut-3-enyl)furan (MBEF) with isoprene without a masking reagent was achieved by using the bis ( phosphino)carbazolideyttrium precursor.…”

Syndioselective Polymerization of Vinylnaphthalene

“…Since then, extensive studies have been devoted to develop efficient “single‐site” catalytic systems for stereospecific polymerization of styrene and its derivatives, and various homogeneous metallocene, half‐metallocene, and non‐metallocene group 3 and 4 metal‐based catalysts have been invented . In the meantime, syndiotactic polystyrene derivatives bearing polar groups such as halogen, alkoxyl, aminoalkyl, and methylthio etc., that provide polymers with improved surface properties, adhesive properties, affinity for dyes, and compatibility with other polar polymers, have been successfully prepared …”

“…Recently, we found that rare‐earth metal catalysts supported by pyridyl methyl fluorenyl ligand demonstrated their superiority on selective and controlled coordination polymerization of styrene derivatives bearing various electron‐donating/withdrawing substituents . With the help of these powerful constrained geometry configuration (CGC) catalysts, we successfully synthesized a series of high syndiotactic polystyrene derivatives such as poly(methoxystyrene), poly(4‐Methylthiostyrene), poly(4‐fluorostyrene) etc . In this contribution, we report that coordination polymerizations of 1VN, 2VN, and MVN were carried out by using the half‐sandwich scandium precursor 1 and the CGC rare‐earth metal precursors 2a ‐ 2c ( Figure ).…”

Stereoselective Polymerization of an Aromatic Vinyl Monomer to Access Highly Syndiotactic Poly(vinyl alcohol)

“…Recently, rare‐earth metal based catalytic systems have been reported to be extraordinary tolerance toward polar groups, which exhibit high activity and excellent stereo‐selectivity for homo‐ and copolymerizations of polar styrenes. [ 17,18,27–34 ] We report herein the coordination polymerization of BN2VN using a series of half‐sandwich or constrained‐geometry‐configuration (CGC)‐type scandium catalysts ( Figure ) with high activity and distinguished syndioselectivity to give high molecular weight products, which can be transferred to highly syndiotactic poly(vinyl alcohol). The influences of steric hindrance of ligands and polymerization conditions on the catalyst performances as well as structures of the resultant products are investigated.…”