In: Acta Crystallographica Section B, 2012, vol. 68, no. 2, p. 171-181
Ab-initio crystal structure analysis of organic materials from electron diffraction data is presented. The data were collected using the automated electron diffraction tomography (ADT) technique. The structure solution and refinement route is first validated on the basis of the known crystal structure of tri-p-benzamide. The same procedure is then applied to solve the previously unknown crystal...
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In: Macromolecules, 2013, vol. 46, no. 14, p. 5520–5530
The synthesis of perfectly planar, bis-substituted aromatic polyamides is reported herein. With highly flexible triethylene glycol chains attached and conformational restriction through intramolecular, bifurcated hydrogen bonds these are among the most shape-persistent yet organo-soluble polymers to date. Starting from 4-nitrosalicylic acid, our group developed a route to phenyl-2,5-bis-TEGylated...
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In: Macromolecular Rapid Communications, 2016, vol. 37, no. 6, p. 532–538
Today's olefin metathesis catalysts show high reactivity, selectivity, and functional group tolerance and allow the design of new syntheses of precisely functionalized polymers. Here the synthesis of a new end-capping reagent is investigated allowing the introduction of a highly reactive activated ester end-group at the polymer chain end as well as its prefunctionalization to directly...
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In: Angewandte Chemie International Edition, 2019, vol. 58, no. 43, p. 15278–15282
A recently developed catalytic living ring opening metathesis polymerisation (ROMP) was investigated using a series of reversible chain transfer agents (CTA) carrying either cyclopentene or cyclohexene rings, differing only in ring strain. All cyclopentene derivatives examined showed significantly faster reaction rates than the corresponding cyclohexene derivatives. This resulted in lower...
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In: Nature Chemistry, 2015, vol. 7, no. 9, p. 718–723
In living ring-opening metathesis polymerization (ROMP), a transition-metal–carbene complex polymerizes ring-strained olefins with very good control of the molecular weight of the resulting polymers. Because one molecule of the initiator is required for each polymer chain, however, this type of polymerization is expensive for widespread use. We have now designed a chain-transfer agent (CTA)...
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In: Nature Chemistry, 2019, vol. 11, no. 5, p. 488–494
In a conventional living ring-opening metathesis polymerization (ROMP), an equal number of ruthenium complexes to the number of polymer chains synthesized are required. This can lead to high loadings of ruthenium complexes when aiming for shorter polymers. Here, a reversible chain-transfer agent was used to produce living ROMP polymers from norbornene derivatives using catalytic amounts of...
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In: ACS Nano, 2013, vol. 7, no. 6, p. 5491–5498
Molecular self-assembly on surfaces is dictated by the delicate balance between intermolecular and molecule–surface interactions. For many insulating surfaces, however, the molecule–surface interactions are weak and rather unspecific. Enhancing these interactions, on the other hand, often puts a severe limit on the achievable structural variety. To grasp the full potential of molecular...
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In: Journal of Polymer Science Part A: Polymer Chemistry, 2016, vol. 54, no. 9, p. 1236–1242
In an attempt to introduce monomer sequence control in a growing polynorbornene via ring-opening metathesis polymerization, we employ dioxepins to efficiently determine the location of the monomers on the macromolecule backbone. Owing to the acid-labile acetal group, dioxepins allow scission of the polymer at the point of the dioxepin insertion and thus provide an indirect way to determine...
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In: CHIMIA International Journal for Chemistry, 2012, vol. 66, no. 3, p. 99-103
In this article we present a review of our recent results in one area of research we are involved in. All research efforts in our group focus on functional polymers and new ways of gaining higher levels of control with regard to the placement of functional groups within these polymers. Here, the living ring opening metathesis polymerization (ROMP) will be reviewed for which...
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In: Macromolecules, 2012, vol. 45, no. 11, p. 4447–4453
An efficient strategy for the synthesis of monoamine end-functionalized living polymers using ring-opening metathesis polymerization with ruthenium initiators is reported. A new end-capping agent for this purpose was synthesized, and its efficiency for end-functionalization was evaluated using two common ruthenium-based initiators. Finally, terminal cross-metathesis was also explored as...
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