We have been granted an exclusive interview with Viktoria Gessner, leader of the Gessner Research Group and chair of Inorganic Chemistry at Ruhr-Bochum University, following the acquisition of the YPhos ligand technology by Umicore.
Could you describe your YPhos ligands and what makes them unique, compared to other phosphine ligands available?
YPhos ligands are phosphine ligands that have an ylide substituent rather than an aryl or alkyl substituent as you’d normally expect. This substituent features a carbon atom with a negative charge next to phosphorus, which makes the ligands uniquely electron rich.
Since these catalysts are more electron rich than the usual alkylphosphines available on the market, there are many catalytic applications that benefit from their use, including both palladium and gold catalysis reactions. Monoligated palladium YPhos complexes, for example, can be used in coupling chemistries, (C-C and C-N bond-forming reactions) and exhibit high activities.1These reactions are particularly relevant because they’re the kind that are done in the fine chemical industry in the production of pharmaceuticals and agrochemicals.
Additionally, in gold catalysis, YPhos ligands show higher activity in both hydroamination reactions and also in more specialised C-H, C-C bond-forming and cyclisation reactions.2
What drove you towards this area of chemistry, both in terms of both personal interest and figures that have inspired you?
我真的很感兴趣地了解配体的结构 - 更具体地说是它们的结构活动关系。这也反映在YPHOS配体中，因为，以及具有特殊的供体性，配体也具有非常美丽的建筑。这是这种独特的结构，实际上通过培养配体和金属之间的额外相互作用来促进催化剂稳定性。因此，它并不完全是它的捐助性质，使他们尽可能强大，而是他们的整个建筑。当我们为不同的目的开发了yphos配体，这很重要，我们不仅看着捐助者的力量，而且还有空间需求。
In terms of figures who inspire me, Chadwick Tolman really was one of the pioneers who started characterising ligands and really tried to understand structure–activity relationships. He also began giving parameters to ligands and understanding them in terms of coordination chemistry.
it’s my philosophy that happy co-workers are the best co-workers
To develop these ligands, you worked with Umicore. What did you find were some of the benefits that came about by working closely with industry?
The main benefit that I found was getting a different viewpoint into my research. Normally, in academia, you rely mostly on publications from other academics who only sometimes look at the industrial perspective to a piece of research. I’ve found it’s better to have direct contact with someone who really knows about the ins and outs of the current needs of industry and what the environment you’re working to supply is like. This can really help facilitate your development process and help you understand which direction to take your research.
Your team has been responsible for several innovations. How do you facilitate this kind of effective working environment?
Separately from this, I also try to create a lot of diversity within the group in terms of research areas. My group is divided into two different types of chemistry: one more focused on reactive compounds and one which investigates catalysis, but I think they can both learn a lot from each other, especially in terms of isolating intermediates and catalysts.
I also ensure that my PhD students have access to all the instruments and good working conditions – dedicating a lot of time to optimising the infrastructure for them as much as I can.
It was clear to me that I wanted to go into chemistry from quite early on. I was always asking ‘why does this work as it does?’ and felt that chemistry was the field that answers this question best. Then during my PhD thesis, I began to notice that research in academia was something that I really enjoyed doing.
I spoke about structure–activity relationships, which I think is something that is really going to change with the advent of machine learning. I am thinking about going into machine learning because that really feels like the future of the field
I obtained my PhD atTU Dortmund与我的博士监督员一起搬家后University of Würzburg。我的博士学博士最初专注于有机锂化学和高度反应性化合物，而是在我在加利福尼亚大学的伯克利大学的博士后，我开始转向超分子化学。到目前为止，我热衷于开始我的住身。所以，我回到了Würzburg，经过五年后，我接到了Ruhr-of Bochum的呼吁，我现在正在坐在无机化学的椅子上。
Where do you see this area of chemistry going in the future?
I spoke about structure–activity relationships, which I think is something that is really going to change with the advent of machine learning. I am thinking about going into machine learning because that really feels like the future of the field. We have this modularity in our ligands and several positions we can change to meet the requirements of the substrates, but it’s not always easy to predict. Machines could change all of this by obtaining all the parameters in terms of both donor strength and sterics. If we can get enough parameters, we will be able to much more quickly develop ligands for specific applications.
这不是一个非常新的领域的化学——它年代tarted almost 20 years ago in areas like pharmaceuticals, and they have been using it to predict binding properties for many years now. But from the looks of things, some groups in the USA and Europe have begun using it in molecular chemistry, so we’ll probably see more of that in the next few years.
1. See, for example:
- T. Scherpf, H. Steinert, A. Großjohann, K. Dilchert, J. Tappen, R. Rodstein, V. H. Gessner, Efficient Pd-Catalyzed Direct Coupling of Aryl Chlorides with Alkyllithium Reagents,angew。化学。Int。艾德。2020.,59, 20596-20603
- I. Rodstein, J. Tappen, K. McGuire, A. Großjohann, J. Löffler T. Scherpf, V. H. Gessner Palladium Complexes based on Ylide-Functionalized Phosphines (YPhos): Broadly Applicable High-Performance Precatalysts for the Amination of Aryl Halides at Room Temperature,化学。Eur. J.2020.,26, 4281
- L.T.Scharf，I. Rodstein，M.Schmidt，T.Scherpf，V.H. Gessner，解开钯催化的胺化反应中的ylide官能化磷酸的高活性：对比研究Cy约翰·斯科斯和帕tBu3,ACS Catal。2020.,10, 999-1009
- P. Weber, T. Scherpf, I. Rodstein, D. Lichte, L. T. Scharf, L. J. Gooßen, V. H. Gessner, A Highly Active Ylide-Functionalized Phosphine for Palladium-Catalyzed Aminations of Aryl Chlorides, Angew。化学。Int。艾德。2019年,583203-3207。
2. See, for example:
- J. Handelmann, C.N. Babu, H. Steinert, C. Schwarz, T. Scherpf, A. Kroll and V.H. Gessner, Towards the Rational Design of Ylide-Substituted Phosphines for Gold(I)-Catalysis: From Inactive to ppm-level Catalysis,化学。Sci。2021.，12,4329 - 4337
- C. Schwarz, J. Handelmann, D. M. Baier, A. Ouissa,V. H. Gessner, Mono- and diylide-substituted phosphines (YPhos): impact of the ligand properties on the catalytic activity in gold(I)-catalysed hydroaminations,Catal. Sci. Technol.2019年，9, 6808-6815
- Thorsten Scherpf，Christopher Schwarz，Lennart T.Scharf，Jana-Alina Zur，Andreas Helbig和Viktoria H. Gessner，ylide官能化磷酸酯：强大的供体配体用于均匀催化，angew。化学。国际机关。艾德。2018年,57, 12859-12864.
Welcome to eureka moments
In conversation with YPhos ligand pioneer, Viktoria Gessner