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Author Archive

Quantitative analysis of solvent effects on molecular recognition

16 Apr 2013

Scientists in the UK are attempting to understand the host–guest chemistry of molecular cages in solution, by separately quantifying the free energy contributions of (at least) three host–guest interaction mechanisms that usually work in unison: hydrogen-bonding, non-polar interactions and solvophobic effects.

The team have systematically looked at a series of guests (with/without π-stacking ability and different hydrogen-bond acceptor capabilities), within a water-soluble cubic coordination cage and an isostructural organic-soluble cage.

Being able to quantify solvent effects associated with specific molecular substituents or functional groups will help in the design of hydrophobic cavities within coordination cages. Hydrophobic cavities can stabilise otherwise unstable molecular guests and catalyse reactions where the transition state matches the cavity size and shape.

Read this ‘HOT’ article, hot off the press:

Quantification of solvent effects on molecular recognition in polyhedral coordination cage hosts
Martina Whitehead , Simon Turega , Andrew Stephenson , Chris Hunter and Mike D Ward
Chem. Sci., 2013, Accepted Manuscript
DOI: 10.1039/C3SC50546D

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Squaraine rotaxane shuttle as a ratiometric deep-red optical chloride sensor

15 Apr 2013

Chloride ions are central to many biological processes and measuring the concentration of chloride ions in biological fluids can help diagnose a number of diseases, including cystic fibrosis.

Scientists from the US have synthesised a squaraine rotaxane which can detect chloride ions via colorimetric naked eye detection and fluorescence. This is the first example of a ratiometric chloride sensor that emits in the deep red region.

Read the ‘HOT’ Chemical Science article for free:

Squaraine rotaxane shuttle as a ratiometric deep-red optical chloride sensor
Carleton G. Collins, Evan M. Peck, Patrick J. Kramer and Bradley D. Smith
Chem. Sci., 2013, DOI: 10.1039/C3SC50535A

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MOF that can extract uranium from water

08 Apr 2013

Scientists in the US have prepared three UiO-68 network topology metal-organic frameworks (MOFs) using phosphorylurea substituted organic ligands and used them as sorbents to extract actinide elements from water and artificial sea water.

The MOFs were shown to be highly efficient at sorbing uranyl ions, with saturation sorption capacities as high as 217 mg U g^-1 which is equivalent to binding one uranyl ion for every two sorbent groups.

In the future, the technology could be used to extract uranium from seawater for nuclear fuel production and for the removal of radionuclides from waste streams and drains at nuclear power plants.

Read this ‘HOT’ article for free for a limited period:

Highly porous and stable metal-organic frameworks for uranium extraction
Wenbin Lin , Michael Carboni , Carter Abney and Shubin Liu
Chem. Sci., 2013, DOI: 10.1039/C3SC50230A

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DNA-based asymmetric organometallic catalysis in water

28 Mar 2013

Scientists studying organometallic catalysts attached to DNA have used the technology to perform cyclopropanation reactions in water, and have reported efficient yields and high enantiomeric excesses.

By attaching the catalytically active metal complex to a DNA scaffold, the chirality of the DNA helix can be directed toward the reaction, influencing its outcome.

You can read this article for free for a limited period:

DNA-based asymmetric organometallic catalysis in water
Jens Oelerich and Gerard Roelfes
Chem. Sci., 2013, DOI: 10.1039/C3SC00100H

DNA

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Nanotechnology: The role of ink viscosity in dip-pen lithography

26 Mar 2013

Chad Mirkin and colleagues have investigated how the flow of block co-polymer inks from the tip of an AFM probe is affected by the ink’s viscosity. The size of the ink features was found to increase with dwell time and decrease with ink viscosity.

The technique, known as dip-pen nanolithography, was originally developed as a molecular patterning technique for printing small alkanethiol molecules onto a gold surface, but it has rapidly become popular method for synthesising all manner of nano structures.

An understanding of how different substances behave as they move between the probe tip and the surface of the substrate is crucial for designing new materials, patterns and processes.

Read the article for free today:

The role of viscosity on polymer ink transport in dip-pen nanolithography
Guoliang Liu , Yu Zhou , Resham S. Banga , Radha Boya , Keith A. Brown , Anthony J. Chipre , SonBinh T. Nguyen and Chad A. Mirkin
Chem. Sci., 2013, DOI: 10.1039/C3SC50423A

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Mechanism of water splitting on gold surfaces

25 Mar 2013

A comprehensive study of the mechanism by which electrochemical water splitting occurs on gold surfaces has been carried out by scientists writing in Chemical Science.

The researchers used in-situ surface enhanced Raman spectroscopy (SERS), on-line electrochemical mass spectrometry and density functional theory (DFT) calculations and found that more than one mechanism may be at work, depending on the voltage applied.

The results show that electrocatalytic surfaces for oxygen evolution may undergo dynamic changes as the reaction progresses. The oxygen evolved on a gold electrode at the onset of potential appears to be the product of an oxygen decomposition step.

Electrochemical water splitting by gold: evidence for an oxide decomposition mechanism
Marc T.M. Koper , Oscar Diaz-Morales , Federico Calle-Vallejo and Casper de Munck
Chem. Sci., 2013, DOI: 10.1039/C3SC50301A

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Last chance to speak at Challenges in Chemical Biology (ISACS11)

14 Mar 2013

This is your last chance to submit an oral abstract for Challenges in Chemical Biology (ISACS11) which will be held on 23-26 July in Boston, USA.

Submit before the deadline of Friday 15 March 2013 to take advantage of this exceptional opportunity to showcase your work alongside researchers from across the globe.

For details of speakers and conferences themes, please visit the dedicated website.

Confirmed invited speakers include:

Professor Ben Cravatt
The Scripps Research Institute, USA
Professor Carl Figdor
Radboud University Nijmegen, The Netherlands
Professor Susan Lindquist
Whitehead Institute for Biomedical Research, USA
Professor Tom Muir
Princeton University, USA
Professor Udo Oppermann
University of Oxford, UK
Professor Hidde Ploegh
Massachusetts Institute of Technology (MIT), USA
Professor Alanna Schepartz
Yale University, USA
Professor Stuart Schreiber
Broad Institute and Harvard University, USA
Professor Dirk Trauner
Ludwig-Maximilians-Universität (LMU), Germany
Professor Ada Yonath HonFRSC
Weizmann Institute, Israel

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Challenges in Chemical Biology (ISACS11) – Oral Abstract Deadline 15 March

06 Mar 2013

This is your last chance to submit an oral abstract for Challenges in Chemical Biology (ISACS11) which will be held on 23-26 July in Boston, USA.

Act before the deadline of Friday 15 March 2013 to take advantage of this exceptional opportunity to showcase your work alongside researchers from across the globe.

For details of speakers and conferences themes, please visit the dedicated website.

Confirmed invited speakers include:

Professor Ben Cravatt
The Scripps Research Institute, USA
Professor Carl Figdor
Radboud University Nijmegen, The Netherlands
Professor Susan Lindquist
Whitehead Institute for Biomedical Research, USA
Professor Tom Muir
Princeton University, USA
Professor Udo Oppermann
University of Oxford, UK
Professor Hidde Ploegh
Massachusetts Institute of Technology (MIT), USA
Professor Alanna Schepartz
Yale University, USA
Professor Stuart Schreiber
Broad Institute and Harvard University, USA
Professor Dirk Trauner
Ludwig-Maximilians-Universität (LMU), Germany
Professor Ada Yonath HonFRSC
Weizmann Institute, Israel

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Nanoscience: Porous iron(III) nanoparticles show no signs of in vivo toxicity in rats

28 Jan 2013

The in vivo toxicity of iron nanoparticles in rats has been tested by a group of French and Tunisian scientists, who found that the compounds are not metabolised by the animals and cause no toxic effects.

The group tested three different porous iron(III) metal-organic framework (MOF) nanoparticles, injecting them intravenously and studying their distribution, metabolism and excretion. The nanoparticles are rapidly sequestered by the liver and spleen and, after biodegradation, are directly excreted from the body through urine or faeces without metabolisation, substantial toxicity or affecting organ function.

There is currently much concern and debate over the safety and toxicity of nanoparticles, especially with regard to human health. This study shows that biodegradable non-toxic iron(III) carboxylate MOF nanoparticles could have real potential for future biomedical applications.

Read the ‘HOT’ Chemical Science article in full:

In depth analysis of the in vivo toxicity of nanoparticles of porous iron(III) metal-organic frameworks
Tarek Baati , Leila Njim , Fadoua Neffati , Abdelhamid Kerkeni , Muriel Bouttemi , Ruxandra Gref , Mohamed F Najjar , Abdelfateh Zakhama , Patrick Couvreur , Christian Serre and Patricia Horcajada
Chem. Sci., 2013, DOI: 10.1039/C3SC22116D

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New insights into f-element bonding trends

10 Jan 2013

Scientists in the US have reported a new insight into the understanding of the bonding trends within, and the differences between, the 4f and 5f element series with soft donor atom ligands.

The coordination chemistry and differing bond lengths explain the covalency of different 4f and 5f elements, they say. The team studied a series of actinide versus lanthanide complexes.

This work is useful for the design and optimisation of actinide separation schemes (for nuclear fuel).

Read the Chemical Science article for free today:

Uncovering f-Element Bonding Differences and Electronic Structure in a Series of 1:3 and 1:4 Complexes with a Diselenophosphinate Ligand
M B Jones et al, Chem. Sci., 2012, DOI: 10.1039/c2sc21806b

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