Polymerization of Bio‐Derived Conjugated Dienes with Rare‐Earth‐Metal Complexes

Abstract

The reliance of both our life and industry on fossil resource and the alarming accumulation of polymeric materials in the environment have presented huge challenges to sustainable society. Nowadays, utilization of renewable monomers as building blocks for polymeric materials has emerged as a hot topic and increasingly gained attention from chemists. As a class of biomass with abundance and low cost, terpenes are typical hydrocarbon‐rich natural compounds, and some of them, such as myrcene and farnesene, are inherently suitable for coordination polymerization. In this review, we focus on the rare‐earth metal catalyzed highly regio‐ and stereoselective polymerization of bio‐based conjugated dienes, especially the ones from terpene‐derived compounds with or without modifications. This review also discusses the future direction on the modification of these bio‐based conjugated dienes.

Living cis-1,4-Selective Polymerization of 1,3-Dienes by Enamino-Oxazolinate Rare-Earth Metal Complexes

“…Therefore, the catalytic performances of yttrium complexes, namely, 1-Y , 2-Y , 3-Y , and 4-Y , in the polymerization of Myr and Far were investigated briefly at room temperature (Table ). , The 1-Y /[Ph 3 C]­[B­(C 6 F 5 ) 4 ] catalytic system could polymerize 500 equiv of Myr with a yield of 57.3% within 5 min and further reach quantitative conversion in 10 min. The afforded polymers had high molecular weights (13.9 × 10 4 g mol –1 ) and narrow molecular weight distributions ( M w / M n = 1.08).…”

“…However, relatively fewer research studies have been conducted on their (especially Far) polymerization compared to isoprene. 37 Therefore, the highly cis-1,4-selective polymerization of Myr (up to 99.6% cis-1,4) and Far (up to 99.9% cis-1,4) catalyzed by enamino-oxazolinate rare-earth metal complexes was also investigated in this work. −CF 3 group in the ligands, the NMR spectra of the corresponding rare-earth metal complexes evidenced the absence of byproducts caused by their decomposition, and all the obtained complexes were stable in their solid state for at least a month at −30 °C.…”

“…As directly available natural conjugated dienes, β-myrcene (Myr, 7-methyl-3-methylene-octa-1,6-diene, C 10 H 16 ) and β-farnesene (Far, 7,11-dimethyl-3-methylene-1,6,10-dodecatriene, C 15 H 24 ) are, respectively, dimers and trimers of isoprene with long side chains linked to the polymerizable diene unit, which have promising applications in the development of new materials for green tires. However, relatively fewer research studies have been conducted on their (especially Far) polymerization compared to isoprene . Therefore, the highly cis -1,4-selective polymerization of Myr (up to 99.6% cis -1,4) and Far (up to 99.9% cis -1,4) catalyzed by enamino-oxazolinate rare-earth metal complexes was also investigated in this work.…”

Rare-earth-metal catalyzed highly regio- and stereoselective polymerization of terpene-derived conjugated dienes

“…On the other hand, rare-earth metal catalyzed coordination polymerization represents a promising alternative strategy for the polymerization of terpenes and their derivatives with a conjugated diene unit, especially for controlling the regularity of polymers. 11 In theory, the inherent structural features of terpenes (with the molecular formula (C 5 H 8 ) n ) make them and their well-designed derivatives with a conjugated diene unit suitable for rare-earth metal catalyzed coordination polymerization. Readily available natural isoprenoids (compounds derived from the isoprene building block, such as β-myrcene (Myr) and β-farnesene (Far)) could be converted into polymers with diverse microstructures ( cis -1,4, trans -1,4 and 3,4-) by rare-earth metal catalysts.…”

Rare-earth-metal-catalyzed highly 3,4-regioselective polymerization of polar 1-phenyl-1,3-butadiene derivates

“…Diverse well-designed 1,3-dienes have been synthesized and ultimately studied to afford polymers with versatile properties and wide application over past decades. 7,8 As a substituted derivative of 1,3-butadiene, 1-phenyl-1,3-butadiene ( 1PB ) exhibited rather different polymerization features, and also represented a challenging monomer for polymerization due to the delocalization characteristic and steric bulkiness of the phenyl substituent significantly affecting the activity of the attached conjugated diene moiety. 1PB could be conveniently synthesized via the Wittig-olefination reaction, and its structure was also easily tailored with different substituents on the aromatic ring.…”