CrystEngComm Blog

Metal organic frameworks (MOFs) are porous materials with a high surface area. This makes them useful  for processes such as catalysis and gas storage, including hydrogen storage, which is crucial for environmentally friendly energy applications.

Nevertheless, many MOF structures can only hold onto H₂ molecules at very low temperatures and concentrations. To enable the MOF to hold onto H₂ molecules at higher temperatures and concentrations, Lalonde and colleagues have synthesized MOFs with a zwitterionic structure, where the negatively charged Zn₂(CO₂)₅ groups are separated from the positive imidazole tetra acid groups. The material shows enhanced H₂ adsorption, and is a good candidate for further optimisation. The zwitterionic design can also be applied to synthesizing other MOF structures or porous materials  for use in H₂ storage.

Read their article to find out more:

A zwitterionic metal–organic framework with free carboxylic acid sites that exhibits enhanced hydrogen adsorption energies
Marianne B. Lalonde, Rachel B. Getman, Jeong Yong Lee, John M. Roberts, Amy A. Sarjeant, Karl A. Scheidt, Peter A. Georgiev, Jan P. Embs, Juergen Eckert, Omar K. Farha, Randall Q. Snurr and Joseph T. Hupp
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE40198G

Lotus leaves are superhydrophobic due to their microstructure, and Shuxi Dai and colleagues have pioneered a method of replicating this in a ZnO film by a ‘bottom up’ method. Using real lotus leaves as templates, they replicated the microstructure on ZnO films. The material consists of an array of micropillars, on which further nanostructures form after a second hydrothermal treatment. Depending on the solution used in the second stage, properties of the final structure, such as hydrophobicity, can be tuned.

Many natural materials have microstructures that give them desirable chemical or mechanical properties, and the method presented in this paper enables scientists to mimic them easily on other materials such as functional metal oxides.

Find out more from their article.

Biomimetic fabrication and tunable wetting properties of three-dimensional hierarchical ZnO structures by combining soft lithography templated with lotus leaf and hydrothermal treatments
Shuxi Dai, Dianbo Zhang, Qing Shi, Xiao Han, Shujie Wang and Zuliang Du
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE40238J

Self-assembled Fe₃O₄ superstructures have unique electric and magnetic properties, such as allowing the material to exceed the ‘‘superparamagnetic limit’’ found in Fe₃O₄ with a less well defined structure. Using a novel way of synthesising Fe₃O₄ nanoflakes via an ionic liquid-assisted solvothermal process, Xiaodi Liu and colleagues have made self-assembled Fe₃O₄  structures from nanoparticles. These nanoflakes have a good monodispersity and magnetic properties that are not seen in material made by other synthetic methods, making them good candidates for applications such as high density magnetic recording.

In this study, the authors have also explored how different growth conditions affect the final structure, thus providing a method for optimising the process for making other self-assembled nanomaterials using ionic liquids.

Find out more by downloading their paper:

Ionic liquid-assisted solvothermal synthesis of oriented self-assembled Fe₃O₄ nanoparticles into monodisperse nanoflakes
Xiaodi Liu, Xiaochuan Duan, Qing Qin, Qinglun Wang and Wenjun Zheng

CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE00035D, Communication

By looking at the structures of halogen-bonded infinite chains with two diiodoperfluoroalkanes and a bent bis(pyrid-4′-yl)oxadiazole, Giuseppe Resnati and colleagues have investigated the influence that halogen bond directionality has on supramolecular design.  The bent geometry of the pyridyl pendant rings in the structures were found to translate into the angle between the formed halogen bonds, taking precedence over parameters that might affect the crystal packing.

Download their HOT CrystEngComm communication today to find out more…

Halogen bond directionality translates tecton geometry into self-assembled architecture geometry
Marco Saccone, Gabriella Cavallo, Pierangelo Metrangolo, Andrea Pace, Ivana Pibiri, Tullio Pilati, Giuseppe Resnati and Giancarlo Terraneo
CrystEngComm, 2013
DOI: 10.1039/C3CE40268A, Communication

This communication is part of a themed issue on Halogen bonding (guest edited by Giuseppe Resnati, Mark Taylor and William Pennington) which is due to go online next week.

Producing nanotubes of biocompatible hydroxyapatite by continuous hydrothermal synthesis
Edward Lester, Selina V. Y. Tang, Andrei Khlobystov, Vanessa Loczenski Rose, Lee Buttery and Clive J. Roberts

CrystEngComm, 2013, Advance Article, DOI: 10.1039/C3CE26798A

Free to access until 21st April

Knowledge-based hydrogen bond prediction and the synthesis of salts and cocrystals of the anti-malarial drug pyrimethamine with various drug and GRAS molecules
Amit Delori, Peter T. A. Galek, Elna Pidcock, Mohit Patni and William Jones

CrystEngComm, 2013,15, 2916-2928, DOI: 10.1039/C3CE26765B

Free to access until 21st April

Thermodynamics and nucleation of the enantiotropic compound p-aminobenzoic acid
Michael Svärd, Fredrik L. Nordström, Eva-Maria Hoffmann, Baroz Aziz and Åke C. Rasmuson

CrystEngComm, 2013, Advance Article, DOI: 10.1039/C3CE26984A

Free to access until 21st April

 Andrew Farrell and colleagues have conducted the first ever ultra-low temperature (2K) study of the crystal structure of the single molecule magnet, [Mn₁₂OAc], [Mn₁₂O₁₂(O₂CMe)₁₆(H₂O)₄]•4H₂O•2MeCO₂H. This is the temperature where the molecule exhibits its most interesting properties.

Using a combination of single crystal X-ray diffraction and neutron diffraction, they were able to provide a better model of the molecular structure and to explain the special quantum properties of the single molecule magnet. A study of the species with the solvents removed also yielded further clues to the nature of the disorder in the solvated species.

Find out more by downloading the full paper now:

Ultra-low temperature structure determination of a Mn₁₂ single-molecule magnet and the interplay between lattice solvent and structural disorder
Andrew R. Farrell, Jonathan A. Coome, Michael R. Probert, Andres E. Goeta, Judith A. K. Howard, Marie-Helene Lemee-Cailleau, Simon Parsons and Mark Murrie
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE00042G

In this HOT article, Shengchun Yang and co-workers describe the preparation of porous Ag nanocubes by synthesizing Ag₃PO₄ nanocubes and using them as hard templates. With the addition of strong reducing agents, Ag is reduced in situ to form porous Ag.  The resulting Ag showed good SERS (surface enhanced Raman scattering) properties by detecting nanomolar concentrations of Rhodamine 6G.

Volume shrinkage induced formation of porous Ag sub-microcubes via solid–liquid reaction for SERS

Find out more by downloading the full paper now:

Volume shrinkage induced formation of porous Ag sub-microcubes via solid–liquid reaction for SERS
Xiao Luo, Shaomin Lian, Liqun Wang, Shengchun Yang, Zhimao Yang, Bingjun Ding and Xiaoping Song
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE27089K

You may also be interested in other publications concerning SERS and noble metals from recent studies by the same author:

A new route for the synthesis of polyhedral gold mesocages and shape effect in single-particle surface-enhanced Raman spectroscopy
Jixiang Fang, Sergei Lebedkin, Shengchun Yang and Horst Hahn
Chem. Commun., 2011, 47, 5157-5159
DOI: 10.1039/C1CC10328H

Interface synthesis of gold mesocrystals with highly roughened surfaces for surface-enhanced Raman spectroscopy
Hongjun You, Yuetian Ji, Liang Wang, Shengchun Yang, Zhimao Yang, Jixiang Fang, Xiaoping Song and Bingjun Ding
J. Mater. Chem., 2012, 22, 1998-2006
DOI: 10.1039/C1JM13211C, Paper

Also, keep up to date and follow us on twitter: @crystengcomm

Noriaki Kubota and colleagues have modelled the effects of sensitivity and resolution of a nucleation detector on metastable zone width. 

The metastable zone width has been somewhat ambiguously defined as “the supercooling at which the first crystals or uncontrolled spontaneous crystallisation is detected when the solution temperature is lowered at a constant rate”. In order to pin down the specifics, a couple of groups have defined the metastable zone width as the supercooling that occurs when the number density of crystals reaches a fixed value – which in effect is determined by the sensitivity of the detection method.

To find out what effect the sensitivity and resolution of a detector has on metastable zone width readings, the team have employed analytical and numerical methods. A deeper understanding of this is neccesary to enable better control of crystallisation processes.

Download the article today to find out more…

Analytical and numerical study of detector sensitivity and resolution effects on metastable zone width
Noriaki Kubota, Masanori Kobari and Izumi Hirasawa
CrystEngComm, 2013, 15, 2091-2098
DOI: 10.1039/C2CE26968F, Paper

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

You may also be interested in: 

Competing hydrogen-bond and halogen-bond donors in crystal engineering
Christer B. Aakeröy,  Sheelu Panikkattu,  Prashant D. Chopade and John Desper
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C2CE26747K 

or also on our blog 

Follow us on Twitter:  @crystengcomm

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.