CrystEngComm Blog

Printing crystalline drugs

12 Feb 2013

A group of UK chemists has used a desktop inkjet printer to prepare a metastable form of the anti-epileptic drug carbamazepine. Co-crystals have been prepared by first depositing very small droplets of template solution followed by droplets of the drug solution, which leads to rapid evaporation and crystallisation. Simon Gaisford of UCL School of Pharmacy, London, who lead the project, told Chemistry World that this polymorph has only been produced previously by layering it molecule by molecule onto a template crystal using vapour deposition.

‘Desktop inkjet printers offer amazing control of droplet position in order to produce photographic images,’ says Gaisford. ‘So in this instance the technology can really be considered to be more advanced than is needed for crystal templating, although it is evident that the smaller the droplet size and printing resolution the better the potential of the technique.’

To read more on this story, please visit Chemistry World. The research article can be accessed below:

Rapid preparation of pharmaceutical co-crystals with thermal ink-jet printing
Asma B. M. Buanz, Richard Telford, Ian J. Scowen and Simon Gaisford
CrystEngComm, 2013,15, 1031-1035
DOI: 10.1039/C2CE26519B

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Halogen bonding: competitive and directional?

08 Feb 2013

By Helen Lunn, Publishing Editor.

This article is HOT as recommended by the referees. And we’ve made it free to access for 4 weeks.

: Hydrogen versus halogen bonding in the solid state

The Gamez group have analyzed halogen–π interactions by a statistical study of the occurrence and directionality of the interactions in the solid-state. They used structures from the Cambridge Structural Database (CSD) in combination with an analytical procedure developed and used previously by the authors for other important interactions like lone pair–π and anion–π interactions. The results clearly demonstrate that halogen bonding to a phenyl ring are directional, and could compete with hydrogen bonding. Read more about competition and directionality in the solid state for FREE at:

Halogen-phenyl supramolecular interactions in the solid state: hydrogen versus halogen bonding and directionality
Tiddo J. Mooibroek and Patrick Gamez
CrystEngComm, 2013, 15, 1802-1805
DOI: 10.1039/C2CE26853A

Other related reading from the same group includes:

Anion–arene and lone pair–arene interactions are directional
Tiddo J. Mooibroek and Patrick Gamez
CrystEngComm, 2012, 14, 1027-1030
DOI: 10.1039/C1CE05946G

How directional are D–H phenyl interactions in the solid state (D = C, N, O)?
Tiddo J. Mooibroek and Patrick Gamez
CrystEngComm, 2012, 14, 8462-8467
DOI: 10.1039/C2CE26205C

Acid-terminated hybrid POMs

06 Feb 2013

By Jennifer Newton, Publishing Editor.

This article is HOT as recommended by the referees. And we’ve made it free to access for 4 weeks.

Using linear, rather than cyclic, anhydrides was key to synthesising the carboxylic acid functionalised hybrid polyoxometalates

Leroy Cronin and colleagues at the University of Glasgow report a high yield synthesis of carboxylic acid functionalised clusters by reacting Mn-Anderson hybrid polyoxometalates, substituted by an amine group, with anhydride precursors. The terminal acid groups make it possible for the clusters to bind to hydrophilic glass surfaces. Developing understanding of the surface interactions of these hybrids may have potential implications in the development of hybrid based thin films for solar cells.

Download the paper today to find out more…

Programming the assembly of carboxylic acid-functionalised hybrid polyoxometalates
Marie Hutin, Carine Yvon, Jun Yan, Andrew Macdonell, De-Liang Long and Leroy Cronin
CrystEngComm, 2013
DOI: 10.1039/C3CE26816K, Paper

You may also be interested in the 2012 Dalton Transactions Polyoxometalates themed issue, that was guest edited by De-Liang Long and Leroy Cronin.

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Small crystals with big prospects – magnetite composites as candidates for energy storage

29 Jan 2013

By Matthew Cude, Development Editor.

This article is HOT as recommended by the referees. And we’ve made it free to access for 4 weeks.

In their Hot Article, Qiang Shen and colleagues from Shandong University report the generation of Fe₃O₄–C composites via the evolution of orthorhombic FeOCl. The crystals display some interesting electrochemical properties which make them potential candidates for next generation lithium ion batteries (LIBs).

We use LIBS in portable electronic devices such as phones and computers and LIB development has sparked a great deal of interest among materials scientists and crystal engineers alike.

Take a look at the results of the team’s research by downloading the article below, which is free to access for 4 weeks.

A chemical composition evolution for the shape-controlled synthesis and energy storage applicability of Fe₃O₄–C nanostructures
Fenfen Xu, Wenpei Kang, Xinxin Wang, Rui Liu, Chenhao Zhao and Qiang Shen

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Crystals aim to light up dark matter

16 Jan 2013

By Kate Bandoo, Publishing Assistant.

German scientists hunting dark matter are set to produce half a tonne of high-purity calcium tungstate for their detectors, one 1kg crystal at a time. The CRESST-II experiment based in Gran Sasso, Italy is currently seeking this enigmatic substance, thought to explain the universe’s structure, with 10kg of calcium tungstate (CaWO4). Now Andreas Erb and Jean-Côme Lanfranchi are preparing crystals for its larger successor EURECA, which will begin operation in the French Alps in 5–10 years.

Gravitational effects suggest as-yet-unobserved dark matter in the universe outnumbers more familiar atomic matter four to one. Erb, Lanfranchi and their colleagues are hunting leading theoretical candidates, Weakly Interacting Massive Particles (WIMPs). That name reflects their size – up to a lead atom’s mass – and the limited interaction with atomic matter that makes them hard to find, or ‘dark’. ‘They have to interact weakly to agree with the matter needed,’ says Richard Gaitskell from Brown University in the US, who isn’t involved in the calcium tungstate experiments.

Calcium tungstate crystals, formed at around 1600°C, can be used to detect dark matter © Andreas Heddergott/TU Munich

To read the full article please visit Chemistry World.

Growth of High-Purity Scintillating CaWO4 Single Crystals for the Low-Temperature Direct Dark Matter Search Experiments CRESSTII and EURECA
Andreas Erb
CrystEngComm, 2013, Accepted Manuscript
DOI: 10.1039/C2CE26554K

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Halogen vs. hydrogen bonding

16 Jan 2013

By Helen Lunn, Publishing Editor.

This article is HOT as recommended by the referees. And we’ve made it free to access for 4 weeks.

Competing hydrogen-bond and halogen-bond donors in crystal engineering

In this HOT article by Aakeröy et al, relevant hydrogen-bond and halogen-bond acceptors and donors were selected to study the competition between these two molecular interactions in supramolecular assembly. Twelve co-crystals were synthesized based on two different azobipyridines as acceptors and six donor molecules possessing both hydrogen-bond and halogen-bond moieties. The key conclusions which could be drawn from the study were: (i) the hydrogen-bond is the principal driving force in the formation of 3,3′-azabipyridine co-crystals whereas hydrogen and halogen bonds do indeed compete in the formation of the 4,4′-azabipyridine co-crystals; (ii) the iodine donor appears to be a better halogen-bond donor than bromine; and (iii) the three different hydrogen-bond donors studied (–COOH, –OH and –CN(R)OH) behave similarly.

December Crystal Clear: A Crystal Snowflake

14 Jan 2013

By Matthew Cude, Development Editor.

SEM image of a dendritic copper(I) oxide crystal deposited on an ITO substrate in a stirred electrolyte

Last month’s crystal clear is a wintry image of a Cu₂O crystal.

The group from the Taiyuan University of Technology were investigating the growth of Cu₂O crystals along the <110> direction. Copper(I) oxide is a p-type semi-conductor with applications from solar-cells to water splitting and catalysis. The physical properties of Cu₂O crystals are greatly influenced by their morphology, which has generated considerable interested among crystal engineers.

The study by Wei Liang et al. reports the synthesis of dendritic crystals using a pulsed galvanostatic method and an electrolyte containing only Cu(Ac)₂, the controlled growth along the <110> directions produces these eye-catching nano-structures. The team reported the full details of their research in Issue 23 of CrystEngComm. You can download the full article below, which is free to access for 4 weeks.

Are you a budding crystal engineer? Keep up to date with latest developments by following us on twitter @CrystEngComm.

Crystallization behavior and formation mechanism of dendrite Cu₂O crystals
Jinbo Xue, Wei Liang, Xuguang Liu, Qianqian Shen and Bingshe Xu

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IUPAC Provisional Recommendations on Metal-Organic Framework and Coordination Polymer Terminology

08 Jan 2013

By Matthew Cude, Development Editor.

The IUPAC task group: Coordination polymers and metal organic frameworks: terminology and nomenclature guidelines have published provisional recommendations. The article can be accessed directly here and any comments can be directed to the task group chair, Professor Lars Öhrström.

The task group was set-up in 2009 to document, analyse and evaluate the use of nomenclature and terminology in the areas of coordination polymers and metal-organic frameworks. As well as meeting on three occasions the group also published a Highlight article detailing the need for terminology guidelines and the provisional recommendations, which include the following definitions:

Term	Definition
Coordination Polymer	A coordination compound continuously extending in 1, 2 or 3 dimensions through coordination bonds
Coordination Network	A coordination compound extending, through coordination bonds, in 1 dimension, but with cross-links between two or more individual chains, loops or spiro-links, or a coordination compound extending through coordination bonds in 2 or 3 dimensions
Metal-Organic Framework	Metal-Organic Framework, abbreviated to MOF, is a Coordination Polymer (or alternatively Coordination Network) with an open framework containing potential voids

There are also recommendations on net and network topology, topology descriptors, nomenclature and the use of other terms (which explicitly discourages the term “hybrid organic-inorganic materials”)

Download the full article for the complete recommendations and take a look at the Highlight article published last year

Coordination polymers, metal–organic frameworks and the need for terminology guidelines
Stuart R. Batten, Neil R. Champness, Xiao-Ming Chen, Javier Garcia-Martinez, Susumu Kitagawa, Lars Öhrström, Michael O’Keeffe, Myunghyun Paik Suh and Jan Reedijk
CrystEngComm, 2012, 14, 3001-3004
DOI: 10.1039/C2CE06488J

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Releasing the electronic potential in aluminium nitride

13 Dec 2012

By Jennifer Newton, Publishing Editor.

This article is HOT as recommended by the referees. And we’ve made it free to access for 4 weeks.

Photo of free-standing AlN wafer

The use of aluminium nitride in solid-state optoelectronic devices has been hindered by high defect levels limiting the output power, efficiency and lifetimes of mid-UV LEDs. Now, there is a possible solution, thanks to the method described in this HOT CrystEngComm paper.

R. Radhakrishnan Sumathi from Ludwig Maximilians University reports a physical vapour transport growth method using silicon carbide as a foreign substrate. The result is a more homogeneous structure than afforded by previous methods with uniform levels of defects and impurities across the wafer.

Read more now…

Bulk AlN single crystal growth on foreign substrate and preparation of free-standing native seeds
R. Radhakrishnan Sumathi
CrystEngComm, 2013
DOI: 10.1039/C2CE26599K

Are you following us on Twitter? @crystengcomm

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Crystallising Plaster of Paris

07 Dec 2012

By Fiona McKenzie, Executive Editor.

It wasn’t so long ago when Plaster of Paris was used for plaster bandages when a patient broke their arm or leg. Nowadays, synthetic polymer materials tend to be used for such purposes but Plaster of Paris still finds wide use for building materials.

When Plaster of Paris (also known as bassanite or for those of us chemists not so familiar with this material, CaSO₄.1/2H₂O) is mixed with water, the less soluble compound, gypsum is formed (CaSO₄.2H₂O). This precipitates out of solution to produce interlocking, needle-like crystals. There have been many studies looking into this crystallisation reaction, however most real-life applications rely on crystallisation onto a solid support and as such, the studies to date are arguably not so industrially-relevant.

Now, in their latest CrystEngComm article, Stephen Mann and colleagues from the University of Bristol report on Plaster of Paris crystallisation onto inert films of cellulose. They found that the films can be made active by pre-treating them with a solution of Ca²⁺. Mann et al. say that such pre-treatment may have important implications for using Plaster of Paris materials in a wide range of industrial applications.

To read more about this work, download the article:
Calcium sulfate hemihydrate-mediated crystallization of gypsum on Ca²⁺-activated cellulose thin films
Stephen Mann, Mei Li, Tomi Nissinen and Nelly Brielles
CrystEngComm, 2013

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CrystEngComm Blog

Printing crystalline drugs

Halogen bonding: competitive and directional?

Acid-terminated hybrid POMs

Small crystals with big prospects – magnetite composites as candidates for energy storage

Crystals aim to light up dark matter

Halogen vs. hydrogen bonding

December Crystal Clear: A Crystal Snowflake

IUPAC Provisional Recommendations on Metal-Organic Framework and Coordination Polymer Terminology

Releasing the electronic potential in aluminium nitride

Crystallising Plaster of Paris

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