CrystEngComm Blog

Werner Paulus and colleagues report on studies into low temperature oxygen mobility in terms of anisotropic oxygen in brownmillerite type frameworks.  By using a floating zone method they were able to optimise the paramaters so as to obtain large and homogenous crystals of CaFeO_2.5 that were essential for detailed structural and lattic dynamic studies.  Understanding oxygen mobility in non-stoichiometric perovskites will aid the development of electrolytes in solid-oxide fuel cells which currently work at high temperatures but low temperature conditions would be preferable.

Typical CaFeO2.5 crystals obtained in this study were 120 mm long and had a shiny, silver-black surface with metallic luster.

Download the paper to find out more…

Growth and characterization of large high quality brownmillerite CaFeO_2.5 single crystals
Monica Ceretti, Andrea Piovano, Alain Cousson, Tanguy Berthier, Martin Meven, Giovanni Agostini, Jurg Schefer, Olivier Hernandez, Carlo Lamberti and Werner Paulus
CrystEngComm, 2012
DOI: 10.1039/C2CE25413A

Shearing, bending or brittle?

C. Malla Reddy and colleagues study polymorphic forms of 6-chloro-2,4-dinitroaniline to demonstrate a direct relationship between mechanical properties, crystal structure and tableting behaviour in this HOT CrystEngComm communication.  Understanding the structure-property relationships ocurring in pharmaceuticals and using this knowledge to eliminate inferior active pharmaceutical ingredient properties could play an important role in reducing formulation and manufacturing costs in the industry.

Why not take a look, they will be free to read for 4 weeks.

Direct correlation among crystal structure, mechanical behaviour and tabletability in a trimorphic molecular compound
Partha Pratim Bag,  Miles Chen,  Changquan Calvin Sun and C. Malla Reddy
CrystEngComm, 2012
DOI: 10.1039/C2CE25100K

CrystEngComm, 2012, 14, 2335-2596

You may also be interested in taking a look at our recent themed issue on Crystal engineering and crystallography in the pharmaceutical industry.

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New synthesis route for metal fluorosulphates

Cathodes made from olivine-type LiFePO₄ are currently being investigated for use in batteries thanks to having properties such as high structural stability, low production costs and high theoretical capacities – but they are currently restricted by being unable to provide sufficient voltage.  A possible way to increase the voltage in such a system could be the isostructural replacement of (PO₄)^3- with (SO₄)^2- as well as the introduction of fluorine.

In their CrystEngComm Communication, Yongchun Zhu, Yitai Qian and colleagues have prepared the compound NaFeSO₄F in a single, short step (previous methods have taken more than 40 hours) using a benzene-water azeotrope, which is a mixture of liquids that boils at a constant temperature, maintaining the ratio of constituents. 
Could this method be adapted to synthesise other fluorosulphates in one step, such as LiZnSO₄F or NaZNSO₄F, for use as cathode materials?

Read the Communication to find out more – it’s currently free.

A novel benzene–water azeotrope route to new Na-based metal fluorosulphates NaFeSO₄F and NaFeSO₄F·2H₂O in one minute
Zhengqiu Yuan, Denghu Wei, Yan Wang, Yongchun Zhu, Yitai Qian and Kaibing Tang
CrystEngComm, 2012
DOI: 10.1039/C2CE25155H

Remember you can keep up to date with all the latest news in crystal engineering by liking us on facebook, following us on twitter or signing up to our e-alert service.

Linear halogen bond assembly

Lee Brammer and colleagues report crystal structures of halogen-bonded adducts between diiodoacetylene and nitrogen/oxygen acceptor groups showing the suitability of diiodoacetylene as a ditopic connector. 

The strength in the halogen bond is due to the electron-withdrawing effect from the sp-hybridised carbon atom in diiodoacetyle.  Being able to form such strong intermolecular interactions via such a small linear molecule with two conformationally constrained faces makes diiodoacetylene a useful building block in crystal engineering and supramolecular chemistry.

Read the paper for free…

Diiodoacetylene: compact, strong ditopic halogen bond donor
Catherine Perkins,  Stefano Libri,  Harry Adams and Lee Brammer
CrystEngComm, 2012
DOI: 10.1039/C2CE00029F

Here is a selection of other recent work from Lee Brammer and colleagues…

Different structural destinations: comparing reactions of [CuBr2(3-Brpy)2] crystals with HBr and HCl gas
Guillermo Mínguez Espallargas, Alastair J. Florence, Jacco van de Streek and Lee Brammer
CrystEngComm, 2011, 13, 4400-4404
DOI: 10.1039/C1CE05222E
From themed issue Dynamic behaviour and reactivity in crystalline solids

Synthesis and polymorphism of (4-ClpyH)2[CuCl4]: solid–gas and solid–solid reactions
Iñigo J. Vitorica-Yrezabal, Rachel A. Sullivan, Stephen L. Purver, Caroline Curfs, Chiu C. Tang and Lee Brammer
CrystEngComm, 2011, 13, 3189-3196
DOI: 10.1039/C0CE00628A
From themed issue Reactions in molecular solids and host–guest systems

Effects of halogen bonding in ferromagnetic chains based on Co(II) coordination polymers
Juan M. Clemente-Juan, Eugenio Coronado, Guillermo Mínguez Espallargas, Harry Adams and Lee Brammer
CrystEngComm, 2010, 12, 2339-2342
DOI: 10.1039/C003078C
From themed issue New Talent

Co-crystallisation of nevirapine with maleic acid lead to around a fivefold increase in the aqueous solubility of the drug.

Mino Caira and colleagues have created co-crystals of nevirapine (an antiretroviral drug) with maleic acid that could improve the aqueous solubility of the drug.  Their success was a result of exploiting several hydrogen-bonding functionalities in nevirapine, in particular (but not exclusively) its rigid amide group.

Read their paper to find out more – its currently free.

Co-crystals of the antiretroviral nevirapine: crystal structures, thermal analysis and dissolution behaviour
Mino R. Caira, Susan A. Bourne, Halima Samsodien, Emile Engel, Wilna Liebenberg, Nicole Stieger and Marique Aucamp
CrystEngComm, 2012
DOI: 10.1039/C2CE06507J

Resonant Rutherford backscattering spectrometry along with with ion channeling revealed a uniform growth in both composition and atomic order.

Andrés Redondo-Cubero and colleagues detail the growth of high-quality thick a-plane MgZnO epilayers that can be grown without phase-separation but that contain greater than 50% Mg. The team also constructed Au-MgZnO photodiodes to test if the layers could be used in optoelectronic devices, giving positive results.

To find out more, download this CrystEngComm paper today…

Single phase a-plane MgZnO epilayers for UV optoelectronics: substitutional behaviour of Mg at large contents
A. Redondo-Cubero, A. Hierro, J.-M. Chauveau, K. Lorenz, G. Tabares, N. Franco, E. Alves and E. Muñoz
CrystEngComm, 2012, Advance Article
DOI: 10.1039/C2CE06315H

You might also find this paper interesting:

Density and aspect ratio controlled MgZnO nanowire arrays by spontaneous phase separation effect
Dong Chan Kim, Ju Ho Lee, Sanjay Kumar Mohanta, Hyung Koun Cho, Hyoungsub Kim and Jeong Yong Lee
CrystEngComm, 2011, 13, 813-818
DOI: 10.1039/C0CE00114G

Feng et al. report an interesting route for the preparation of organic-inorganic hybrid materials based on decavanadates in this CrystEngComm HOT Article.  The introduction of complex 1 (H₄V₁₀O₂₈.(HMTA-CH₂OH)₂.6H₂O) into mesoporous carbon foams was shown to improve the electrical behaviour of the foams – findings which could be applied to the preparation of catalyst supports and supercapacitors.

Read more in the article below – free to access until the 2nd December.

Three novel organic-inorganic hybrid materials based on decaoxovanadates obtained from a new liquid phase reaction
Yao-Kang Lv, Zhan-Guo Jiang, Li-Hua Gan, Ming-Xian Liu and Yun-Long Feng
CrystEngComm, 2012
DOI: 10.1039/C1CE05605K