Synthesis of Heavy Cyanide Analogues (CP- and CAs-) for the Design of Novel Prussian Blue Analogues

Although cyanide is most well known for being a potent poison, it is a fundamental chemical building block and an important component of a large number of non-toxic materials. For example, cyanide-containing materials are commonly used in disposable gloves, blue paints, and even as anti-caking agents for table salt. Replacing the nitrogen atom in cyanide (CN-) with a phosphorus or arsenic atom would result in cyanide's "heavy analogues", cyaphide (CP-) and cyarside (CPs-). Like cyanide, these heavier analogues have the potential to be utilized in a wide range of applications. However, there is currently no known way to synthesize either cyaphide or cyarside ions, so these applications remain unaccessible.
Previous attempts to synthesize the heavy cyanide analogues have only been successful in making them in non-ionic forms that are unsuitable for subsequent use in materials chemistry. The goal of this project is to develop a method for producing cyaphide and cyarside as ionic salts. These ionic salts would be much more versatile than existing cyaphide and cyarside containing compounds, and would allow the many potential applications of heavy cyanide analogues to be explored.
A particularly exciting application for cyaphide and cyarside would be as components in a class of magnetic materials called Prussian Blue Analogues (PBAs). PBAs are materials consisting of metal atoms connected by cyanide linkers, and can exhibit useful magnetic properties such as the ability to respond to stimuli like heat or light. Significant effort is currently being directed toward optimizing the magnetic behaviour of PBAs for use in technologies such as chemical sensing. A major design constraint that limits current research efforts is that cyanide is the only available ion that is suitable for constructing PBAs. Ionic salts of cyaphide and cyarside would allow heavy cyanide analogues to also be used in PBAs, opening up many possibilities for their development.
This project aims to explore novel methods for synthesizing ionic cyaphide and cyarside salts from the heavy cyanate analogues, an emerging family of compounds that show promise as chemical precursors to the heavy cyanide analogues. This research would enable heavy cyanide analogues to be utilized in designer materials for emerging technologies, and falls within the EPSRC's "Manufacturing the Future" research theme.
Following the development of a synthesis for ionic salts of the heavy cyanide analogues, the next research objective is to use them to make novel PBAs or other similar magnetic materials, and to investigate how they can be utilized to design materials with advantageous magnetic properties.

The primary impact of the OxICFM CDT will be the highly-trained world-class scientists that it delivers. This impact will encompass both the short term (during their doctoral studies), the medium term (subsequent employment) and ultimately the longer timescale defined by their future careers and consequent impact on science, engineering and policy in the UK.

The impact of OxICFM students during their doctoral studies will be measured by the culture change in graduate training that the Centre brings about - in working at the interface between inorganic synthesis and manufacturing, and fostering cross-sector industry/academia working practices. By embedding not only from larger companies, but also SMEs, we have developed a training regime that has broader relevance across the sector, and the potential for building bridges by fostering new collaborations spanning enormous diversity in scientific focus and scale. Moreover, at a broader level, OxICFM offers to play a unique role as a major focus (and advocate) for manufacturing engagement with academic inorganic synthetic science in the UK.

From a scientific perspective, OxICFM will be uniquely able to offer a broad training programme incorporating innovative and challenging collaborative projects spanning all aspects of fundamental and applied inorganic synthesis, both molecular and materials based (40+ faculty). These will address key challenges in areas such as energy provision/storage, catalysis, and resource provision/renewal necessary to enhance the capability and durability of UK plc in the medium term. To give some idea of perspective, the output from previous CDTs in Oxford's MPLS Division include two start-up companies and in excess of 30 patents.

It is not only in the industrial and scientific realms that students will have impact during their timeframe of their doctorate. Part of the training programme will be in public engagement: team-based challenges in resource development/training and outreach exercises/implementation will form part of the annual summer school. These in turn will constitute a key part of the impact derived from the CDT by its engagement with the public - both face-to-face and through electronic/web-based media. As the centre matures, our aspiration is that our students - from diverse backgrounds - will act as ambassadors for the programme and promote even higher levels of inclusion from all parts of society.

For our partners, and businesses both large and small in the manufacturing sector, it will be our students who are considered the ultimate output of the OxICFM CDT. Our programme has been shaped by the need of such companies (frequently expressed in preliminary discussions) to recruit doctoral graduates who can apply themselves to a broad spectrum of multi-disciplinary challenges in manufacturing-related synthesis. OxICFM's cohort-based training programme integrates significant industry-led training components and has been designed to deliver a much broader skill set than standard PhD schemes. The current lack of CDT training at the interface of inorganic chemistry and manufacturing (and the relevance of inorganic molecules/materials to numerous industrial sectors) heightens the need for - and the potential impact of - the OxICFM CDT. Our students will represent a tangible and valuable asset to meet the long-term skills demand for scientists to develop new materials and nanotechnology identified in the UK Government's 2013 Foresight report.

In the longer term, the broad and relevant training delivered by OxICFM, and the uniquely wide perspective of the manufacturing sector it will deliver, will allow our graduates to obtain (and thrive in) positions of significant responsibility in industry and in research facilities/institutes. Ultimately we believe that many will go on to be future research leaders, driving innovation and changing research culture, and thereby making a lasting contribution to the UK economy.