Seminars

Find out about upcoming seminars in the Department of Chemistry.

Dainton Building
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February - May 2021

All departmental seminars are held via Blackboard Collaborate, unless stated otherwise. Departmental Seminars will all be held at 1pm on Wednesdays. Please always check the time as it might change for some speakers.

February

 


Departmental seminar: Exploiting Physical Organic Principle in Selective Reaction Design

10 February 13:00 - CANCELLED (TO BE RESCHEDULED)
Blackboard Collaborate

Speaker: Prof. Dr. R. Gilmour
(Westfälische Wilhelms-Universität Münster)

Contact: Prof Anthony Meijer

Abstract

Controlling molecular space in 2- and 3-dimensions is a challenge that continues to be intensively pursued. In this lecture, contra-thermodynamic isomerisation via energy transfer catalysis will be discussed together with our latest contributions to the field of stereoelectronic conformational control. Molecular design strategies that profit from the intrinsic stereoelectronic and electrostatic effects of fluorinated organic molecules have mainly been restricted to bio-organic chemistry. Indeed, many fluorine conformational effects remain academic curiosities with no immediate application. However, the renaissance of organocatalysis offers the possibility to exploit many of these well-described phenomena for molecular preorganisation.


Departmental seminar: Targeting of Cell Permeable Metal Complexes Luminophores for Imaging and Therapy.

17 February 13:00
Blackboard Collaborate

Speaker: Dr. Tia E. Keyes
(Dublin City University)

Contact: Prof Jim Thomas

Abstract

Transition metal luminophores are emerging as important tools for intracellular imaging and sensing.   Their putative suitability for such applications had long been recognised but poor membrane permeability and cytotoxicity were significant barriers that impeded early progress. In recent years, numerous effective routes to overcoming these issues have been reported, inspired in part by advances and insights from the pharmaceutical and drug delivery domains.  In particular, the conjugation of biomolecules and other less natural synthetic species, from a repertoire of functional motifs have been applied .  They grant membrane permeability, cellular targeting and reduce cytotoxicity to transition metal complexes, and offer valuable avenues to circumvent problems leading to promising candidates for application in bioimaging, sensing and diagnostics.

In this contribution I will discuss our efforts to drive ruthenium (II) and Os(II)  polypyridyl luminophores across the cell membrane and in particular to drive them selectively to the repositories of DNA, the mitochondria and nucleus, within the living cell.  We demonstrate that judicious combination of cell penetrating or signal peptide and metal complex can enable precision-targeting to DNA with high selectivity within these organelles within live cells and indeed can be used to drive conjugates deeply into tumor spheroids opening opportunities for imaging and therapy.

I will also discuss some of the limitations that we have  that there are limitations to the effectiveness of these approaches which appear to depend on the lipophilicity of the metal centre and I discuss also, other non-biological appendages that can reliably ensure cell permeability.


Departmental Seminar: Transfer-dominated Branching Radical Telomerisation - novel uses for old chemistries

24 February 13:00
Blackboard Collaborate

Speaker: Dr Steve Rannard
(University of Liverpool)

Contact: Dr Seb Spain

Abstract

Branched polymers have been of academic and industrial interest for decades and their synthesis may be achieved by various strategies. Step-growth polymerisation and chain-growth mechanisms are both reported in the literature and industry has utilised both. We recently employed telomerisation chemistry, that is typically used to make very small molecules, in the formation of very high molecular weight branched polymers. We have named this approach TBRT and it utilises common free radical chain-growth mechanisms but generates step-growth backbone polymers. The talk will describe the background and the approach that we have developed and the licensing of this new polymer synthesis technique to Scott Bader - leading to the formation of Polymer Mimetics Ltd.

March

Departmental Seminar: The Role of Excimers in Singlet Fission

3 March, 10am
Blackboard Collaborate

Speaker: Tim Schmidt
(University of New South Wales)

Contact: Prof Anthony Meijer

Abstract

There are many applications that demand that the properties of light be controlled by molecular excitons. This includes upconversion applications, where shorter wavelengths are generated from longer wavelengths, and multiple exciton generation and photon multiplication, where a high energy photon is split into smaller energy packets. Over the past decade, we have applied triplet-triplet annihilation upconversion to photovoltaics. Recently, we achieved photochemical upconversion from beyond the silicon bandgap for the first time.

Singlet fission is a process where a photon-generated singlet state splits into two spin-correlated triplets. In solar cells it is hoped that this will give rise to two excitons per absorbed photon above a certain energy, increasing the efficiency limit to nearly 46%. Here I will discuss the role of the excimer state in singlet fission.

Departmental Seminar: Carbon: From Nanoscience to More-than-Moore Technologies  

10 March 13:00
Blackboard Collaborate

Speaker: Dr. Suprem Das
(University of Kansas)

Contact: Dr Natalia Martsinovich

Abstract

Carbon has been revolutionizing the field of nanoscience and nanotechnology since past few decades, with graphene as its latest allotrope that was discovered in year 2004. Graphene is truly two-dimensional atomic thin material that not only transformed basic understanding of solids, but it has inspired to the emergence of an entire family of materials, called 2D Materials. With more than a decade and half of research on its fundamental research, worldwide efforts have been gearing up for unlocking graphene’s potential for unique applications. In this talk, I will summarize our efforts for graphene’s scalable applications from transparent conductors to electrochemical sensors. I will conclude with a preliminary discussion of our ongoing collaboration with University of Sheffield for a development of graphene-based soil phosphate sensors, an ambitious move towards graphene’s potential for precision agriculture.  


Departmental Seminar: Artificial synthesis of amorphous framework materials designed for energy applications

17 March 13:00
Blackboard Collaborate

Speaker: Dr Abbie Trewin
(University of Lancaster)

Contact: Dr Rob Dawson

Abstract

We show computational methodology that enables us to artificially synthesise amorphous framework materials in-silico, using the real-world conditions and following the catalytic mechanisms, so that we can design materials for targeted applications.

Amorphous porous framework materials, including hyper-crosslinked polymers (HCPs), have been suggested as ideal materials for use in energy storage, particularly as the anode material in lithium ion batteries (LIBs). However, it is very challenging to rationalise their atomic structure and hence rational design and full understanding of their properties is not currently possible.

An example of a HCP for an energy application is organically synthesised porous carbon (OSPC-1), which was specifically designed using the structural building units, ethynyl methane to form a 3-D connected carbon amorphous network. Three highlights brought this to the attention of a wide audience: (i) an unexpected electron conductivity, (ii) an ability to be charged with more than twice the amount of lithium as compared to the graphite electrodes in state-of-the-art lithium ion batteries, and (iii) an ability to be charged at a high rate without any signs of detrimental lithium plating or dendrites that can cause explosions of devices. This opens up the potential to discover other amorphous framework materials for use as anodes with exceptional storage, safety, and charging properties.

 Rational design approaches have been used to great effect in the discovery of crystalline materials. However, amorphous framework materials are kinetic products and we therefore cannot use the same approaches. Here we will show that the use of our in-house developed Ambuild can be used to aid the design of amorphous framework materials through high through put material prediction and design.


Departmental Seminar: Designing synthetic strategies and in situ monitoring for next generation battery materials

24 March 13:00
Blackboard Collaborate

Speaker: Prof Serena Corr
(University of Sheffield)

Contact: Prof Steve Armes

Abstract

All solid-state batteries present highly promising opportunities for safer energy storage. High ionic conducting solid electrolytes may overcome some of the limitations of organic polymer electrolytes, where safety concerns limit the electrochemical stability window, to provide a way to increase energy densities in a safe manner. However, resistance to ion mobility across the solid-solid electrode-electrolyte interface remains a bottle-neck to be overcome in realising this technology. The synthetic approach employed can potentially influence conductivities (and hence battery performance) exhibited by solid electrolytes and this talk will detail our efforts to maximise these properties through developments in our synthetic approaches.

Recent synthetic results on systems such as the NASICONs, garnets and perovskites where electrodes and electrolytes with similar crystal structures are applied, will be discussed. Comprehensive characterisation across multiple length scales of these systems will be presented, as well as recently developed in situ muon spin relaxation measurements interrogating lithium-ion diffusion will be shown. These results will showcase how careful synthetic design can enable performance and a comprehensive analysis provides greater insight into materials properties.

April

Departmental Seminar: Ultrafast spin and charge dynamics in molecular magnets

21 April 13:00
Blackboard Collaborate

Speaker: Dr Olof Johanssen
(University of Edinburgh)

Contact: Prof Julia Weinstein

Abstract

During the last 20 years, ultrafast transient absorption measurements of transition metal complexes have altered the understanding of how fast the spin-state of a molecule can change in the excited state. Notably, Fe(II) complexes can be switched from low-spin S = 0 to high-spin S = 2 in in less than 200 fs after absorbing only one photon [1–3], and similar processes have been observed in Cr(acac)3 [4,5]. We have studied a range of large transition metal complexes with exchange-coupled electrons, ranging from single-molecule magnets to magnetic coordination polymers, to explore ultrafast spin dynamics in molecules with several magnetic centres. We report the first ultrafast magneto-optical (MO) study of a molecule-based magnet  [6]. Thin films of the V-Cr Prussian blue analogue were studied and the MO measurements could detect a change in the super-exchange interaction taking place as a result of a spin flip occurring via intersystem crossing in less than 250 fs after the absorption of a pump photon. We have also carried out measurements on a tri-nuclear Mn(III)-based single-molecule magnet, whose magnetic anisotropy is closely related to the Jahn-Teller (JT) distortion. Ultrafast transient absorption spectroscopy in solution reveals oscillations superimposed on the decay traces with corresponding energies around 200 cm−1, coinciding with a vibrational mode along the JT axis. The oscillations arise due to a wave packet forming as the molecule adjust to the new JT geometry in the excited state [7]. The results open up new molecular-design challenges to control the wavepacket motion in the excited state of polynuclear transition-metal complexes.


Departmental Seminar: Learning the rules (or guidelines) of making molecular materials

24 April 13:00
Blackboard Collaborate

 

Speaker: Dr Anna Slater
(University of Liverpool)

Contact: Dr Jona Foster

Abstract

Building bespoke nanoscale molecular objects—e.g. organic cages, components for molecular machines, or macrocyclic host compounds—is challenging, but worth it if we ever want to approach the function, selectivity, and control seen in natural systems such as enzymes. This talk will focus on three approaches to control the formation of nanoscale molecular objects and molecular materials: 1) tuning the building blocks; 2) varying the interaction strength between building blocks, and 3) controlling the process by which they are made. 

I will illustrate these three approaches with our work on low-symmetry porous organic cages (POCs), supramolecular nanotubes formed via chiral recognition of POCs, and the use of flow synthesis for cages and a macrocyclic molecular hinge, exploiting the enhanced control and wider process windows of working in flow. How things are made is just as important as what they are made from: by combining these three approaches I will set out our strategy for the tunable formation of discrete nanoscale molecular objects.

May

Departmental Seminar: Making Difficult-to-Make Molecules: Photochemistry as an Enabling Tool

5 May 13:00
Blackboard Collaborate

Speaker: Dr Susannah Coote
(University of Lancaster)

Contact: Dr Ben Partridge

Abstract

Converting simple starting materials into complex products using only a light source (synthetic photochemistry) is especially attractive to organic chemists, particularly from the point of view of green chemistry: waste is minimized, and light is readily available. In addition, photochemical routes often allow efficient access to complex frameworks (particularly to strained molecules and intermediates) that cannot be generated using ground-state chemistry. In this seminar, our recent work on the synthesis and applications of bicyclic 1,2-diazetidines 2 will be presented. Bicycles 2 can be obtained in high yields from 1,2-dihydropyridazines 1 simply upon irradiation at 350 nm, and are versatile synthetic intermediates that can be converted into a variety of different derivatives, including substituted 1,2-diazetidines, cyclobutanes, cyclobutenes and dienes. In addition, related work on similar systems will be discussed, including ongoing unpublished work.


Departmental Seminar: TBA

12 May 13:00
Blackboard Collaborate

Speaker: Dr Susan Quinn
(University of Dublin)

Contact: Prof Julia Weinstein

Abstract
TBA

 


 

Summer 2021

June

Departmental Seminar: Theory-guided Design of Organic/Carbon-based Semiconductors for Energy Conversion

Tuesday 15 June 14:00 
Blackboard Collaborate

Speaker: Dr. Xue Yong 
(University of Sheffield)

Contact: Prof Anthony Meijer

Abstract

The overconsumption of natural resources, global anxiety of energy crisis, environmental pollution, and global warming have spurred strong interest in finding alternative and environmentally friendly energy technologies such as reusing the waste (thermoelectric devices), utilizing solar energy or renewable hydrogen energy. However, the efficiency of these technologies relies largely on high-performance and advanced multifunctional materials that requires rational material design. Organic/carbon-based semiconducting materials, e.g., polymers, graphene, Carbon Dots, have seen great potential in these technologies due to their unique properties such as light weight, high flexibility, solution processability, and low cost. However, the key challenge for the rational design of organic/carbon-based semiconducting materials is to understand and fine tune their geometry, physical and electronic properties, and corelate to the macroscopic properties for target applications. In this talk, I will first present some theoretical studies on the structure-property relationships of selected organic/carbon-based semiconductors for energy conversion. Then, I will discuss my future research on Carbon Dots, which is an emerging type of carbon-based conducting nanomaterial with potential optical and energy conversion applications. 


Departmental Seminar: TBA

 June 13:00 
Blackboard Collaborate

Speaker: TBA


Contact: Prof Anthony Meijer

Abstract

TBA

July

Departmental Seminar: How ultraviolet photoprotection works and what to do when it goes wrong

13 July 2020 14:00
Blackboard Collaborate

Speaker: Dr. Michael Horbury
(University of Leeds)

Contact: Prof Anthony Meijer

Abstract
As the number of cases of skin cancer has been on the rise worldwide, the importance of protecting the skin against the deleterious effects of ultraviolet radiation has become increasingly pertinent. This is further compounded by the controversy around commonly used sunscreening agents and the ever-increasing uncertainty in the climate. In this talk I present a vision to help reduce and mitigate the detrimental impact of ultraviolet radiation on the human skin, which can be achieved through three parallel research objectives. First, climate modelling can be improved by building a more detailed understanding of atmospheric chemistry, via the use of terahertz frequency resolved spectroscopy. Second, new and superior sunscreening agents can be developed through the understanding of the photochemistry of natural and synthetic photoprotective molecules, to guide the creation of new sunscreening agents. Third, cancer treatments can be improved by using photoactive metal-complexes to provide targeted activation to significantly reduce side effects and, by developing an understanding of their photochemistry, targeted modifications can be used to improve their effectiveness. Ultimately, through this multipronged approach the rise in incidences of skin cancer can be halted and reversed.

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