Inside Cover: Master of Chaos and Order: Opposite Microstructures of PCL‐co‐PGA‐co‐PLA Accessible by a Single Catalyst (Angew. Chem. Int. Ed. 11/2022)

Abstract

The iron guanidine catalyst …s hows extraordinary copolymerization activity towards lactide,g lycolide,a nd e-caprolactone,a sr eported by Sonja Herres-Pawlis,M oshe Kol, and co-workers in their Research Article (e202112853). Depending on the reaction temperature and the mode of monomer addition, it either forms up to pentablock copolymers in ah ighly defined way or promotes transesterifications to such ah igh degree that random copolymers are produced. Therefore,i ti sarare example of ac atalyst mastering both microstructures:o rdered and chaotic.

Sharing is Caring: Guidelines for Sharing in the Electronic Laboratory Notebook (ELN) Chemotion as applied by a Synthesis-oriented Working Group

“…We have chosen this example for two reasons: first, zinc complexes containing these ligands represent active catalysts in the ring-opening polymerization (ROP) of lactide. [44,45] However, the ligand system was passed to another PhD student via a joint database resulting in iron complexes which are even more active in the ROP [46,47] and, additionally, promote the combination of the ROP of lactide with the atom transfer radical polymerization (ATRP) of styrene. [48] Second, the ligand system was further modified in the backbone of the ligand.…”

Catalysts as Key Enablers for the Synthesis of Bioplastics with Sophisticated Architectures

“…Therefore, in the majority of events when CL is incorporated into the polymer chain, a transesterification occurs leaving an LA or GL active chain end that will incorporate the next CL monomer, since the LA and GL active chain end have a much lower tendency for transesterifications. Furthermore, it was found that the transesterifications preferably take place at the GL repeating unit possibly due to steric reasons [27] . It is astonishing that after more than five decades of lactone copolymerization still mechanistic features are revealed.…”

“…As the ROP with iron guanidine catalysts is a living polymerization following the coordination‐insertion mechanism, [13b,27] the growth of the PLA chain can be interrupted (and later resumed) for the formation of the active species accompanied with the iron(III) species. Since the duties of the iron(II) and iron(III) species are well separated, both polymerization mechanisms can work hand in hand without disturbing each other.…”

Sharing is Caring: Guidelines for Sharing in the Electronic Laboratory Notebook (ELN) Chemotion as applied by a Synthesis‐oriented Working Group**

“…We have chosen this example for two reasons: first, zinc complexes containing these ligands represent active catalysts in the ring‐opening polymerization (ROP) of lactide [45,46] . However, the ligand system was passed to another PhD student via a joint database resulting in iron complexes which are even more active in the ROP [47,48] and, additionally, promote the combination of the ROP of lactide with the atom transfer radical polymerization (ATRP) of styrene [49] . Second, the ligand system was further modified in the backbone of the ligand [46] .…”