A spoonful of sugar makes the catalytic activity go down! [Dalton Trans.]

I’m delighted to finally publish this work, the first of my research carried out during my Marie Curie Fellowship in University of Bern to come out. A lot of hard work by Erasmus student Pauline went into gathering data behind this manuscript where we asked the question – what impact would incorporating carbohydrates into the structure of a Ruthenium(II)-triazolylidene complex have on its ability to convert a ketone to an alcohol via transfer hydrogenation catalysis.

There were challenges in isolating the desired compound, so it had to be generated in situ, but we were able to assess the activity, and the results were interesting, and can be found in detail here in Dalton Transactions.

To summarise the conclusions: The carbohydrate functionality does impact catalytic activity (transfer hydrogenation of ketones). In complexes with the glucose directly triazolylidene-bound,  turnover rates were substantially higher when compared to more remote carbohydrate functionalisation (i.e. with an ethylene spacer). Both new complexes, however, have reduced activity compared to  unfunctionalised carbene complexes. Insight was also gained into the nature of the catalytic cycle through a substrate scope analysis.

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Seasons of Lab

Seasons of Lab

 ♫ “Five hundred, twenty-five thousand, six hundred reactions…”

That song from the musical Rent is in my head as I write this post on seasons. It’s a catchy one that brings back memories of my misspent youth hanging out with people who would sing showtunes at the drop of a hat in perfect four-part harmony!

One of the things I love about working in a chemistry lab and constantly making new compounds as part of my research is the beautiful accidental shapes and patterns molecules can assemble into, given enough time – and how our pattern-seeing brains can ascribe poetic meanings to these patterns based on what we want to see! Two recent examples from my own work caught my eye enough recently to pull out a camera and snap a shot. They tell a chronologically-consistent story of the changing seasons, as the colours of Bern’s horizon have changed from auburn to snowy white this last month, I’ve seen fallen leaves and swirls of snow in the bottom of round-bottomed flasks:

Autumn left behindWinter precipitate

Obviously crystals are some of the most beautiful formations that we can see in the lab, with their sparkle and sharp, defined edges: needles, plates, and more complex symmetries. As chemists, we love large ‘single crystals’ which can be subjected to X-ray diffraction experiments to generate the molecular structures which illustrate the pages of so many research articles these days. I had an old starting-material from much of my work in Trinity College Dublin (2,6-Bis(trimethylsilyl)ethynylpyridine, if you must know), which loved to crystallise. I believe I fished out a crystal of it from a reaction mixture once, hoping it would tell me something about a new exciting product, but alas no. Nonetheless, my colleague Dr Salvador Blasco solved this structure, which, despite not telling us anything new, was pleasingly symmetrical:

2,6-Bis(trimethylsilyl)ethynylpyridine

I often think with wonder about the deep insight of early chemists into the nature of matter that they could be so certain of chemical structures with a small range of tools like melting-points, taste, and a series of tests and probes; we have access to so many techniques nowadays that we take for granted that can show us, atom by atom, how a molecule fits together. So often, the early chemists of a century and more ago were right or close to it based on wisdom intuition and methodical analysis.

With major developments in materials science in recent decades, tools such as Scanning Electron Microscopy and Helium Ion Microscopy have allowed us to look closely at how the surfaces of substances are arranged on a slightly larger scale than single molecules, which can be vital to understanding them. More pertinent to the whimsical theme of of this post is just the fascination you feel when seeing that, on zooming all the way in, the flexible gel-like substance you have made looks like a plate of spaghetti, or a woven cloth. The picture below comes from my Dalton Transactions article, thanks to my collaborators Drs Kotova, Bell and Prof Boland, working at CRANN/AMBER in Trinity College Dublin:

Helium ion miscroscopy of a metallogel

There is beauty and fascination everywhere. It’s just a matter of how far you need to zoom in to see it!

Swiss Chemical Society Fall Meeting

A large contingent from the Albrecht research group in Bern made our way down to Lausanne today for the Swiss Chemical Society’s annual Fall Meeting at EPFL. As always, it was a massive meeting, underscoring the impressive amount of chemistry research that goes on in small-but-mighty Switzerland.

The introductory speaker, Prof Emsley, highlighted some unique aspects of Swiss research, including the strong industrial presence in the country (indicated by the generous sponsorship of every session by pharmaceutical and instrumentation companies), as well as the rich international complexion of the researchers who work at the Swiss Universities and companies. More than a quarter of all researchers are non-nationals – and that is a real strength, allowing for diverse workers and ideas to come together from all over Europe and the world. Mobility and openness, in principle, allow the best people to find the best partners for their research and push forward important developments in science.

One of my colleagues presented his recent results (Angewandte Chemie), while seven of us presented posters over the extended lunchtime session. Lots of interesting conversations were had with researchers at other universities, as well as industrial chemists; in Switzerland industrial chemists are well integrated into the professional society (the SCS), which I think is beneficial to all of us, for focussing our targets and sharing the latest advances. Indeed, in addition to leading academics like Prof Karsten Meyer, we also saw presentations from the likes of Syngenta.

We got to socialise a little and explore the EPFL campus after the talks, and, in the Rolex Building, I was lucky enough to run into old friend Marie Curie! I had a colleague snap this photo of me and the other Marie Sklowdowska-Curie Fellow in the Albrecht group with our mentor! She’s everywhere!

Marie Curie and her fellows

 

Chemistry in the Rising Sun – ICCC in Sendai

Pictures of me presenting at ICCC in SendaiI am just after returning from the 43 (and largest ever) International Conference of  coordintion Chemistry in Sendai, Japan. This year’s ICCC had an awful lot to offer, with 2,500 of us in the Sendai International Centre, and spread over up to twenty parallel session at times, there is clearly a lot happening in inorganic and coordination at the moment. Some highlights included fascinating molecular machines (with an inspiring closing address from 2016 Nobel laureate Jean-Pierre Sauvage), catalytic approaches to the challenges presented by the need to find new fuel sources for a changing world, new pincer and NHC ligands, luminescent diagnostic probes and therapeutic agents and much much more.

Me speaking from the podium in the Exhibition Hall on Thursday morning

I was privileged to get the chance to present my work in Session 38 “Organometallic complexes for synthesis and polymerisation”, to a room full of my peers and leaders in the field, including people I had interacted with during the week and who came along to see what it is I am up to in my current work! My presentation on the catalytic activity of carbohydrate-functionalised N-heterocyclic carbene complexes went very well and there were even a few useful questions that prompted a bit of discussion afterwards.

After Thursday morning, I could relax a bit more and just enjoy attending the sessions without worrying about perfecting my talk! Luckily that afternoon had also been set aside on the programme for sight-seeing, so I wandered around the site of Sendai Castle and the adjacent shrine with a few other chemists. I also got to sample the regional delicacy of beef tongue and make my own chopsticks from scratch. A nice mix of learning, culture and networking.

 

I really enjoyed catching up with old colleagues from Europe and the UK and meeting new people from both hemispheres to share ideas with (as well as a fateful trip to karaoke after the conference banquet wrapped up earlier than necessary) as well as the engaging discussions had at the poster sessions. I’m also getting better at asking questions after lectures, as my confidence in the field grows with experience!

Looking forward to the next one in Rimini!

Thanks, of course, to my Marie Skłodowska Curie Fellowship (GLYCONHC) and the European Commission for funding the work which I presented

I’m calling this photo a Bunsen Byrner

Recently I was lucky enough to get an invite to the 11th CaRLa Catalysis Winter School in Heidelberg, and it was an eye-opening and engaging week, meeting with some of the rising talents within the fields of homogenous catalysis (among others) and hearing from speakers like Mats Tilset (check out his recent article on trans-mutation of gold – a pun I really approve of) and Ilan Marek about their contributions to the field. In particular, I enjoyed having a week to spend time discussing posters with the other attendees; normally this is the most rushed part of any conference, as you try to simultaneously stand by your own poster and see as many others as possible. The Winter School invited flash presentations on all the posters, and gave ample time and coffee over which to really get into the details!

I was able to present my on-going research from my Marie Curie Individual Fellowship (GLYCONHC, MSCA-IF 749549), where I investigate the impact of including carbohydrates in the structure of metal-NHC catalysts. The work is progressing well, and I think I benefited from being able to discuss hurdles in the project with catalysis experts and my peers during the week.

CaRLa (The Catalysis Reasearch Laboratory) is an institute at University of Heidelberg, supported by BASF, a giant of the chemical industry. As a result, the research they undertake is very aligned to real economic and market challenges. We were given a tour of the massive site at Ludwigshafen on the river Rhine, and the scale of production in just the one plant we visited was staggering – round-bottom flasks just can’t compete with building-sized reactors!

One interesting historical note about Heidelberg is that it is where Robert Bunsen did much of his pioneering work in 19th century chemistry and – famously – gifting us with the most widely known (and least widely-used nowadays) apparatus of the chemistry lab. I couldn’t walk past his statue without getting a punny selfie- the “Bunsen Byrner”!