CrystEngComm Blog

Posted on behalf of Jamie Humphrey, Editor

Crystallography is a core science, underpinning many areas of research, and central to crystal engineering. 2014 marks the centenary of the birth of X-ray crystallography and has been proclaimed the International Year of Crystallography. We are delighted to celebrate this important science in CrystEngComm in a number of ways in 2014.

Our celebrations will take the form of the publication of four themed issues dedicated to the best crystal engineering research from four key geographical regions. Keep an eye out for these issues, which will appear throughout the year, covering India (Guest Editor: Professor Rahul Banerjee, CSIR-National Chemical Laboratory, Pune, India), Europe (Guest Editors: Professor Dario Braga, University of Bologna, Italy and Professor Michaele Hardie, University of Leeds, UK), the Americas (Guest Editors: Professor Christer Aakeröy, Kansas State University, USA and Professor Tomislav Friščić, McGill University, Canada) and Asia-Pacific (Guest Editors: Professor Stuart Batten, Monash University, Australia and Professor Jagadese Vittal, National University of Singapore, Singapore).

We also have a number of excellent topic-themed issues planned for the year, illustrating the breadth of crystal engineering research: Functional co-crystals (Guest Editor: Professor Colin Pulham, University of Edinburgh, UK), Structural macrocyclic supramolecular chemistry (Guest Editors: Professor Len Barbour, University of Stellenbosch, South Africa, Professor Len MacGillivray, University of Iowa, USA and Professor Kari Rissanen, University of Jyväskylä, Finland), Nanoparticle assemblies (Guest Editors: Professor Marie Paule Pileni, UPMC, Paris, France, Professor P. Davide Cozzoli, Università del Salento & National Nanotechnology Laboratory, Italy and Professor Nicola Pinna, Humboldt-Universität zu Berlin, Germany), and Nanocrystal growth via oriented attachment (Guest Editors: Dr R. Lee Penn, University of Minnesota, USA, Dr Hengzhong Zhang, University of California, Berkeley, USA, Dr Zhang Lin, State Key Laboratory of Structural Chemistry, China and Dr Helmut Cölfen, University Konstanz, Germany). These follow the themed issues published in 2013, details of which are in Table 1.

Table 1 2013 themed issues, representing the breadth of crystal engineering

Continuing the International Year of Crystallography celebrations, the Royal Society of Chemistry, in partnership with Calcutta University, Jadavpur University and IISER-Kolkata, will organise a symposium on structural chemistry in November in India. We will also participate in a global experiment for school children involving crystals. Keep an eye out for more information about the symposium and the global experiment as they develop.

In 2013 a number of people joined our Editorial Board, bringing with them expertise and experience of their particular research fields. Joining Editorial Board Chair, Len MacGillivray (University of Iowa, USA), Associate Editors Rahul Banerjee (CSIR-National Chemical Laboratory, India) and Christer Aakeröy (Kansas State University, USA) and Board member Nicola Pinna (Humboldt-Universität zu Berlin, Germany) are Associate Editors Hongjie Zhang (Changchun Institute of Applied Chemistry, China) and Georg Garnweitner (TU Braunschweig, Germany) and Board members Graeme Day (University of Southampton, UK), Tomislav Friščić (McGill University, Canada), Michaele Hardie (University of Leeds, UK), Helmut Cölfen (Universitat Konstanz, Germany) and Pierangelo Metrangolo (Politecnico di Milano, Italy). We very much look forward to our collaborations with them all.

The way we connect with our friends, peers and colleagues is changing, and social media is an important tool for this. CrystEngComm is no different. We have a number of outlets for CrystEngComm via social media, expanding the ways in which people can get involved with the journal. The journal has a Facebook page and Twitter account (why not join our 1000 followers?) and our LinkedIn group is a good way to learn about relevant conferences and other news. Our latest offering is our ‘Crystal Clear’ Pinterest page, illustrating some of the stunning crystal images that are included in the journal.

Fiona McKenzie (Deputy Editor) and I will be attending two conferences in 2014: the Crystal Engineering Gordon Research Conference and the IUCr meeting. An important related meeting is the Faraday Discussion meeting 170 with a focus on Mechanochemistry: From Functional Solids to Single Molecules. The meeting will be in Montreal, Canada in May, and more details are available via www.rsc.org/ConferencesAndEvents/RSCConferences/FD/FD170/index.asp

We were very pleased to support a number of international conferences in 2013 through sponsorship. We also provide support via poster prizes – in 2013, we awarded 10 poster prizes, celebrating the achievements of members of our community in the early years of their academic careers. If you are organising a conference in 2014 and you would like us to sponsor a poster prize, please let us know.

Let us connect you and your work into the world’s leading chemistry community in 2014, the International Year of Crystallography: publish with CrystEngComm!

Have a fantastic 2014!

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Posted on behalf of Josh Campbell, web writer for CrystEngComm

Stony corals are the main reef builders of the planet and responsible for some of the oceans’ most beautiful architecture. However the processes behind their skeleton mineralisation are of some debate. Skeleton formation occurs at the interface of the coral tissue and the skeleton. This area is rich in proteins that are able to bind to water and has the properties of a highly viscous sol. Also observed at this interface is an amorphous organic membrane, which possibly acts as a colloidal gel matrix. Aragonite (a polymorph of CaCO₃) precipitates out of seawater directly at this interface and is controlled by the organic gel matrix. Ionic concentrations are also believed to play a part, with high concentrations of Mg²⁺ favouring aragonite precipitation.

A recent article in CrystEngComm investigates how the organic matrix and the level of diffusion of Mg²⁺ affects the precipitation of CaCO₃ . The authors of the article extracted two matrices from two different species of coral (differing in their reliance on photosynthetic algae) and placed them in a highly viscous agarose gel/sol. They then transported CaCO₃ through using a counter diffusion system (CDS). Interestingly, they discovered that the different molecular compositions of the matrices resulted in different morphologies and crystallisation conditions which they suggest is due to the symbiotic relationship some corals have with photosynthetic algae (which provide the main energy source for calcification). We now know that the presence of Mg²⁺ has a large effect on the conditions needed for supersaturation in the medium as well as the phase selections of CaCO₃ .

The use of CDS has allowed coral biomineralisation of these two coral species to be studied in vitro for the first time.

Read the article now for more information:

Exploring coral biomineralization in gelling environments by means of a counter diffusion system
M. Sancho-Tomás, S. Fermani, S. Goffredo, Z. Dubinsky, J. M. García-Ruiz, J. Gómez-Morales and G. Falini
CrystEngComm, 2014, DOI: 10.1039/C3CE41894D

Josh Campbell is a PhD student, currently at the University of Southampton, UK studying crystal structure prediction of organic semiconductors. He received his BSc from the University of Bradford.

Harnessing light from the sun to drive reactions requires the development of photocatalysts which can both absorb light of the required frequency but also absorb enough of this light to meet the energy demands for the reactions.  To solve this latter problem, silver halide catalysts with silver particles adsorbed on the surface (i.e. AgX@Ag) are a possibility, as these utilise the surface plasmon resonance (SPR) effect to enhance the visible light absorbed.  SPR occurs when electrons from the surface Ag atoms oscillate at the same frequency as the visible light. The degree of oscillation  increases and subsequently increases the energy available to facilitate a chemical reaction.  Unfortunately, forming the AgX@Ag particles can require high temperatures and strong light.

A recent CrystEngComm paper reports a facile synthesis of AgCl@Ag under mild conditions, using the biomaterial agar gel as a matrix.  Diffusion of the reactants is mediated by the matrix and on illumination with visible light, Ag atoms are generated on the surface of the AgCl.  The AgCl@Ag particles produced are in the form of concave cubes.  The authors suggest their mild eco-friendly synthesis method could be used to prepare other functional materials at low cost.

For more details, see the paper:

Biomaterial-assisted synthesis of AgCl@Ag concave cubes with efficient visible-light-driven photocatalytic activity
Pei Hu, Xianluo Hu, Chaoji Chen, Dongfang Hou and Yunhui Huang
CrystEngComm, 2014, DOI: 10.1039/C3CE41925H

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Gwenda Kyd has a PhD in metallocarborane chemistry from the University of Edinburgh.  Other research work includes the spectroscopic study of the structure of glasses and organometallic electron-transfer reactions and the preparation of new inorganic phosphors. Currently she is writing a book on chemicals from plants.

Epichrorohydrin (ECH) is an important reagent in the industrial production of glycerol, epoxy resins and polymers used in the paper and food industries.  However, it is toxic to humans by inhalation, by absorption through the skin and by ingestion – and it is a cancer suspect agent.  Accurate and reliable detection of ECH gas is therefore required so that risks can be monitored and minimised.  Semiconductor materials like tin dioxide (SnO₂) are one possibility – they are highly sensitive to gas absorption but their lack of sensitivity to individual gases is problematic.  One method of improving sensitivity is to dope the material with noble metals.

A new paper describes the preparation of porous SnO₂ materials decorated with 5-15% Ag.  These have a diameter of 4-5 μm and consist of nanosheets.  The ECH sensing properties of the new materials were studied and the 10% doped sample was found to give the best performance.  It showed a fast response and recovery time, high response, good selectivity and a detection limit of 0.5 ppm, rendering it a promising material for use in ECH detection.

For more information see the paper:

Selective epichlorohydrin-sensing performance  of Ag nanoparticles decorated porous SnO₂ architectures
Zhenglin Zhang, Haiyan Song, Shishu Zhang, Junyan Zhang, Wenya Bao, Quanqin Zhao and Xiang Wu
CrystEngComm, 2014, Advance Article
DOI: 10.1039/C3CE41478G, Paper

Gwenda Kyd has a PhD in metallocarborane chemistry from the University of Edinburgh.  Other research work includes the spectroscopic study of the structure of glasses and organometallic electron-transfer reactions and the preparation of new inorganic phosphors. Currently she is writing a book on chemicals from plants.

Posted on behalf of Josh Campbell, web writer for CrystEngComm

Organic superconductivity has been observed in charge transfer complexes since the 1980s. The organic cation is most commonly a tetrathiafulvalene derivative or a polycyclic aromatic hydrocarbon. Typically the charge is transported through 1D π-stacks, which can be thought of as molecular wires. However interactions between neighbouring wires have a large impact on the properties of the bulk. The preparation of insulated molecular wires can allow for better understanding of the 1D charge transport and better electronic properties. In π-stacked materials bulky counter ions are used to separate the stacks which allows for better solubility and survival of strongly cationic species.

A new paper looks at how TMFB ((trifluoromethyl)phenylborate) counter ions affect the crystalline packing seen across a series of organic donors. Two distinct packing arrangements were seen, with some donors adopting π-stacked chains which were well separated by the counter ion. However others showed an isolated cation radical bonding motif. To investigate this the authors looked at the size of the donors in question and showed that the switch between packing is possibly to do with the product of the width and length of the molecule. The authors also investigated the electronic properties of the stacks, some of which showed excellent electronic properties.

Find out more from the paper:

π-Bonded molecular wires: self-assembly of mixed-valence cation-radical stacks within the nanochannels formed by inert tetrakis[3,5-bis(trifluoromethyl)phenyl]borate anions
Sergiy V. Rosokha, Charlotte L. Stern and Jeremy T. Ritzert
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE41719K

Josh Campbell is a PhD student currently at the University of Southampton studying crystal structure prediction of organic semiconductors. He received his BSc from the University of Bradford.

Doping of semiconductor crystals with transition metal ions can create materials with improved optical, magnetic and thermal properties.  These could potentially replace conventional semiconductors in optical devices.  However, as the size and shape of the crystals as well as the dopant need to be controlled to optimise the desired properties, their preparation can prove difficult.  The addition of Cu ions to ZnSe nanocrystals is of interest due to their emission properties, but the large difference in structure between Cu_xSe and ZnSe makes retaining the shape after doping, problematic.

A new paper shows how doping of ZnSe crystals with Cu ions can be achieved under mild reaction conditions, obtaining ultrathin nanorods.  This is achieved by preparing  ZnSe nanorods then adsorbing Cu ions onto the surface and finally growing a thin shell of ZnSe on top, as shown in the figure below. The process, termed growth-doping, maintains the shape of the rods during the doping process.  The optical properties of the 1% Cu doped rods give a quantum yield of 7% and the emission is retained for weeks in air, suggesting it may have potential for use in optical devices.

For more information see the paper:

Facile synthesis and optical properties of ultrathin Cu-doped ZnSe nanorods
Shufang Kou, Tingting Yao, Xiaofeng Xu, Rui Zhu, Qing Zhao and Jian Yang
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE41493K

Gwenda Kyd has a PhD in metallocarborane chemistry from the University of Edinburgh.  Other research work includes the spectroscopic study of the structure of glasses and organometallic electron-transfer reactions and the preparation of new inorganic phosphors. Currently she is writing a book on chemicals from plants.