Publications (169) View all
-
Article: Synthesis of functional 'polyolefins': state of the art and remaining challenges.
[show abstract] [hide abstract]
ABSTRACT: Functional polyolefins (i.e., polyethene or polypropene bearing functional groups) are highly desired materials, due to their beneficial surface properties. Many different pathways exist for the synthesis of these materials, each with its own advantages and drawbacks. This review focuses on those synthetic pathways that build up a polymer chain from ethene/propene and functionalised polar vinyl monomers. Despite many recent advances in the various fields of olefin polymerisation, it still remains a challenge to synthesise high molecular-weight copolymers with tuneable amounts of functional groups, preferably with consecutive insertions of polar monomers occurring in a stereoselective way. To overcome some of these challenges, polymerisation of alternative functionalised monomers is explored as well.Chemical Society Reviews 04/2013; · 28.76 Impact Factor -
Article: A Noble-Metal-Free System for Photodriven Catalytic Proton Reduction.
[show abstract] [hide abstract]
ABSTRACT: Who needs the nobles? Ideally, devices to harvest solar energy into fuels would, in addition to having very high turnover numbers, make use of earth-abundant materials. In this Highlight we focus on a recent example in which a copper-based photosensitizer is used, in combination with an iron-based catalyst for light-driven proton reduction.ChemSusChem 03/2013; · 6.83 Impact Factor -
Article: Supramolecular Control of Selectivity in Hydroformylation of Vinyl Arenes: Easy Access to Valuable β-Aldehyde Intermediates.
[show abstract] [hide abstract]
ABSTRACT: Go against the flow! A rationally designed regioselective hydroformylation catalyst, [Rh/L], in which noncovalent ligand-substrate interactions allow the unprecedented reversal of selectivity from the typical α-aldehyde to the otherwise unfavored product β-aldehyde, is reported. This catalytic system opens up novel and sustainable synthetic pathways to important intermediates for the fine-chemicals industry.Angewandte Chemie International Edition 02/2013; · 13.45 Impact Factor -
Article: A different route to functional polyolefins: olefin-carbene copolymerisation.
[show abstract] [hide abstract]
ABSTRACT: Copolymerisation of carbenes and olefins (ethene), mediated by Rh-based catalyst precursors, is presented as a new, proof-of-concept methodology for the controlled synthesis of functional polymers. The reactions studied show that olefin-carbene polymerisation reactions provide a viable alternative to more traditional olefin polymerization techniques. Rh(III)-catalyst precursors, while active in the homopolymerisation of either olefins or carbenes, proved to be virtually inactive in olefin-carbene copolymerization. Conversely, the use of Rh(I)(cod) catalyst precursors allows the synthesis of high molecular-weight, highly functionalized copolymers. The reactions yield a mixture of copolymers and some carbene homopolymers, which proved to be difficult to separate. Polyethylene was not formed under the applied reaction conditions. The average ethene content in this mixture could be increased up to 11%, although analysis of the mixture revealed that the ethene content in fractions of the copolymer mixture can be as high as 70%. Attempts to increase the ethene content by increasing the ethene pressure unexpectedly led to lower average ethene contents, which is most likely due to changes in the ratio of copolymers vs. carbene homopolymer. This behaviour is most likely a result of the reactivity difference of different active Rh-species formed under the applied reaction conditions. Apparently, higher ethene concentrations slow down the copolymerisation process (mediated by yet unidentified Rh-species) compared to the formation of homopolymers (mediated by different Rh-catalysts; most likely (allyl)Rh(III)-alkyl species), thereby changing the product ratio in favour of the homopolymer. The average ethene content in the copolymer mixture therefore decreases, while the ethene content within the copolymer fraction has likely increased at higher ethene concentrations (but simply less copolymer is formed). The obtained copolymers exhibit a blocky microstructure, with the functional blocks being highly stereoregular. Branching does occur and the functional groups are present in the polymer backbone as well as at the branches. Formation of copolymers was confirmed by Maldi-ToF analysis, which revealed incorporation of several ethene units into the copolymers.Dalton Transactions 01/2013; · 3.84 Impact Factor -
Article: Regioselective Pd-catalyzed hydroamination of substituted dienes
Catalysis Science & Technology 01/2013; 3(5):1375.
