So we're looking at controlling motion on a molecular level. We want to be able to do that on command as well. So when we mean a command, we can apply some sort of external input that could be light, it could be changes with pH, it could be using some redox chemistry, and basically that acts as a switch so we can turn that molecular motion on and off.
The last twenty to thirty years there's been interest in what are now called, I guess, molecular machines, and this culminated in the recent award of a Nobel Prize in 2016to three chemists. And it's all about really trying to replicate what we see all around us in the macroscopic world. Can we build really really tiny machines on the nanoscale and will they perform the same functions. Now we're thinking about different types of molecular system that can be incorporated into a device, or can be termed as a molecular machine, and ball-bearing type molecules have been less explored so far. So this is where our research fits in. Our approach in this is to really expand the toolkit of examples of molecular machines and so the idea of having a metal as the ball-bearing, just one atom at the centre of the molecule which other parts of the molecule can spin around, that would be a ball-bearing but on the molecular scale. What we're doing in particular with our system is we're looking at controlling the rotary motion about the ball-bearing axis of a cobalt metallocene.
So metallocenes are sandwich complexes, and in the middle we've got our cobalt atom and then it's sandwiched by two aromatic rings. The switch that we're using in our case, our chemical input, is a change in pH. So we've designed our system so that at neutral pH we have nice, free rotation about that metallocene axis, and when we lower the pH we have then designed our system so that we increase it's interactions with itself, it starts to hinder the rotation about that metallocene axis. We can probe this rotation about the metallocene axis using NMR, and one of the ways we need to do this is cooling it down to lower temperatures, and that's where we can start to see the different conformations that our metallocene is taking. So what we did is we recorded several NMR experiments starting at twenty five degrees Celsius and we went down to minus thirty five degrees Celsius. Every ten degrees we would run another NMR experiment and we can overlay those spectra and start to really map out the shifts, and the peak broadening, the shifts, the splitting that we see by overlaying them.
With the help of Cecile and the NMR team here I was taught how to really tailor the conditions to fit our molecule perfectly, in what is really actually quite a complex molecule. So I work doing carbon dioxide reduction and it's obviously important in terms of global warming and climate change, and in terms of my research I can use electrochemistry to convert carbon dioxide back into useful products. The carbon dioxide is an important heat-trapping greenhouse gas and its accumulation in the atmosphere result in an increase of the global temperature.
Global climate change has already had observable effects on the environment. Worldwide it is recognized a recycling carbon dioxide to fuels another high added-value chemicals is a key element to a sustainable, low-carbon economy. CO2 recycling will playa vital role in worldwide efforts to limit global warming and will allow us to deliver one fifth of the emission reduction needed by 2050. So using electrochemistry we can turn carbon dioxide back into useful products, This is carbon oxide utilization. And we can turn into things like methanol, ethanol and formate. Things like methanol can be used as fuels, formate is a very important precursor in chemical industries, ethanol is also another type fuel. These products are obviously more useful than carbon dioxide which is very inert and we have to sequester and put underground if we don't want it contribute to global warming. So when I'm doing carbon dioxide reduction electrochemically, we have to do it in aqueous electrolyte because that's what provides the protons for the reduction reaction. We obviously have a very large water peak that we don't want to see so the NMR that we do suppresses that water signal peak without losing all the other little signal peaks around it that we want to see. When I'm doing my electrochemistry I change the electrolyte in order to get the best reaction conditions and this affects the NMR spectrum that we get. Bridget and Cecile from the NMR department helped me quite a lot in order to change the parameters of the pulse sequence so I can get the best quantification which is the end goal of doing this kind of NMR.
