RSC Advances Blog

One needs to seek nature in order to get the idea of sustainability either in daily life or in the chemistry lab. We have been learning since our childhood about plants survival via photosynthesis and humans survival by oxygen. The sun has been the ultimate powerhouse for all the beings on earth.

Photosynthesis is the apotheosis of sustainable chemical reactivity and the sun is one of the main pinnacles towards the target of green chemistry. In the context of sustainable synthetic approaches, photoredox chemistry has emerged as a scientific toolbox for organic transformations due to the tremendous ability to generate reactive intermediates under mild reaction conditions.

Photoredox catalysis depends upon the photoexcitation with visible light to facilitate single electron transfer (SET) and the generation of other intermediates. Sunlight energy could be the essential source for this cause owing to its free, non-toxic and environmentally benign nature. These benefits make photoredox catalysis valuable when designing new catalytic systems with sustainable approaches. However, there are other sources for the photoexcitation although they pose limitations due to high energy requirements and formation of side products. Even though photoredox catalysis has provided powerful methods in synthesis, the cost of photocatalysts and cost of light sources and environmental aspects on the synthesis are yet to be considered.

With the help of a broad range of molecules synthesized in our lab, modeling and utilization, we have been able to understand the potential of molecules for their photoredox catalytic activity. Considering this situation, my recent research focuses on the synthesis of molecules with strong visible range absorption and utilization of sunlight for photoexcitation to carry out various organic transformations via photoredox chemistry. By smartly incorporating the donor and acceptor groups, we are able to synthesize molecules with absorption in the visible region (Fig. 1).

My focus is on understanding the potential of the molecules to catalyze reactions with low energy radiations i.e. solar-driven. The synthesized molecules have been subjected to various experiments and found to be active towards aggregation-induced emission enhancement (AIEE) and solvatochromism phenomenon, reactive oxygen species generation as well as displayed catalytic activity towards reactions such as (i) oxidative homocoupling of benzyl amines (ii) additive free oxidative amidation of aldehydes and (iii) hydroxylation of boronic acids under the presence of sunlight. All you need to get a good transformation is chemicals, a stirrer and the sun. Our group continue to address challenges in this field, exploring more solar-driven chemical transformations.

To find out more, please read:
AIEE Active Nanoassemblies of Pyrazine Based Organic Photosensitizers as Efficient Metal-Free Supramolecular Photoredox Catalytic Systems
Scientific. Reports,2019, 9:1114.

About the Web Writer:

Shruti Dadwal is a Ph.D. candidate in organic chemistry under the supervision of Dr. Vandana Bhalla at Guru Nanak Dev University, Amritsar, India; where she also completed her B.Sc and first class M.Sc in Hons. School Chemistry. Her research focuses on developing new and better donor-acceptor based molecules for sensing, photocatalysis and nanocatalysis. She enjoys music, writing and travelling. You can find her on Twitter @DadwalShrutii.

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From gunpowder to modern energetic materials, the so-called science of explosive research has renovated the potential capability to discover a wide range of novel energetic materials exclusively used in both military and civilian sectors. However, the controversial drama between the properties of energetic materials, namely, the power-safety contradiction, constitutes a great challenge in the design of new energetic materials. The desired energetic materials need to be balanced between these two inherently contradicting properties, which restricts their usage in practical applications, even though many energetic materials are synthesized every year.

Structure-properties-performance inter-relationship of BTO-based energetic materials

In order to obtain a fine balance between the properties of energetic materials, we have studied how the microstructures and intermolecular interactions influence the macroscopic behaviour of explosives. With the help of large-scale clusters, a broad range of theory, modelling and simulations, we have been able to understand the potential capabilities of energetic materials for possible real time applications.

Most of the energetic solids that I have studied are molecular crystals held together by inter-molecular interactions. By smartly incorporating the energetic groups as proton acceptors, we could form the strong hydrogen bonding networks crucial for the construction of high energy density materials. As improved intra- and intermolecular interactions tightly pack the crystal and thereby reduces its volume, the density and stability of the energetic materials is enhanced. This is therefore a highly efficient strategy to improve the performance and stability of explosives. The main objective of our studies is to understand the fundamental physical and chemical properties and the thermodynamic equation of the state of energetic crystals.

My focus is on the understanding of various properties of solid energetic materials using van der Waals density functional methods, including van der Waals interactions, structural stability, pressure induced structural phase transformations and vibrational properties of green energetic materials. In our recent work on a series of 5,5′-bitetrazole-1,1′-diolate based energetic ionic salts, we were able to provide a precise correlation between intermolecular interactions and impact sensitivity of energetic materials, in combination with molecular stability that can be set as a base for molecular and crystal design. In 2018, this work was recognized as a HOT article published in PCCP (1) and more recently, our research demonstrating the importance of high pressure studies was published in RSC Advances (2). Overall, our approach may provide a fundamental knowledge in designing the next-generation explosives, propellants, and pyrotechnics prior to the actual experiments.

References:

1. Moses Abraham, Vikas D. Ghule and G. Vaitheeswaran, Phys. Chem. Chem. Phys., 20, 29693, 2018
2. Moses Abraham, RSC Adv., 2020,10, 24867-24876

About the Web Writer:

Dr. B. Moses Abraham recently received his Ph.D from the University of Hyderabad, India. He obtained a Bachelor of Science degree from Noble College, Machilipatnam, which is one of the first four educational institutions opened in India by the British Government in 1843.  Moses Abraham has been inducted as an Associate Member in Royal Society of Chemistry. His recent work on BTO-based energetic salts was recognized as HOT article for the year 2018 by Physical Chemistry Chemical Physics. He has received various prestigious travel grants including the Royal Society of Chemistry and Science and Engineering Research Board travel grants to present his research on international scientific platforms. You can find him on Twitter @mosesabrahamb.

Submit to RSC Advances today! Check out our author guidelines for information on our article types or find out more about the advantages of publishing in a Royal Society of Chemistry journal.

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Conference organisers all over the world have unfortunately had to cancel or postpone their plans in response to the deadly COVID-19 pandemic. However, some conference organisers made last-minute decisions to hold their conferences online. I have managed to attend two online conferences during lockdown; CEMWOQ 6.5 (The 6.5th Crystal Engineering and Emerging Materials Workshop of Ontario and Quebec) and CEFMC2020 (Crystal Engineering: From Molecule to Crystal 2020), which were held virtually via zoom from Canada and India respectively. Both conferences were attended by participants interested in crystals and crystalline materials from all parts of the world. Overall, they were extremely welcoming, well-organised and the feedback both during the conference and afterwards on twitter has been very positive.

Twitter has been extremely useful during lockdown to keep up with literature, discover useful webinars and it is where these online conferences were mostly advertised. It also provided a platform for posters to be presented prior to CEFMC2020, allowing participants and judges to browse at their own pace. In contrast, CEMWOQ 6.5 organisers made use of breakout rooms on zoom, which allowed the presenters to discuss their posters with other interested participants.

Whilst it is easier to network at normal conferences and meeting in-person is nice, online conferences have the potential to play an important role in improving diversity and inclusivity in science. Both CEMWOQ 6.5 and CEFMC2020 were completely free to attend and anyone who wanted to participate could register until capacity was reached. This provides an opportunity for postdocs, PhD students like me and even keen undergraduates to attend conferences and become inspired by incredible talks that they may have otherwise been unable to attend for financial or personal reasons. Even speakers with poor internet connections were able to present by providing pre-recorded talks.

One of the only negatives of the online conference is the time-zone difference. Depending on where you are based, a very early start or late night may be required, but that’s a reasonable sacrifice to learn about the fantastic research being done within the community.

Online conferences may become more commonplace post-COVID-19 now that they have been tried and tested. Whilst normal (in-person) conferences shouldn’t be completely replaced, switching between the online and in-person formats will allow for wider, more inclusive participation and less air travel is always a positive to help protect our planet.

About the Web Writer:

Lee Birchall has recently started his PhD under the supervision of Dr. Helena Shepherd at the University of Kent, where he also completed his MSc under the supervision of Dr. Stefano Biagini. He obtained a first class BSc at University College London. He enjoys music, languages and windsurfing and you can find him on Twitter at @LTBIRCH.

Submit to RSC Advances today! Check out our author guidelines for information on our article types or find out more about the advantages of publishing in a Royal Society of Chemistry journal.

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I have recently started my PhD – studying spin-crossover complexes, and my synthetic approach is largely focused on the use of mechanochemistry (1). The general response to me saying that I’m busy is: ‘don’t you just grind stuff?’, and the answer is no because I have analysis to do like everyone else. As mechanochemistry is a (mostly) solid state technique, powder X-ray diffraction is a go-to technique for product analysis. Comparison to starting materials can give an indication that a reaction has taken place, and then the detailed analysis can begin.

Elucidation of the structure of novel compounds which are not compatible with NMR, is often facilitated by single crystal XRD (SCXRD). The data from SCXRD can be used to simulate powder patterns for comparison with the mechanochemically synthesized powders.

Colour changes during grinding can also be indicative of reaction success. Therefore, mechanochemistry can allow for rapid screening of a huge number of different reactions in the search for interesting materials. However, don’t be too quick to dismiss an unsuccessful reaction if you haven’t tried liquid-assisted grinding (LAG). Whilst mechanochemistry is typically a solid-state technique, the addition of a small quantity of appropriate solvent (< 1 equiv. in µL per mg) (2,3) can be useful to get the reaction started.

My first experience with mechanochemistry quickly taught me that retrieving powder from a mortar is not easy, no matter how much it is scraped by a spatula. In the spirit of minimizing waste, the un-scrapeable powder is dissolved in a small amount of appropriate solvent and divided up into numerous vials, where techniques such as vapour diffusion and slow evaporation are used to harvest crystals.

I am still new to the world of mechanochemistry and have a lot to improve on, but it has opened my eyes to a synthetic approach that isn’t regularly seen in undergraduate studies and even research labs. It’s a promising area with a lot of applications, where the methodology could easily be manipulated for manufacturing purposes. However, if you are interested in trying some mechanochemistry, it is important to be aware of the potential hazards associated with the neat grinding of certain compounds, especially those which may explode!

References:

1              J. H. Askew and H. J. Shepherd, Chem. Commun., 2017, 54, 180–183.
2              T. Friić, S. L. Childs, S. A. A. Rizvi and W. Jones, CrystEngComm, 2009, 11, 418–426.
3              D. Tan and F. García, Chem. Soc. Rev., 2019, 48, 2274–2292.

About the Web Writer:

Lee Birchall has recently started his PhD under the supervision of Dr. Helena Shepherd at the University of Kent, where he also completed his MSc under the supervision of Dr. Stefano Biagini. He obtained a first class BSc at University College London. He enjoys music, languages and windsurfing and you can find him on Twitter at @LTBIRCH.

Submit to RSC Advances today! Check out our author guidelines for information on our article types or find out more about the advantages of publishing in a Royal Society of Chemistry journal.

Keep up to date with our latest HOT articles, Reviews, Collections & more by following us on Twitter. You can also keep informed by signing up to our E-Alerts.

Global energy demand grows very fast, while fossil fuel reserves decrease. For this reason, enormous efforts are focused on the production of new renewable, clean, safe and reliable forms of energy to ensure a sustainable future. At the same time, it is necessary to include energy vectors that allow storing and transporting said energy to be used when and where it is required. Lithium-based batteries are currently presented as one of the best systems to meet this need. Although its use in portable electronic devices is already established, the implementation in stationary energy accumulation and in the electric vehicle sector demands a notable increase in its energy density. That is why these new demands make a primary aspect, and which is currently a topic of study worldwide, to the development of materials with which the components for rechargeable lithium batteries are produced.

In the case of lithium-sulfur batteries, metallic lithium is used as the active material for the anode and sulfur for the cathode. After several electrochemical charge and discharge cycles, small branches form on the surface of the lithium metal electrode, called dendrites. These ramifications can cause a short circuit leading to spontaneous discharges, causing rapid heating and even fire, making them unsafe. Therefore, new investigations have found promising alternatives to avoid these drawbacks, based on the deposition of protective polymers on the surface of the metallic Li anode and the study of its effect on the degradation of the material properties. The polymers to be used are polymeric ionic liquids. Ionic liquids are molten salts whose melting temperature is less than 100°C. Considering the non-flammability and non-volatility properties of ionic liquids, they make reasonable alternatives as part of electrolytes because they offer important improvements, for example, in terms of safety. For this reason, the imim-DEHP protic ionic liquid synthesized for the first time by me and reported in the paper RSC Advances, 2017, 7, 44743 will be used, since we have observed that, with small amounts of water, imim-DEHP has the ability to form a gel, so it will be used in lithium batteries to coat the lithium anodes. Thus showing the versatility of this amphiphilic ionic liquid, since it forms organized systems in water and in non-polar organic solvents, as well as gels with a small amount of water.

Find out more:

Improvement of the amphiphilic properties of a dialkyl phosphate by creation of a protic ionic liquid-like surfactant
Cristian M. O. Lépori, Juana J. Silber, R. Darío Falcone and N. Mariano Correa
RSC Adv., 2017, 7, 44743

About the Web Writer:

Cristian M. O. Lépori is Doctor in Chemical Sciences and currently has a postdoctoral position at the “Enrique Gaviola” Institute of Physics, CONICET, National University of Córdoba (Argentina). He works in the area of nuclear magnetic resonance studying hybrid materials formed with porous matrices and ionic liquids for use in lithium batteries. He likes to plan, organize and carry out science dissemination activities. You can find him on Twitter at @cristianlepo.

Submit to RSC Advances today! Check out our author guidelines for information on our article types or find out more about the advantages of publishing in a Royal Society of Chemistry journal.

Keep up to date with our latest HOT articles, Reviews, Collections & more by following us on Twitter. You can also keep informed by signing up to our E-Alerts.