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Archive for the ‘Materials’ Category

New micro-dendrites separate themselves from the field

20 May 2011

Bioanalysis and biosensors represent a current area of wide interest in the chemical sciences. Much work is being put into methods that allow easy separation and detection of biological targets. Erkang Wang and coworkers at the Chinese Academy of Sciences in Changchun have presented a new way of doing just that.

The group synthesised a new type of silver micro-dendrite (SMD) that has a silver surface perfect for tethering biomolecules. The SMDs could also be reversibly separated and dispersed in water merely by oscillation and then settling under gravity for 30 seconds.

The team used the SMDs to successfully detect DNA from sickle cell disease, human T-lymphotropic virus and anthrax. Probe DNA was attached to the SMDs and then the target strands were selectively bound with a second, fluorophore-containing probe. The target DNA could then be detected using laser scanning confocal microscopy. They found that this technique was so sensitive it could even detect DNA with a one nucleotide mismatch.

Wang hopes that this type of separation system can be expanded to more targets and other types of sensing system.

Interested in finding out more? Then download the ChemComm article for free today and leave a comment below.

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The first use of organometallic hosts in crystalline organic frameworks

16 May 2011

Chemists working at Ruhr-University Bochum in Germany have for the first time studied the host–guest chemistry of organometallic complexes with covalent organic frameworks (COVs).

COVs are the organic analogues of metal–organic frameworks (MOFs) and are made up of strong organic covalent bonds to form large organic polymers. They have a crystalline structure and have attracted a lot of attention due to their possible applications in gas storage, sensing and catalysis. To date, only the host–guest chemistry of small gas molecules such as CO₂ and H₂ have been studied in COVs. The team in Germany, led by Roland A. Fischer, set about changing this and demonstrated the use of organometallic molecules as guests.

Using COF-102 as the host, the team looked at the adsorption of FeCp₂, CoCp₂and [Ru(cod)(cot)] within the framework. They found that FeCp₂ remained intact within the framework and that it assumed a structure reminscent of the host via π–π interactions. Overall, the work displayed the similarity between COVs and MOFS as hosts for metal complexes.

If you are interested in finding out more on this hot area then why not download the full ChemComm article for free today?

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Call for communications: Artificial Photosynthesis

06 May 2011

We are delighted to announce a forthcoming web themed issue:

Artificial Photosynthesis

Guest editor: Andrew Benniston (Newcastle University)

Submission deadline: 15th August 2011 EXTENDED TO 30TH SEPTEMBER!!

We are now welcoming submissions for this web theme, which will be a celebration of current achievements and future perspectives in this exciting field of research. Communications covering all aspects of the following areas are encouraged:

new materials and photocatalysts for solar photochemistry
hydrogen production and water splitting
nitrogen and carbon dioxide functionalisation
light harvesting and energy transfer
electron transfer (tunnelling vs hopping)
coupled proton/electron transfer
long-range electron transport
multi-electron redox processes
bioinspired molecular systems
nanostructures for solar energy usage

All manuscripts will undergo strict peer review and should be very important and conceptually significant in accord with the ChemComm mandate.

Publication of the peer-reviewed articles will occur without delay to ensure the timely dissemination of the work. The articles will then be assembled on the ChemComm website as a web-based thematic issue, to permit readers to consult and download individual contributions from the entire series.

Communications for this web theme can be submitted anytime from now until 30th September using our web submission system. Please add the phrase ‘artifical photosynthesis’ in the comments to the editor field.

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Titanate cigarette filter

04 May 2011

Cigarette in a hand Chinese researchers have shown for the first time that nanomaterials made from titanium dioxide (TiO₂) can be used in cigarette filters to significantly reduce the amount of harmful chemicals inhaled by smokers. They say it offers a cheaper and safer alternative than using carbon-based nanomaterials and show potential for use in other filtering devices including gas masks and air purification systems.

Current cigarette filters are made from cellulose acetate, which absorbs some of the toxic and carcinogenic compounds present in tobacco smoke, including tar, nicotine, polycyclic aromatic hydrocarbons and tobacco-specific nitrosamines. In recent years, scientists have attempted to improve standard filters by adding nanomaterials, including carbon nanotubes or mesoporous silica, to capture more of these chemicals. But these experimental methods remain expensive and could pose unknown health risks.

Now, Mingdeng Wei’s lab at Fuzhou University in Fujian province, together with colleagues at the Fujian Tobacco Industrial Corporation, Xiamen, have found that titanate nanosheets and nanotubes can filter tobacco smoke. ‘A great range of harmful compounds including tar, nicotine, ammonia, hydrogen cyanide, selected carbonyls and phenolic compounds can be reduced efficiently,’ says Wei.

Intrigued? Read the full news story in Chemistry World and download the ChemComm communication.

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A new and simple polymer synthesis for polymer solar cells

12 Apr 2011

A team of Swedish chemists have presented a novel and straightforward method for synthesising polymers for use in polymer solar cells (PSC) with a wide absorption spectrum.

The researchers, led by Mats R. Andersson from the Chalmers University of Technology in Sweden, synthesised the polymer from a widely available stannyl thiophene and an easily synthesised bromoisoindigo monomer. These were then coupled together using a Stille coupling reaction. Overall this represents just 3 steps and was achieved with a high overall yield of 68%.

The polymer itself is a low band-gap polymer with a donor–acceptor structure, which is important for harvesting photons from sunlight. The team found that the polymer exhibited promising performance when used in a PSC device and expect to be able to further improve this by varying the indigo groups.

If you would like to read more about this topic then download the ChemComm article for free today. Also, why not check out these other great ChemComm articles on PCSs?

Synthesis of annulated thiophene perylene bisimide analogues: their applications to bulk heterojunction organic solar cells
Hyunbong Choi, Sanghyun Paek, Juman Song, Chulwoo Kim, Nara Cho and Jaejung Ko
Chem. Commun., 2011, DOI: 10.1039/C0CC05448H

Crystalline conjugated polymer containing fused 2,5-di(thiophen-2-yl)thieno[2,3-b]thiophene and thieno[3,4-c]pyrrole-4,6-dione units for bulk heterojunction solar cells
Guan-Yu Chen, Yu-Hsin Cheng, Yi-Jen Chou, Ming-Shin Su, Chia-Min Chen and Kung-Hwa Wei
Chem. Commun., 2011, DOI: 10.1039/C1CC10585J

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A supramolecular approach to zwitterionic metal silanides

31 Mar 2011

Zwitterionic metal silanides represent a structurally novel class of tri-coordinated silyl anions in which the cationic metal centre is separated from the silicon anion by internal donor bridges.

Clemens Krempner and co-workers have now reported that key to the synthesis of stable, isolable species is the use of pendant polydonor groups that exclusively bind to the metal cation and serve to prevent self-aggregation.

Due to the shape of these unusual compounds, the electron pair located at the central silicon anion is available for additional metal binding. This has allowed for the synthesis of hitherto unknown zwitterionic heterobimetallic silanides, by reaction of the zwitterionic metal silanides with boron, aluminium or tungsten-containing species.

To read about these intriguing compounds in more detail, download the ChemComm communication, which is available for free until April 28th.

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A Sustainable Global Society: How Can Materials Chemistry Help?

31 Mar 2011

A high profile white paper A Sustainable Global Society: How Can Materials Chemistry Help? was launched internationally on 27 March.

The output of the Chemical Sciences and Society Summit (CS3) 2010, which took place in London, September 2010, outlines five key areas in which materials chemists, through collaboration with other scientists, industry and policy makers, can seize exciting opportunities to address global challenges. This project was driven by the RSC and is a collaboration between the chemical societies of China, Germany, Japan, the US, the UK and national funding bodies. Around 30 leading materials chemists from the participating nations participated in CS3 2010 and the white paper is a reflection of the outcome of the summit, in particular their view of the future direction for materials chemistry.

View the official website of the white paper.

Read the 27 March press release.

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New tool for speeding up porous materials discovery

28 Mar 2011

A new tool (Infrasorb-12) for screening porosity has been developed by scientists in Germany. The tool identifies high surface area materials in a very short time with high accuracy. The researchers say that Infrasorb-12 development will speed up the discovery of new porous materials significantly and broaden the wide range of materials suitable for gas storage, selective adsorption, catalysis, and life science applications.

Further information:
High-throughput screening: speeding up porous materials discovery
Philipp Wollmann, Matthias Leistner, Ulrich Stoeck, Ronny Grünker, Kristina Gedrich, Nicole Klein, Oliver Throl, Wulf Grählert, Irena Senkovska, Frieder Dreisbach and Stefan Kaskel, Chem. Commun., 2011, DOI: 10.1039/C1CC10674K

Also of interest:
Modifying MOFs: new chemistry, new materials
Seth M. Cohen, Chem. Sci., 2010, 1, 32-36 (DOI: 10.1039/C0SC00127A)

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Carbon dioxide adsorption in porous phosphine coordination material

28 Mar 2011

US, UK and Korean scientists have made a new porous phosphine coordination material, PCM-11. The material is an unusual 8,4-connected coordination polymer with an open 3-D pore structure, say the researchers.

The team formed the material by reacting Mg(II) with tris(para-carboxylato)triphenylphosphine oxide. The highly ionic nature of the metal–ligand bonding results in excellent thermal stability upon desolvation (>460 ºC), they say. PCM-11 is easily activated for small molecule sorption at low temperature without the requirement for solvent pre-exchange. It adsorbs 47.5 wt% CO₂ at 11.6 bar and 30ºC.

Find out more in the ChemComm communication:
High capacity CO₂ adsorption in a Mg(II)-based phosphine oxide coordination material
Alisha M. Bohnsack, Ilich A. Ibarra, Peter W. Hatfield, Ji Woong Yoon, Young Kyu Hwang, Jong-San Chang and Simon M. Humphrey, Chem. Commun., 2011, DOI: 10.1039/C1CC10754B

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A new class of molecular propellers

28 Feb 2011

Scientist based in Italy have recently demonstrated a new class of molecular propellers based upon polyoxometalates (POMs).

POMs consist of a cluster of transition metal oxides that are water soluble and are used for a wide range of applications. In particular, Andrea Sartorel and Marcella Bonchio, from the Univerity of Padova, are interested in their use as photosynthetic oxygen-evolving catalysts. The team studied a series of POMs with different metal centres and their catalytic performance in the disproportionation of hydrogen peroxide (H₂O₂) to water and oxygen.

They found that of all the POMS studied, Ru₄(SiW₁₀)₂ performed the best in terms of oxygen evolution. This production of oxygen could then be used to create movement of the POM; in effect using H₂O₂as fuel to create oxygen that then propels the POM material in aqueous solution. A video of this can be seen here. This represents a step towards the use of light-driven molecular machines based on POMs.

If you are interested in finding out more, then why not download Sartorel and Bonchio’s ChemComm article for free today? Also, don’t forget to leave a comment below!

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