The copolymerization of renewable monomers such as ocimene (O), myrcene (M), and farnesene (F) with butadiene (B), promoted by dichloro{1,4-dithiabutanediyl-2,2′-bis [4,6-bis(2phenyl-2-propyl)phenoxy]}titanium (1) activated by modified methylalumoxane (m-MAO) under mild reaction conditions, was investigated. Copolymers in a wide range of compositions were obtained through a judicious control of the alimentation feed (up to 85% of terpene incorporated in the case of poly(ocimene− butadiene) (POB)). Analysis of POB, poly(myrcene−butadiene) (PMB), and poly(farnesene−butadiene) (PFB) microstructures revealed the good stereoselectivity of 1, both in the butadiene (up to 95%) and in the terpene (up to 92%, 71%, and 86% for O, M, and F, respectively) insertion. For all these new materials, a complete 13 C NMR assignment was performed, revealing a multiblock structure. A sample of POB was also evaluated as a component in a model tread compound leading to improved mechanical properties with respect to the corresponding plain butadiene rubbers.

The growing environmental pollution and the expected depleting of fossil resources have sparked interest in recent years for polymers obtained from monomers originating from renewable sources. Furthermore, nature can provide a variety of building blocks with special structural features (e. g. side groups or stereo-elements) that cannot be obtained so easily via fossilbased pathways. In this context, terpenes are widespread natural compounds coming from non-food crops, present in a large variety of structures, and ready to use as monomers with or without further modifications. The present review aims to provide an overview of how chemists can stereospecifically polymerize terpenes, particularly the acyclic ones like myrcene, ocimene, and farnesene, using different metal catalyst systems in coordination-insertion polymerization. Attention is also paid to their copolymers, which have recently been disclosed, and to the possible applications of these bio-based materials in various industrial sectors such as in the field of elastomers.

Soluble heterocomplexes consisting of sodium hydride in combination with trialkylaluminum derivatives have been used as anionic initiating systems at 100 °C in toluene for convenient homo-, co- and ter-polymerization of myrcene with styrene and isoprene. In this way it has been possible to obtain elastomeric materials in a wide range of compositions with interesting thermal profiles and different polymeric architectures by simply modulating the alimentation feed and the (monomers)/(initiator systems) ratio. Especially, a complete study of the myrcene-styrene copolymers (PMS) was carried out, highlighting their tapered microstructures with high molecular weights (up to 159.8 KDa) and a single glass transition temperature. For PMS copolymer reactivity ratios, rmyr = 0.12 ± 0.003 and rsty = 3.18 ± 0.65 and rmyr = 0.10 ± 0.004 and rsty = 3.32 ± 0.68 were determined according to the Kelen–Tudos (KT) and extended Kelen–Tudos (exKT) methods, respectively. Finally, this study showed an easy accessible approach for the production of various elastomers by anionic copolymerization of renewable terpenes, such as myrcene, with commodities.

Coupling of CO2 with epoxides is a green emerging alternative for the synthesis of cyclic organic carbonates (COC) and aliphatic polycarbonates (APC). The scope of this work is to provide a comprehensive overview of metal complexes having sulfur-containing ligands as homogeneous catalytic systems able to efficiently promote this transformation with a concise discussion of the most significant results. The crucial role of sulfur as the hemilabile ligand and its influence on the catalytic activity are highlighted as well.

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