A family of homo- and heteroleptic zinc complexes bearing aminonaphtholate ligands was synthesized and fully characterized. Using NMR spectroscopy and DFT calculation, bis-alkoxy-bridged complexes [LZn(μ-OR)] were confirmed to have dimeric structures in solution, analogous to those obtained via X-ray crystallography. Surprisingly, a detailed experimental and theoretical study of the catalytic activity of [LZn(μ-OR)] in the ring-opening polymerization (ROP) of lactides showed that although well-defined alkoxy dimers possess a single-site structural motif, the most active initiator is obtained during in situ alcoholysis of the alkylzinc precursor. These results indicate that rational ancillary and alkoxy ligand design that takes into account its mutual interaction on monomer coordination may be key to the synthesis of new high-performance ROP catalysts.
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http://dx.doi.org/10.1021/acs.inorgchem.6b02439 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Graft-through ring-opening metathesis polymerization (ROMP) of norbornene-terminated macromonomers (MMs) prepared using various polymerization methods has been extensively used for the synthesis of bottlebrush (co)polymers, yet the potential of ROMP for the synthesis of MMs that can subsequently be polymerized by graft-through ROMP to produce new bottlebrush compositions remains untapped. Here, we report an efficient "ROMP-of-ROMP" method that involves the synthesis of norbornene-terminated poly(norbornene imide) (PNI)-based MMs that, following ROMP, provide new families of bottlebrush (co)polymers and "brush-on-brush" hierarchical architectures. In the bulk state, the organization of the PNI pendants drives bottlebrush backbone extension to enable rapid assembly of asymmetric lamellar morphologies with large asymmetry factors.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun, 130022, China.
The demand for insulating materials with superior dielectric properties has increased. Among these materials, polymers containing cyclic structure including cyclic olefin copolymer (COC) and cyclic olefin polymer (COP) stand out because of their excellent dielectric properties originating from the pure hydrocarbon structure. Introducing fluorine into polymers is one efficient strategy for optimizing the dielectric and the related important properties.
View Article and Find Full Text PDFDalton Trans
January 2025
Institut für Anorganische Chemie. Rheinische Friedrich-Wilhelms-Universität Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany.
Compared to aziridines, azaphosphiridines, which formally result from the replacement of a carbon atom by phosphorus, have been much less studied. In this work, accurate values for one of the most prominent properties, the ring strain energy (RSE), have been theoretically examined for a wide range of azaphosphiridine derivatives. Strongly related aspects of interest for developing the use of azaphosphiridines in heteroatom and polymer chemistry are ring opening reactions and polymerisations, the latter facilitated by their significantly high RSE.
View Article and Find Full Text PDFMacromol Rapid Commun
January 2025
Institut für Chemie, Technische Universität Chemnitz, Straße der Nationen 62, 09111, Chemnitz, Germany.
Aromatic diimides such as naphthalene diimide (NDI) and pyromellitic diimide (MDI) are important building blocks for organic electrode materials. They feature a two-electron redox mechanism that allows for energy storage. Due to the smaller size of MDI compared to NDI its theoretical capacity is higher.
View Article and Find Full Text PDFDes Monomers Polym
January 2025
Department of Physics Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran, Sumedang, Indonesia.
Polydimethylsiloxane (PDMS) is a polymer that can be used as a vitreous substitute. To fulfill the need for PDMS on a large scale, synthesis of PDMS in a large number is also needed. Therefore, intensive research is needed to produce PDMS in large quantities.
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