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A study of the structure and morphology of diblock copolymers composed of crystallizable blocks of polyethylene (PE) and syndiotactic polypropylene (sPP) having different lengths is reported. In both analyzed samples, the PE block crystallizes first by cooling from the melt (at 130 °C) and the sPP block crystallizes after at a lower temperature. Small angle X-ray scattering (SAXS) recorded during cooling showed three correlation peaks at values of the scattering vector, q1 = 0.12 nm−1, q2 = 0.24 nm−1 and q3 = 0.4 nm−1, indicating development of a lamellar morphology, where lamellar domains of PE and sPP alternate, each domain containing stacks of crystalline lamellae of PE or sPP sandwiched by their own amorphous phase of PE or sPP. At temperatures higher than 120 °C, when only PE crystals are formed, the morphology is defined by the formation of stacks of PE lamellae (17 nm thick) alternating with amorphous layers and with a long period of nearly 52 nm. At lower temperatures, when crystals of sPP are also well-formed, the morphology is more complex. A model of the morphology at room temperature is proposed based on the correlation distances determined from the self-correlation functions extracted from the SAXS data. Lamellar domains of PE (41.5 nm thick) and sPP (8.2 nm thick) alternate, each domain containing stacks of crystalline lamellae sandwiched by their own amorphous phase, forming a global morphology having a total lamellar periodicity of 49.7 nm, characterized by alternating amorphous and crystalline layers, where the crystalline layers are alternatively made of stacks of PE lamellae (22 nm thick) and thinner sPP lamellae (only 3.5 nm thick).

Stereoselective propene polymerization mechanisms promoted by C1-symmetric transition metal (TM) catalysts with nonmetallocene and ansa-metallocene ligands have been revisited by density functional theory (DFT) calculations combined with a molecular descriptor for steric analysis (%VBur) and a state-of-the-art interpretative tool based on the Activation Strain Model (ASM) and a Natural Energy Decomposition Analysis (NEDA). While DFT results suggested a close similarity for mechanisms and stereoselectivities for these catalyst classes, the ASM-NEDA analysis unraveled that different stereoelectronic effects play the dominant role depending on the ligand framework. The insights achieved by such analysis on the "naked"cationic active species were also confirmed by adding the counterion in the calculations, thus allowing a better understanding of olefin polymerization mechanism(s) governed by TM catalysts.

The mechanisms for the formation of N-substituted hydrazones by coupling of alcohols and hydrazine, achieved by the sequential processes of acceptorless dehydrogenation and borrowing hydrogen, has been unveiled by density functional theory (DFT) calculations. The release of water and molecular hydrogen as subproducts, combined with the Mn-PNN pincer based catalyst describe a green environment. Mechanistically, apart from describing a complex system of three coupled catalytic pathways, calculations describe the pivotal role of two intermediates, which participate in two catalytic pathways each one. Finally, predictive catalysis plays the role to push forward this reaction toward milder conditions, and thus in line with green chemistry standards A.P. is a Serra Húnter Fellow and ICREA Academia Prize 2019. S.S. and A.P. thank the Spanish MINECO for projects and PID2020-113711GB-I00 and PGC2018-097722-B-I0 Open Access funding provided thanks to the CRUE-CSIC agreement with Wiley