Congratulations to Promeet Saha who passed his PhD viva this week! Promeet joined our group initially as a summer student, then for a final-year undergraduate project before starting his graduate studies in 2020. His thesis deals with overcrowded systems that exhibit ruptured aromaticity or undergo photocyclisations. Good luck to Promeet in his next step as a postdoctoral researcher with Rafal Klajn at the Institute of Science and Technology Austria.
Our latest paper is out in JACS, describing the use of high-pressure crystallography and high-pressure optical spectroscopy to investigate how packing influences the optoelectronic properties of organic chromophores.
Thanks to our excellent collaborators Prof Stephen Moggach (Univeristy of Western Australia) and Prof Anita Jones (University of Edinburgh).
Abstract: To develop luminescent molecular materials with predictable and stimuli-responsive emission, it is necessary to correlate changes in their geometries, packing structures, and noncovalent interactions with the associated changes in their optical properties. Here, we demonstrate that high-pressure single-crystal X-ray diffraction can be combined with high-pressure UV–visible absorption and fluorescence emission spectroscopies to elucidate how subtle changes in structure influence optical outputs. A piezochromic aggregation-induced emitter, sym-heptaphenylcycloheptatriene (Ph7C7H), displays bathochromic shifts in its absorption and emission spectra at high pressure. Parallel X-ray measurements identify the pressure-induced changes in specific phenyl–phenyl interactions responsible for the piezochromism. Pairs of phenyl rings from neighboring molecules approach the geometry of a stable benzene dimer, while conformational changes alter intramolecular phenyl–phenyl interactions correlated with a relaxed excited state. This tandem crystallographic and spectroscopic analysis provides insights into how subtle structural changes relate to the photophysical properties of Ph7C7H and could be applied to a library of similar compounds to provide general structure–property relationships in fluorescent organic molecules with rotor-like geometries.
Congratulations to final-year PhD student Yuzhen Wen who won the prize for best presentation in the Molecular Materials section of the annual Chem@York symposium! Yuzhen presented her work on dynamic barbaralane stereochemistry, AKA ‘ping-pong alkenes’.
Well done to PDRAs Dr Aisha Bismillah and Dr Rabia Ayub who won presentation and poster prizes at the Empowering Women in Organic Chemistry Europe Conference!
Congratulations to Burhan Hussein who recently completed his PhD viva! Burhan’s PhD was supported by the Soft Matter and Functional Interfaces CDT, as well as the Natural Sciences and Engineering Research Council of Canada (NSERC). His thesis on the ‘Control of Dynamic Supramolecular Systems’ was examined by Profs Jon Steed and Guillaume De Bo.
Since leaving the McGonigal Group, Burhan has retured to Canada as an NSERC Postdoctoral Fellow in the Lumb Group at McGill University where he is investigating silanes as cancer therapeutics.
Congratulations to Promeet Saha for winning a poster prize at York Chemistry’s Johnson Matthey poster competion held on 30 March. Promeet poster ‘Rupturing Aromaticity by Periphery Overcrowding’ was selected for one of the three prizes.
We have published a paper in Nature Chemistry describing the dynamic inversion of carbon-centred stereochemistry in fluxionally chiral carbon cages. Watch the video below for an animated summary.
We showed that with appropriate substitution patterns, the rapid and reversible Cope rearrangement of barbaralane carbon cages interchanges pairs of enantiomers. The sp3-C stereocentres in their structures are inverted.
Typically, inverting sp3-C stereocentres requires high-energy bond-breaking and bond-making steps through step-wise intermolecular reactions with external reagents. But the barbaralane stereochemistry is intrinsically dynamic. Our paper shows the consequences of this dynamic bonding: the cage adapts its stereochemistry in response to its environment (through covalently attached groups or associated ions); its rearrangements can be stopped, restarted, and slowed down; and it can pass on its dynamic stereochemical properties to chiral-at-metal ions through forming organometallic complexes.
The research was led by group members Aisha Bismillah, Toby Johnson, and Burhan Hussein. Congratulations to all the team!
Our investigation of the interplay between strain and aromatic stabilisation energy has been published in Nature Chemistry.
We use peripheral overcrowding to increment the strain energy around an aromatic cation ring (tropylium). Moderate overcrowding causes the tropylium to twist, but beyond a certain strain energy we found that the aromatic ring ruptures to produce a bicyclic ‘Dewar tropylium’ system. Surprisingly, ramping up the strain energy in this way doesn’t appear to diminsh the aromatic stabilisation energy. Instead, the strain and aromaticity can be balanced so the aromatic and nonaromatic isomers exist in rapid, thermal with one another.
The research was led by PhD student Promeet Saha and PDRA Dr Abhijit Mallick. Congratulations to the whole team!
The McGonigal Group travelled to Nottingham for the annual RSC Macrocyclic and Supramolecular Chemistry Meeting on 18-19 December. It was a bumper year with 272 delegates and a schedule packed with fantastic talks and posters! Congratulations to our postdoc Dr Aisha Bismillah who was one of the poster presenters selected for a prize - well done Aisha!
Congratulations to PhD student Rob Ives for being selected as a poster prie winner at the 8th Prague–Weizmann Summer School, Advances in Drug Discovery. The prize will enable Rob to attend the European Chemical Biology Symposium (ECBS) in Gothenburg next summer. Well done Rob!
This week the group travelled to Loughborough to attend the fantastic ECR MASC conference (the annual meetings of the RSC’s Macrocyclic and Supramolecular Cheimstry interest group aimed at Early Career Researchers). There were bucketloads of excellent talks and posters from the PhD students and postdocs who had come from supramolecular chemistry groups around the UK.
Congratulations to all of the prize winning contributions, including our very own Promeet Saha, who came away as one of the poster prize winners! Promeet presented a poster about his ‘ruptured aromaticity’ reserach - read more here.
This week we had the pleasure of returning for the first post-pandemic postgraduate symposium in Durham’s Chemistry Department. The whole department was out in force to reconnect over the excellent postgraduate and postdoctoral research talks and posters. Top marks to our PDRA Aisha for leading the event organisation and to those in the group who presented talks (Promeet, Yulong and Senthil) and posters (Yuzhen, Rob, Ash and Ho Chi). Extra congratulations to Promeet and Rob for their well-earned prizes :)
Congratulations to Jack Williamson who successfully defended his PhD thesis this week! Jack completed his PhD as part of the Soft Matter and Functional Interfaces CDT on the topic of the ‘Synthesis and Material Properties of Aromatic Cation-Centred Compounds‘. External examiner Dr Tom Chamberlain from the Univeristy of Leeds joined internatl examiner Dr Will Brittain for the viva exam. Jack has moved on to a position with Almac in peptide synthesis. Well done Jack!
Paul has been awarded the 2022 Harrison–Meldola Memorial Prize from the Royal Society of Chemistry! The award has been given ‘for innovative studies of dynamic processes in organic functional materials‘. As part of the prize, Paul will give a short lecture tour of UK univeristies organised by the RSC.
We have published an article titled ‘Extended Conjugation Attenuates the Quenching of Aggregation-Induced Emitters by Photocyclization Pathways‘. Click this link to read the paper in Angewandte Chemie.
Congratulations to former PhD student Andrew Turley who is the lead author alongside other team members from the McGonigal Group and our collaborators at Durham.
Abstract: Herein, we expose how the antagonistic relationship between solid-state luminescence and photocyclization of oligoaryl alkenes chromophores is modulated by the conjugation length of their alkenyl backbones. Heptaaryl cycloheptatriene molecular rotors exhibit aggregation-induced emission characteristics. We show that their emission is turned off upon breaking the conjugation of the cycloheptatriene by epoxide formation. While this modification is deleterious to photoluminescence, it enables formation of extended polycyclic frameworks by Mallory reactions. We exploit this dichotomy (i) to manipulate emission properties in a controlled manner and (ii) as a synthetic tool to link together pairs of phenyl rings in a specific sequence. This method to alter the tendency of oligoaryl alkenes to undergo photocyclization can inform the design of solid-state emitters that avoid this quenching mechanism, while also allowing selective cyclization in syntheses of polycyclic aromatic hydrocarbons.
Our manuscript on ‘Supramolecular Repair of Hydration Lubrication Surfaces’ has just been published in Chem.
We have shown that selective host–guest interactions can be exploited to assemble a monolayer of polymers on surfaces. The phosphorylcholine polymer structures attract water, giving a low-friction surface by virtue of ‘hydration lubrication’. The host–guest interaction acts as a weak link in the assembly, such that excessive mechanial wear causes reversible dissociation rather than irreversible covalent cleavage. The lubricating properties of the monolayer can then be restored as more polymer self-assembles on the surface and the weak links are reestablished.
Congratulations to our postdoc Yulong who led the work along with our fantastic collaborators in the Zhang, and Avestro groups.
SOFI PhD student Phil Hope has successfully completed his PhD viva. Phil has been a member of the Avestro Group at Durham University, working closely with the McGonigal Group during the past few years. Great job Dr Hope and good luck as a postdoc in Zurich!
Congratulations to Aisha, who was recently selected as a finalist for the L’Oréal-UNESCO For Women in Science Rising Talents award. The international awards programme has promoted women in scientific research on a global scale since 1998. After presenting a research proposal and attending a ceremony at the Houses of Parliament, she came away with the Highly Commended Award. Well done Aisha!
Postdoc group member Aisha has been selected as one of the 2021 Merck Research Awards Underrepresented Chemists of Color. The award is for underrepresented groups in chemistry including third year chemistry graduate students (minimum) or postdocs.
Aisha applied for the award while working at Dartmouth College in the US and has since returned to Durham. Aisha will receive a Merck mentor and networking opportunities, as well as travel funds for participation to the 2021 Merck Award Symposium where Aisha will present her research.
Congratulations to Aisha and all of this year’s awardess!
Paul was highly commended in the annual Postgrad Awards from FindaPhD.com in the category of PhD Supervisor of the Year.
See the announcment from FindaPhD here.
