Hosted Catalysts - Supramolecular Cage Determined Selectivity

Lead Research Organisation: Heriot-Watt University
Department Name: Sch of Engineering and Physical Science

Abstract

This is a research project in Chemistry. The project aims to utilise supramolecular catalysis to make tuneable, functional and applicable molecular cages capable of enhancing catalytic processes, with particular focus on using gold(I) catalysts , the linear nature of which has made the control of product enantioselectivity, regioselectivity and stereoselectivity particularly challenging, and singlet oxygen, whose reactivity is often not regio-or enantio-selective. This joint experimental/computational project will combine two groups core skills: supramolecular chemistry (Lloyd) and catalytic computational chemistry (Macgregor).

Planned Impact

Catalysis is an inherently transformative field and the single most powerful method to reduce cost, energy demand and ensure sustainable fine and commodity chemical manufacture. On a grander scale, we will advance the UK economy, security and health through the development and understanding of catalysis. Through an intensive training programme we will ensure optimal use and recovery of our critical resources, exploit new long-term sustainable resources and feedstocks and will make chemical manufacture fit for future generations. Above all we will develop technologies offering a step-change in resource management and utilization. Specific impacts include:
Industry: The UK is an emerging leader in chemical sustainability. Critical Resource Catalysis is thus inherent to the growth of a technology-driven UK economy. In 2007, the growing chemical industry supported 6 million jobs and 21% of the UK GDP. World-class academic researchers, a broadly educated PhD cohort, inherent industrial collaboration and a holistic training environment will deliver unique individuals and scientific outputs for the chemical industry and beyond. Over 95% of our PhD students have continued their scientific efforts, sharing expertise in postdoctoral and industry positions: we produce exceptionally valued workers. The enhanced training provision provided by this CDT ensures even greater demand. Our training is intrinsically linked to industry and private sector parties, delivering core scientific knowledge and translational skills. With expertise in delivering critical innovations to industry, CRITICAT will become the hub for business and industry collaboration, consultation and discovery in the UK and beyond.
Policymakers: Global governments are recognising how important resources are to quality of life. The UK is committed to policies that demand the development of new technologies to facilitate a sustainable lifestyle, including the decarbonisation of energy supplies and the recycling of products, in particular those which contain a critical resource. With a cohort versed in the scientific and sociological arguments surrounding these issues further equipped to tackle future scientific challenges we will supports and strengthens the policies set out by the UK government and will serve as a champion for clear policy direction in the future.
Public: Educating not only our cohort but the general public about the importance of Critical Resource Catalysis is essential. We will engage with beneficiaries, from general audiences to UK HEIs, on our finite resources, their economic impacts and the societal benefits of a sustainable chemical industry. Public science demonstrations, focusing on the chemistry and engineering of critical resources, their uses in today's leading technologies, and the exploitation of the catalytic chemical sciences in a sustainable lifestyle will be led by the cohort to provide the public with a balanced and reasoned view of our contributions. With extensive expertise in public engagement, our team of educators and leaders will drive engagement activities forward and train our cohorts to develop as broad-skilled champions of chemistry and catalysis.
Dynamic researchers: This CDT will deliver at least 80 newly qualified PhD scientists and engineers who are trained in catalysis, the key driver behind sustainable chemical technologies. The students will undertake an exceptionally broad training regime enhanced well beyond a traditional PhD programme. Combined with state-of-the-art research projects, the collaborative interactions intrinsic throughout the CDT will yield great foundational and transferable skills for both researchers and institutions. They will learn business, managerial and communication skills from bespoke training, collaborative science and industry placements. Long-term impact will be ensured through our cohorts' entry into the global workforce and our universities commitment to improved collaboration and pedagogy.

Publications

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Description The beginning of this year (03/2018) was marked by the departure of my initial main supervisor Dr. Gareth Lloyd, as he moved to another university. Up to that point my main project was centred around the development of Hydroxamic acid based metallo-organic porous cages and their application in catalysis. As Filipe is now my main supervisor, I had to realign my overall project to fit to his research interests (photochemistry, polymers, flow chemistry) and at the same time try to keep the work I had done so far relevant.
As such, we envisioned the development of photoactive metallo-organic cages which can be used to enhance various catalytic processes. As the results from my previous work had shown that the structures that I had made did not produce porous cages but 'deflated' helicate structures, we wanted to make a new motif from scratch. Due to my past placement at the University of Cyprus, I had a contact there (professor), who specialises in the synthesis of 1,2,6-thiadiazineones. Although little research has been done on the photochemistry of those moieties, I suggested that we could use them to develop photoactive cages as their structure is promising. As such, a new collaboration was initiated, and we received some samples for further testing. I quickly found that these compounds can act as very potent photosensitisers and at the same time can undergo an unprecedented ring contraction, mediated by light and oxygen. These results are of high significance, as this is a completely new type of reactivity, and we have since developed its scope and probed its mechanism. We believe that in the following months once the study has been finalised the results will be published at a very high impact journal. At the same time, I am working on making the required derivative for the formation of our target metallo-organic cages.
Moreover, while I was under Gareth's supervision, I had begun to develop a novel amide synthesis protocol mediated by solvent free means (mechanochemistry). Since then this project has been completed and we are planning on submitting it for publication by the end of April. We have found that by using mechanochemistry we could make new unreported amides, bearing benzothiadiazole chromophore moieties which in turn make those amides very potent photosensitisers. I am currently collaborating with Gareth and another student from our group (Mary Jones), in order to develop this new class of photoactive amides.
Exploitation Route So far the aforementioned thiadiazine ring contraction uses green chemistry (light, oxygen) to generate a new type of ring contracted heterocycle. There is one example from the 70's where researchers from Merck tried to access these compounds by a tedious and multistep synthesis, so there might be interest in the pharmaceutical community for these compounds since they could exhibit interesting biological properties.
The work on the metallo organic cages is still underway and it could produce useful photocatalysts that can be used by other researchers. (if they are efficient enough and easy to make).
Sectors Chemicals,Pharmaceuticals and Medical Biotechnology