Designer molecule

Designer molecule video transcript

Facilitator: Dr Andrew McDonagh, I know that you work with the School of Chemistry and Forensic Science at UTS, and I understand that you work in the area of synthetic chemistry, but I'm not even going to begin to pronounce the specific area of research that you're working on at the moment; what is it?

Interviewee: Okay, we're looking at molecules called ruthenium phthalocyanine complexes. It seems like a bit of a mouthful, but when you unpack it, it's pretty straightforward. Ruthenium is a metal. You can find that in the periodic table. Phthalocyanines are a type of molecule that are closely related to the porphryns, and you find porphryns in things like chlorophyll, so in leaves of trees and plants; in haem, so in red blood cells - they're the colour givers to the red blood cells. So these molecules are closely related to that. The reason we're looking at them is they're very strong dyes. They absorb a lot of light and have a very strong colour.

Facilitator: Specifically what are you hoping to find?

Interviewee: What we're doing is we're using these molecules to construct structures on surfaces that we can then probe. I guess the ultimate goal is that we'd like to isolate one of these molecules all on its own and probe its electronic properties.

Facilitator: Why would you want to be able to do that?

Interviewee: The idea is that we want to probe a molecule all on its own. That is, a well-defined and single molecule and look at its electronic properties. Now, we can look at molecules in large groups; we can look at many millions or billions of molecules, but to get one all on its own and in a well-defined structure is quite a challenge. But it should reveal something pretty fundamental about the nature of those molecules.

Facilitator: What do you mean by that?

Interviewee: How do the electronic properties of that molecule operate? So, at what point do the energy levels in that molecule line up with the energy levels of the electrodes that you've sandwiched it between, and how does it behave as a single entity compared to as a group.

Facilitator: Can you explain how potentially one day this might have real life applications?

Interviewee: Well, my honest answer is I don't want to predict where this might be applied in the future. This sort of science is very fundamental, so it uncovers very basic properties about molecular structures. So it may be that someday in the future someone will take these particular properties and come up with a new device, a new type of device that operates in a completely different way that we understand devices operate today.

Facilitator: Would you compare it to research that was once done in the past?

Interviewee: I guess a long time ago people were investigating how transistors worked. I'm sure that they never envisaged the absolute minute componentry that goes into the integrated circuits, and the computer chips that we take for granted today. So perhaps this sort of work will find its way into some analogue of that in the future.

Facilitator: How do you do this research?

Interviewee: The first thing that we do is we sit down and we design our molecule. We work out what parts our molecule has, whether it's going to be of a particular shape or geometry. We then work out the chemistry that we need to do to put that together. The next step is actually going to the lab and doing it. At that point, we design our synthesis; we collect all our starting materials and we put them together in a way that we're pretty sure that will give us the compound that we're after.

Once we've put together our molecule, we need to know exactly what we've done. We need to know that we've made what we said we would with atomic precision. So, the way that we do that is usually the first thing we do is we look at the nuclear magnetic resonance spectrum of our compound, and that will tell us the environment of the hydrogen atoms, the carbon atoms and, if we have any other atoms in there like phosphorus as well, that will tell us the environment they're in. Using some reasonably straightforward rules, we can then work out whether we've connected all our atoms together in the way that we wanted to.

Facilitator: All that equipment sounds pretty high tech. Do you have to be a genius to be working at this level?

Interviewee: Well, the equipment itself, yes, is quite high tech, and the synthetic techniques are something that can be learnt, but no, you don't have to be a genius to do all of this. This is accessible to anyone pretty much from the first-year university level onwards. We regularly have people that come in in their holidays and do some research, and they have access to all this equipment. They make new molecules and they get to characterise them themselves.

Facilitator: So what's your end game?

Interviewee: In science there is no ultimate end game. As soon as you come up with a bunch of answers to some questions that you've asked, that will throw up a whole bunch of new questions, and so it keeps going.

Facilitator: Well, Dr Andrew McDonagh, it sounds like you do have a lot of work ahead of you; good luck, and thank you for your time.

Interviewee: All right, thank you.

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