Selective and reversible adsorption of VOCs by a new MOF

A new paper by Yu-Bin Dong et al reports a metal-organic framework (MOF) which not only reversibly adsorbs two different classes of volatile organic compounds (VOCs), but within each class also shows selectivity allowing separation of chemically similar examples.

VOCs are widely used in the chemical industry but their release into the environment is undesirable, as they can cause damage both to the environment and to human health.  Porous materials such as MOFs are attractive as potential adsorbents of VOCs and could also allow separation of examples with similar boiling points, which proves difficult by other methods such as distillation.

The new MOF consists of ditriazole-N-butylcarbazole ligands bridging Cu ions, forming a framework with square-like pores.  The ligand butyl groups point into the pores, making them hydrophobic.   The adsorption of VOCs classified as chlorocarbons (e.g. CH2Cl2) and aromatic solvents such as benzene and toluene were shown to be fully reversible under ambient conditions.

Tests on the selectivity towards chlorocarbons showed that CHCl3 was adsorbed in preference to CH2Cl2 from a mixture.  This suggests that, unusually, selectivity may be based on the polarity of the molecules rather than the size – CHCl3 is larger but less polar than CH2Cl2.

In the case of the aromatic molecules, it proved possible to separate benzene and toluene from mixtures of toluene/ethylbenzene/xylene and ethylbenzene/xylene, respectively.   In both these systems, the larger molecules are adsorbed in preference to the smaller (benzene or toluene, respectively) – see diagram below.

Selective and reversible solvent separation by a MOF

Rather than being determined by the size or polarity of the solvent molecules, this can be explained if the hydrophobic properties are considered.  More hydrophobic molecules, such as ethylbenzene, are preferentially adsorbed into the hydrophobic pores present in the MOF, where they form favourable hydrophobic interactions.

The MOF reported here adds to the range available that show specific properties with regards to adsorption and separation of VOCs, unusually demonstrating specificity related to both the polarities and hydrophobicity of the VOCs.

For more information read the full paper at:

Reversible adsorption and separation of chlorocarbons and BTEX based on Cu(II)-metal organic framework
Fan Yang, Qi-Kui Liu, Jian-Ping Ma, Yan-An Li, Ke-Xin Wang and Yu-Bin Dong
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00547G
__________________________________________________________________________________________________
Gwenda KydGwenda 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. She has recently published a book on chemicals from plants.
Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

HOT articles

Take a look at the below HOT articles for the month of May and remember that these are only free to access for 4 weeks. The HOT article have been compiled into a collection and are available for viewing on our website.

Regiospecific growth of Au on a concave PtZn nanocube forming an Au–PtZn surface mosaic nanocube and an Au–PtZn octapod
Ki Woong Lee, Hyohyun An, Seungjoo Haam, Hionsuck Baik and Kwangyeol Lee
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00429B

Graphical Abstract

Free to access until 16th June 2015


In situ total X-ray scattering study of the formation mechanism and structural defects in anatase TiO2 nanoparticles under hydrothermal conditions
Jian-Li Mi, Kirsten M. Ø. Jensen, Christoffer Tyrsted, Martin Bremholm and Bo B. Iversen
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00544B

Graphical Abstract

Free to access until 16th June 2015


Tracking the transformations of mesoporous microspheres of calcium silicate hydrate at the nanoscale upon ibuprofen release: a XANES and STXM study
Xiaoxuan Guo, Zhiqiang Wang, Jin Wu, Yongfeng Hu, Jian Wang, Ying-Jie Zhu and Tsun-Kong Sham
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00500K

Graphical Abstract

 

Free to access until 16th June 2015


Blue light production by type-I non-critical phase matching second-harmonic generation in La(Ca1−xSrx)4O(BO3)3 single crystals
Alexandru Achim, Lucian Gheorghe, Flavius Voicu and George Stanciu
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00125K

Graphical Abstract

Free to access until 16th June 2015


High quality β-FeOOH nanostructures constructed by a biomolecule-assisted hydrothermal approach and their pH-responsive drug delivery behaviors
Xinyu Zhang, Juan Ge, Bo Lei, Yumeng Xue and Yaping Du
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00559K

Graphical Abstract

Free to access until 16th June 2015


Recent advances in the construction of lanthanide–copper heterometallic metal–organic frameworks
Shaowei Zhang and Peng Cheng
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00237K

Graphical Abstract

Free to access until 16th June 2015


Isotopomeric polymorphism in a “doubly-polymorphic” multi-component molecular crystal
Marc Schmidtmann, Derek S. Middlemiss and Chick C. Wilson
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00123D

Graphical Abstract

Free to access until 25th May 2015


Static and lattice vibrational energy differences between polymorphs
Jonas Nyman and Graeme M. Day
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00045A

Graphical Abstract

 Free to access until 25th May 2015


Structural insights into the hexamorphic system of an isoniazid derivative
D. Hean, T. Gelbrich, U. J. Griesser, J. P. Michael and A. Lemmerer
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00275C

Graphical Abstract

Free to access until 25th May 2015


Three anhydrous forms and a dihydrate form of quifenadine hydrochloride: a structural study of the thermodynamic stability and dehydration mechanism
Artis Kons, Ligita Rutkovska, Agris Bērziņš, Raitis Bobrovsa and Andris Actiņš
CrystEngComm, 2015,17, 3627-3635
DOI: 10.1039/C5CE00426H

Graphical Abstract
Free to access until 25th May 2015
Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

2nd ICSU/IUPAC Workshop on Crystal Engineering

The 2nd ICSU/IUPAC Workshop on Crystal Engineering will be held in Como, Italy on August 30-September 1, 2015.

The Chairmen of the Workshop, Pierangelo Metrangolo and Giuseppe Resnati, invite you to participate in this memorable event.

2nd ICSU/IUPAC Workshop on Crystal EngineeringThis international workshop will also serve as the mid-term meeting of the ICSU project CONvINCE “CONcepts and termINology in Crystal Engineering” and of the IUPAC project no. 2012-044-1-100 “Basic Terminology of Crystal Engineering”. The objectives of these projects are to produce guidelines for terminology in the area of crystal engineering.

The program of the workshop will comprise invited lectures by internationally renowned leaders in the field. Poster presentations are also scheduled and opportunities are planned for young scientists’ networking with both peers and recognized leaders in the field.

Participation is free and limited to a maximum number of 150 attendees, which will be selected on a first come first served basis.

The deadline for registration and abstract submission is June 30, 2015.

Full details of the Workshop can be found here.
For more information, please contact the:
Scientific Secretariat: johanna.syvanen@polimi.it or the Organizing Secretariat: chiara.stefanetti@centrovolta.it

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Porous materials with tunable hourglass-shaped channels

In a recent paper, Langford et al report the formation of three new molecular porous materials with tunable channels.  Tunability of the size and shape of the channels is important in the design of materials for gas sensing, guest exchange, catalysis and drug delivery.  Other important factors such as thermal and solvent stabilities are also good.

The new compounds are readily prepared from tin(IV) porphyrin phenolates. Their structures feature a one-dimensional hourglass-shaped channel lined with methyl groups.  The nature of the channel is readily varied by changing the methyl substitution of the phenolate component.  In this way, the pore radius can be varied from 3.1 Å to 4.5 Å (see diagram below, showing the three compounds down the crystallographic c axis with channels shown as orange spheres and phenolic methyl groups lining the channel shown in purple).

tin(iv)porphyrin phenolate materials

The compounds are robust compared to other molecular porous materials, thought to be due to a combination of stabilisation by hydrogen bonding and stacking of the aromatic groups.  In combination with the tunability, this suggests potential use for guest exchange or in small molecule capture applications and further investigation of this is ongoing.

For more information see the full paper at:

Supramolecular materials with robust and tunable channels constructed from tin(IV)porphyrin phenolates
Shuang Wang, Craig Forsyth and Steven J. Langford
CrystEngComm, 2015,17, 3060-3063

________________________________________________________________________________________________

Gwenda KydGwenda 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. She has recently published a book on chemicals from plants.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

IUPAC project meeting and workshop: Topology representations in coordination networks, MOFs and other crystalline materials

Posted on behalf of Lars Öhrström (CrystEngComm Advisory Board)

A follow up to the IUPAC project on the somewhat controversial issue on terminology of metal-organic frameworks and coordination polymers deals with the question of how we describe and communicate the structures of MOFs, PCPs and related network forming compounds.

The use of topology is very efficient in describing, disseminating and even designing such new materials, and the IUPAC task group deals with the project: Terminology guidelines and database issues for topology representations in coordination networks, metal-organic frameworks and other crystalline materials. As it turns out, network topology is also important, albeit sadly neglected, for the group 14 allotropes and even polymorphs of water.

The task group invite all who are interested to a workshop in Samara, Russia 21-23 May 2015 under the devise ”Describe, Disseminate and Design”. The workshop will feature talks by prominent scientist highlighting the network topology approach from many different angles, from mathematics to chemical synthesis and will also help the task group to gather viewpoints from the community. There will also be a poster session.

You can register and submit an abstract until 30th April 2015.

If you are interested but can’t make it, why not send thoughts directly to the project chair, Lars Öhrström or on twitter @larsohrstrom #IUPACmof2

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

March’s HOT articles

Take a look at March’s HOT articles below and remember that these are only free to access for 4 weeks. The HOT article have been compiled into a collection and are available for viewing on our website.

Understanding the packing in the 1:1 molecular complex 1,3,5-tricyanobenzene–hexamethylbenzene by probing lattice modes
John A. Stride
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00328H

Graphical Abstract

Free to access until 23rd April 2015


Influence of oxygen partial pressure on SrTiO3 bulk crystal growth from non-stoichiometric melts
Christo Guguschev, Dirk J. Kok, Zbigniew Galazka, Detlef Klimm, Reinhard Uecker, Rainer Bertram, Martin Naumann, Uta Juda, Albert Kwasniewski and Matthias Bickermann
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00095E

Graphical Abstract

Free to access until 14th April 2015


Crystallization and disorder of the polytypic α1 and α2 polymorphs of piroxicam
Pratik P. Upadhyay and Andrew D. Bond
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00050E

Graphical Abstract

Free to access until 14th April 2015

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

A new MOF for sensitive nitrobenzene sensing

Nitrobenzene is an important industrial material used in the production of aniline, dyes, pharmaceuticals and explosives.  However, it is highly toxic, considered likely to be a human carcinogen and does not readily degrade so accurate sensing of nitrobenzene in the environment, even at very low concentrations, is required.

A new paper presents a Cd-based metal-organic framework (MOF) as a highly selective and efficient sensor of nitrobenzene.  The MOF is based on a new flexible ligand with aromatic character, chosen to complement nitrobenzene’s electron withdrawing character.  The ligand, 1,1-(1,4-phenylenebis(methylene))bis(1H-pyrazole-3,5-dicarboxylicacid) and a source of Cd react under hydrothermal conditions to form the new Cd-MOF.

This shows a fluorescence emission when excited at 297 nm which is quenched by the presence of nitrobenzene (see diagram below).

Nitrobenzene sensing using a cadmium organic framework

The suggested mechanism of quenching involves photoinduced electron transfer. Quenching is inversely related to the concentration of nitrobenzene and significant quenching occurs at concentrations as low as 50 ppm nitrobenzene. Thus, Cd-MOF is suggested as a sensitive, rapid probe for low concentrations of nitrobenzene.

For the full paper see:

A new Cd(II)-based metal–organic framework for highly sensitive fluorescence sensing of nitrobenzene

Yu-Pei Xia, Yun-Wu Li, Da-Cheng Li, Qing-Xia Yao, Yu-Chang Du and Jian-Min Dou

CrystEngComm, 2015, Advance Article
DOI: 10.1039/C5CE00162E

__________________________________________________________________________________________________

Gwenda Kyd

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. She has recently published a book on chemicals from plants.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

February’s HOT articles

Take a look at February’s HOT articles below and remember that these are only free to access for 4 weeks! The HOT article have been compiled into a collection and are available for viewing on our website.

New, intermediate polymorph of CeAlO3 with hexagonal structure – formation and thermal stability
Małgorzata A. Małecka and Leszek Kępiński
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C4CE02201G 

Graphical Abstract

Free to access until 25th March 2015


Template-free synthesis of mesoporous anatase titania hollow spheres and their enhanced photocatalysis
Changchao Jia, Ping Yang, Hsueh-Shih Chen and Junpeng Wang
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C4CE02358G

Graphical Abstract

Free to access until 25th March 2015


Fabrication of arrays of high-aspect-ratio diamond nanoneedles via maskless ECR-assisted microwave plasma etching
Yang Yang, Muk-Fung Yuen, Xianfeng Chen, Shanshan Xu, Yongbing Tang and Wenjun Zhang
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C4CE02267J

Graphical Abstract

Free to access until 9th March 2015


Rapid crystal growth of type-II clathrates A8Na16Si136 (A = K, Rb, Cs) by spark plasma sintering
Yongkwan Dong and George S. Nolas
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C4CE02221A

Graphical Abstract

Free to access until 9th March 2015


Tunability of guest release properties and crystal structures in a supramolecular benzothiophene heterocyclic host complex
Takashi Wakabayashi, Sayaka Kitamura, Hideyuki Tabata, Reiko Kuroda and Yoshitane Imai
CrystEngComm, 2015, Advance Article
DOI: 10.1039/C4CE02496F

Graphical Abstract

Free to access until 9th March 2015

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Foiled again! One-pot hydrothermal route to freestanding copper foil

Posted on behalf of Rachel Coulter, web writer for CrystEngComm

The physical form of a compound affects its properties – one need only look at the explosion of research about nanosized materials in recent years to see the dramatic effects that size and shape can have on behaviour. Metal foams and foils with nanoporous structure have large surface-to-volume ratios, which make them valuable in a range of applications. Recently, Ming Li and colleagues, based in Shanghai, have developed a simple one-pot hydrothermal route to nanoporous copper foils that self-assemble in relatively short reaction times.

The mild hydrothermal route uses readily available starting materials, and ethylene glycol is employed as a reducing agent in the reaction. After 6 hours at 200°C the blue emulsion is transformed to a copper foil, which detaches itself from the Teflon wall of the autoclave liner.

The foil is thoroughly characterised and has a uniform thickness of approximately 1.4 microns, as seen in the SEM image below. A nanoporous structure can also be seen, accounted for by a mechanism of initial formation of Cu branches, which join together to form the foil as the reaction progresses. A thin coating of copper oxide on the surface makes the foils stable in air.

The as-synthesised copper foil and a close-up SEM image are shown below.

Copper foil

All so far so interesting, but what can such films be used for? The visible absorbance is higher than that of commercially available copper films owing to the nanostructure present. This means it can be used as an active substrate for surface enhanced Raman scattering (SERS). These substrates need to absorb light via surface plasmon resonance, an effect commonly seen in coinage metals. However, gold and silver have been found to be too expensive and too unstable, respectively, so cooper provides a high-performing low cost alternative.

Other potential applications include use as electrodes in batteries, solar cells or displays, and the authors hope that the method is applicable for the creation of other metal foils.

Find the full article here:

One-pot preparation of thin nanoporous copper foils with enhanced light absorption and SERS properties
Ming Li, Yanjie Su, Jiang Zhao, Huijuan Geng, Jing Zhang, Liling Zhang, Chao Yang and Yafei Zhang
CrystEngComm, 2015, 17, 1296-1304
DOI: 10.1039/C4CE01967A


Rachel Coulter is currently working on a PhD at the University of Liverpool, investigating near-infrared absorbing materials. Her interests include solvothermal synthesis, optical applications of inorganic compounds and synthesis of nanoparticles. She received an MChem from the University of Edinburgh in 2011, which included an Erasmus year in Lille, France.
Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Shape-changing microcrystals by tumble mixing

Some crystals can deform on exposure to UV or visible light as a photoreaction proceeds during which the reactant and product are both present. This causes internal strain, which can result in crystals bending, jumping or twisting. For a well-defined response to occur, control of crystal size and shape are vital. Micron-sized crystals (microcrystals) are more likely to exhibit the desired behaviour, as larger crystals may shatter owing to the internal stresses produced.

A new paper outlines a method for producing uniform microcrystals. This is demonstrated by the synthesis of (E)-3-(anthracen-9-yl)acrylic acid (9-AYAA) from its t-butyl ester analogue by tumble mixing with phosphoric acid and a surfactant (sodium dodecyl sulfate, SDS). The size and shape can be controlled by the reaction temperature, concentration of phosphoric acid and SDS, the ester concentration and the mixing method. The optimised reaction conditions produce uniform 9-AYAA microwires, which undergo coiling (during the photoreaction) and uncoiling (as the reaction reaches completion) on exposure to 475 nm light, as shown in the figure below.

Shape-changing organic crystals by tumble mixing

The new method involves an in-situ chemical reaction (acid hydrolysis) followed by re-precipitation and can also be successfully used to produce 9-AA (9-anthraldehyde) microplates under similar conditions. The authors attribute the success of their syntheses to the slow growth of the products and conclude the strategy could be used to produce microcrystals of uniform size and shape in other systems.

For more details, see the full paper at:

Chemical reaction method for growing photomechanical organic microcrystals
Rabih O. Al-Kaysi, Lingyan Zhu, Maram Al-Haidar, Muhannah K. Al-Muhannah, Kheireddine El-Boubbou, Tarafah M. Hamdan and Christopher J. Bardeen
CrystEngComm, 2015, DOI: 10.1039/C4CE02387K


Gwenda Kyd 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. She has recently published a book on chemicals from plants.
Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)