Chemistry seminars
Find out about all of the upcoming seminars in the Department of Chemistry.
Autumn-Winter 2024-25
Departmental Seminars are generally held on Wednesdays. Please always check the time as it might change for some speakers.
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October
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Departmental Seminar: The Changing Shape of DNA in Genes
2 October 12:00 DB-LT01
Speakers: Prof Zoe Waller
(University College London)
Contact: Prof Jim ThomasAbstract
DNA is not always a double helix. Cytosine-rich DNA sequences are able to form i-motifs, four-stranded structures comprised of parallel-stranded DNA duplexes connected in an anti-parallel orientation by intercalated, cytosine–cytosine base pairs. i-Motifs are stabilised by acidic conditions, which promote C-C base pairing via hemi-protonation of the N3; folding is rapid and this property has been utilised in many different nanotechnological applications. It is often assumed that i-motif formation is dependent on low pH, but there have always been examples where they are still present under neutral conditions. i-Motif can form at neutral pH depending on the types of sequence, cations and the presence of ligands. i-Motif structures have been shown to form in cells and stabilisation of i-motif structures has been found to destabilise G-quadruplex DNA structures in cells, disrupt the action of the enzyme telomerase, inhibit DNA polymerase and enhance gene expression.
Here I describe recent work from our group towards understanding the relationship between GC-rich sequences in the human genome, the different structures they can form and their different biological functions.
Departmental Seminar: Sustainable bio-sourced coatings for the food sector - preservation and sensing of food quality
9 October 12:00 DB-LT01
Speaker: Dr Chester Blackburn
(University of Sheffield)Contact: Prof Nick Turner
Abstract
The dairy industry in the UK is estimated to be worth around £8-9 Bn to the UK economy. However, at least a third of food production globally is estimated to be wasted, a driving force behind climate change. Dairy products are understood to retain quality and be fit for consumption past their “Best before” date, as the date is largely an indication of quality rather than safety; therefore, the consumer is encouraged to use sensory tests (smell, appearance etc.) to make a judgement on the quality of the food. However, as not all consumers are comfortable making this assessment, and given it is a subjective judgement, there is a significant amount of dairy produce food waste that otherwise could be consumed.
This talk will focus on an idea being proposed for a UKRI (FLF) Fellowship application. I will discuss my prior and current research experience. Proposing, the use of multi-functional sustainably sourced biopolymers and small molecules for incorporation into food packaging to function as both an anti-fouling layer and quality guide of dairy products, namely soft cheese and milk.
Departmental Seminar: 2D Framework Materials for Energy Applications and Molecular Separations
16 October 12:00 DB-LT-01
Speaker: Prof Andreas Schneeman
(Technische Universität Dresden)Contact: Dr Jona Foster
Abstract
Framework materials like metal-organic frameworks or covalent organic frameworks (COFs) are porous, crystalline materials constructed from molecular building blocks. In COFs, the building blocks are connected via covalent bonds, forming robust networks. If they are flat, highly symmetric molecules, two dimensional frameworks can be constructed, which are stacked in the third dimension by weak interactions for instance hydrogen bonds or π-π interactions. By functionalization of the framework backbone with aliphatic side chains the stacking is weakened and their surface properties drastically change, making them hydrophobic. This can be leveraged for instance in pyrene-based COFs, which can be exfoliated from organic solvents into nanosheets with average thicknesses below 1.5 nm, which were integrated into separator membranes for lithium-ion batteries. This concept was transferred to electrocatalytically active metalloporphyrin COFs and the inclusion of side chains improved their stability in alkaline media, increasing their stability during the oxygen evolution reaction and lowering the overpotential compared to non-functionalized analogues. Furthermore, the stacking-offset between adjacent layers in metalloporphyrin COFs can be adjusted by the type of attached side chain, as well as the degree of metalation.
Stacking-offsets can also be leveraged for molecular separations. Introduction of alkyne bridges into a pyrene-based 2D COF induced a shift between neighbouring layers, which created electron-rich pockets. These pockets are used for static bromine adsorption from the gas phase, as well as for the selective uptake of Br 2 from mixed Br 2 /I 2 solutions. Hydrophobization of the framework backbone can not only be achieved by installation of aliphatic side chains, but also by substituting aromatic linkers with saturated molecules. With this strategy, a cyclohexane-bridged COF was prepared, which featured an increased affinity towards the adsorption of saturated hydrocarbons, showing high adsorption selectivity towards ethane over ethylene.
Departmental Seminar: TBA
23 October, 12:00 DB-LT01
Speaker: Dr Alex Cresswell
(University of Bath)Contact: Dr Ben Partridge
Abstract
Alex's research combines photochemistry with organic synthesis. More specifically has explored combining visible light photocatalysis and Hydrogen Atom Transfer catalysis to generate unprotected alpha-amino radicals from primary amines. These nucleophilic radicals can then be trapped with electrophiles such as alkenes to generate complex C-tertiary amine products. His group has applied this approach to synthesise a range of interesting, medicinal-chemistry relevant chemicals.
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November
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Departmental Seminar: Developing Automated Experimentation for Delivering the next generation of Polymer Materials
6 November 12:00 DB-LT01
Speaker: Prof Nick Warren
(University of Sheffield)
Contact: Prof Steve ArmesAbstract
Applying enabling technologies such as automation and artificial intelligence (AI) in materials science is one of the only options when it comes to meeting the need for the next-generation materials required to sustain society. Despite considerable uptake of emerging technologies in small-molecule chemical synthesis, it is still yet to become commonplace within polymer science and there is little sign of a significant shift away from traditional ‘flask based’ techniques. By making advances in reactor design, online monitoring and automation our research explores technologies which have the potential to accelerate discovery and development of chemical products including but not limited to polymers. This talk outlines our progress to date, which focusses on the development and implementation of automated reactors equipped with online monitoring and computational intelligence. It is demonstrated that these platforms are capable of autonomously exploring reaction parameter space with minimal human interaction. This includes the ability to conduct automated kinetic screens or for AI-driven multi-objective self-optimisation of polymerization conditions. As a result, reaction optima and trade-offs inherent with the process can be autonomously identified. It is demonstrated that optimum reagents and conditions for the polymerisation of several monomers can be determined with no human interaction and minimal prior knowledge of the chemistry. By expanding reactor capability and augmentation of chemical models, we show that it is possible to further reduce the need for physical experimentation, which has significant implications with respect to efficiency and sustainability.
Departmental Seminar: Nanoscale dynamics and organisation at solid-liquid interfaces: from single molecules to correlative group effects
13 November 12:00 ADB-LT02
Speaker: Prof Kislon Voïtchovsky
Contact: Prof Nadav AmdurskyAbstract
Liquid molecules behave differently at the surface of immersed solids compared to bulk liquid. This ‘interfacial liquid’ can control nanoscale processes, from molecular self-assembly to local electrostatics, molecular transfer and lubrication. In soft matter and in biosystems, the effect is further enhanced by the interfacial liquid’s ability tune the structure and properties of the solid, from the shaping of dissolved polymer molecules to the mechanics of living cells.
Using bespoke experimental approaches based atomic force microscopy, it is possible to map the equilibrium organisation and local diffusion dynamics at solid-liquid interfaces with nanoscale precision. The results, complemented by computer simulations, show an interplay between local molecular organisation and the emergence of mesoscale phenomena over hundreds of nanometres though group effect. In bio-membranes, for example, water-stabilised ionic condensates can remain in place for tens of seconds, dramatically altering the local electrostatics and mechanical properties with consequences for the membrane shape. We also track the mobility of interfacial water and of the molecules within fluid membranes and show how correlated motion can control self-assembly.
Departmental Seminar: A journey through responsive systems that interact with light – from DNA to Dyes
20 November 12:00 DB-LT01
Speaker: Dr Denis Hartman
(University of York)Contact: Dr David Williams
Abstract
Light-matter interactions are crucial in the development of new technologies and currently find use in all areas of chemistry, from light-responsive systems in biology to modern optoelectronic devices. One area that this finds use in is in the remote control of biological function. I have developed photoresponsive systems that are able to control transcription and translation with light through modification of DNA. Due to the orthogonality of the photocages, simple logic gates could also be constructed and this was implemented in synthetic cells. Another area of interest is in chiroptical materials, which can find use as sensors, emitters and spintronic devices. Here, I have developed chiral switching supramolecular architectures based on perylene diimide dyes. These systems allowed for switching of chiroptical properties with external inputs, such as solvent or guest species, as well as state of matter.
In the talk I will be embarking on a journey through several ways that we can harness light, show some subtleties in the chemistry that governs this, and display the exciting potential that arises from the utilisation of such systems in a variety of contexts.
Departmental Seminar: Ligand Design in Molecular Materials Chemistry
27 November 12:00 DB-LT01
Speaker: Dr David Herbert
(University of Manitoba)
Contact: Prof Julia WeinsteinAbstract
Abstract: The C=N bond is a critical structural piece of many N-donor ligand scaffolds and is central to the properties and reactivity of a number of important coordination complexes - for example, promoting charge transfer character in complexes of bipyridines (e.g., [Ru(bpy) 3 ] 2+) or the "redox non-innocence” of alpha-diimine complexes. Benzannulation can extend the conjugated C=N containing π-system of pyridine to quinoline (2,3-benzopyridine) to acridine (2,3-benzoquinoline), stabilizing the lowest unoccupied molecular orbital (LUMO) of the molecule and boosting electron-accepting properties, but the positioning of the benzannulation matters. For example, phenanthridine (3,4-benzoquinoline), an asymmetric isomer of acridine, bears a similarly electronically accessible extended π-system but more chemically isolated imine-like C=N moiety. In this presentation, the impact of such site-selective π-extension on the chemistry and properties of phenanthridine as a molecule and ligand will be discussed.
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December
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Departmental Seminar: Electrophilic borylation and alumination for the functionalisation of sp2 and sp3 C-H bonds
4 December 12:00 DB-LT01
Speaker: Prof Michael Ingleson
(University of Edinburgh)
Contact: Dr Rob DawsonAbstract
C-H borylation provides efficient access to organoboranes that are ubiquitous synthetic intermediates (e.g. in Suzuki-Miyaura couplings and beyond) and are also increasingly important functional molecules in their own right. Examples of the latter include boron-doped polycyclic-aromatic hydrocarbons as emissive materials and organoborane based bioactives (including for tackling antibiotic resistance – e.g., Xeruborbactam). Our group has an ongoing interest in developing inter- and intra-molecular C-H borylation reactions using boron Lewis acids in what is a Boron analogue of the Friedel-Crafts reaction. This can use simple boranes, e.g., BCl3 and BBr3, or for more challenging conversions bespoke boron cations. This talk will cover a selection from our recent work on using boron electrophiles in directed C-H borylation, specifically in O-directed borylation e.g., to make useful intermediates for accessing bioactives (e.g. A) and in borylation directed borylation for functionalising sp2 C-H (e.g. to form B) and sp3 C-H (e.g. to form C) bonds. The latter involves an unusual sp3 C-H alumination.
Departmental Seminar: TBA
11 December 12:00 DB-LT01
Speaker: Dr Geraint Morgan
(Open University)
Contact: Prof Nick TurnerAbstract
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Departmental Seminar: Single-Protein Electronics: from Molecular to BioMolecular Electronic
18 December 12:00 DB-LT01
Speaker: Prof Ismael Diez Perez
Contact: Prof Nadav AmdurskyAbstract
In this seminar, I will present our latest efforts on understanding and control charge transport in a single-protein junction, with an emphasis on how to harness enzymatic activity electrically in an individual enzyme. Our approach relies on trapping individual redox proteins in an electrochemically controlled tunneling junction to characterize their main electrical signatures. The method can capture very fine details of the charge transport mechanisms across proteins in an aqueous environment.
I will first introduce the methodology with a couple of examples of electrochemically controlled single-molecule wires with synthetic backbones, then introduce our studies on a benchmark redox protein model such as a bacterial blue Cu-Azurin. We will show first the main observed electrical signatures of these systems that make them particularly efficient in transporting charge. We then bioengineer the outer protein surface using point-site mutagenesis as a mean to get a more detailed picture of possible electron pathways through the protein backbone.
Finally, I will switch to our very recent charge transport studies on redox enzymes. Using the above electrochemically controlled single-protein methodologies, we demonstrate that when an individual redox enzyme is trapped on a nanoscale junction, a distinct telegraphic noise can be directly correlated to the enzymatic activity of the enzyme during the active bioelectrocatalytic conditions. The last study opens a new door for the fundamental studies of redox enzymatic catalysis and brings prospects to the high-resolution electrical detection of an enzymatic reactions.
Spring-Summer 2024-25
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January
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Departmental Seminar: TBA
29 January 12:00
TBCSpeaker:
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February
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Departmental Seminar: TBA
12 February 12:00
TBCSpeaker: Prof Robert Mokaya
(University of Sheffield)Contact: Dr Rob Dawson
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19 February 12:00
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26 February 12:00
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March
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Departmental Seminar: TBA
5 March 12:00
TBCSpeaker: Dr Chris Spicer
(University of York)Contact: Prof Nadav Amdursky
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12 March 12:00
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19 March 12:00
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26 March 12:00
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April
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Departmental Seminar: TBA
2 April 12:00
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Departmental Seminar: TBA
30 April 12:00
TBCSpeaker: Dr Michaela Matta
(King's College London)Contact: Prof Anthony Meijer
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May
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Departmental Seminar: TBA
7 May 12:00
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Departmental Seminar: TBA
21 May 12:00
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June
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Departmental Seminar: TBA
June 12:00
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