Chemical Science Blog

Hydrogen is explosive – it’s one of the first things children learn in their chemistry classes.

This is a serious drawback for the catalytic hydrogenation of multiple bonds, one of the most widely used reactions in organic synthesis. But now Steven Ley and colleagues at the University of Cambridge, UK, have improved the safety profile of both homogeneous and heterogeneous catalytic hydrogenations using flow chemistry.

In their Chemical Science Edge article, the group describe their ‘Tube-in-Tube’ reactor/injector and a novel computer-assisted bubble counting technique to measure the levels of hydrogen uptake.

Read the article for free and leave your comments below. If you’d like to be seen with the best, submit to Chemical Science today.

Also of interest:
Ten key issues in modern flow chemistry – a ChemComm Highlight in Chemistry article by Andreas Kirschning and colleagues

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.

This month sees the following articles in Chemical Science that are in the top ten most accessed:-

Why not take a look at the articles today and blog your thoughts and comments below.

A synthesis of strychnine by a longest linear sequence of six steps 
David B. C. Martin and Christopher D. Vanderwal 
Chem. Sci., 2011, 2, 649-651, DOI: 10.1039/C1SC00009H, Edge Article 

Transition metal-catalyzed cross coupling with N-acyliminium ions derived from quinolines and isoquinolines 
Thomas J. A. Graham, Jason D. Shields and Abigail G. Doyle 
Chem. Sci., 2011, Advance Article, DOI: 10.1039/C1SC00026H, Edge Article 

Dialkylbiaryl phosphines in Pd-catalyzed amination: a user’s guide 
David S. Surry and Stephen L. Buchwald 
Chem. Sci., 2011, 2, 27-50, DOI: 10.1039/C0SC00331J, Perspective 

Enantioselective silver-catalyzed propargylation of imines 
Hanna M. Wisniewska and Elizabeth R. Jarvo 
Chem. Sci., 2011, 2, 807-810, DOI: 10.1039/C0SC00613K, Edge Article 

Chemoselective enrichment for natural products discovery 
Antoinette Y. Odendaal, Darci J. Trader and Erin E. Carlson 
Chem. Sci., 2011, 2, 760-764, DOI: 10.1039/C0SC00620C, Edge Article 

Gold(i)-catalyzed intermolecular (4 + 2) cycloaddition of allenamides and acyclic dienes 
Hélio Faustino, Fernando López, Luis Castedo and José L. Mascareñas 
Chem. Sci., 2011, 2, 633-637, DOI: 10.1039/C0SC00630K, Edge Article 

Palladium-catalyzed coupling of functionalized primary and secondary amines with aryl and heteroaryl halides: two ligands suffice in most cases 
Debabrata Maiti, Brett P. Fors, Jaclyn L. Henderson, Yoshinori Nakamura and Stephen L. Buchwald 
Chem. Sci., 2011, 2, 57-68, DOI: 10.1039/C0SC00330A, Edge Article 

Total synthesis of diazonamide A 
Robert R. Knowles, Joseph Carpenter, Simon B. Blakey, Akio Kayano, Ian K. Mangion, Christopher J. Sinz and David W. C. MacMillan 
Chem. Sci., 2011, 2, 308-311, DOI: 10.1039/C0SC00577K, Edge Article 

Coordination chemistry of group 13 monohalides 
Dragoslav Vidovic and Simon Aldridge 
Chem. Sci., 2011, 2, 601-608, DOI: 10.1039/C0SC00508H, Minireview 

Stable singlet carbenes as mimics for transition metal centers 
David Martin, Michele Soleilhavoup and Guy Bertrand 
Chem. Sci., 2011, 2, 389-399, DOI: 10.1039/C0SC00388C, Perspective 

Fancy submitting an article to Chemical Science ? Then why not submit to us today or alternatively email us your suggestions.

US scientists have reported the preparation and synthetic applications of sulfinimines derived from benzoquinone monoketals. The method provides the first direct access to a variety of enantioenriched 4-aminocyclohexadienones, which possess synthetic handles for further elaboration to alkaloid natural products, say the researchers.

They demonstrated the the utility of the method in a short, enantioselective total synthesis of the natural product 3-demethoxyerythratidinone.

Read more:
Benzoquinone-derived sulfinyl imines as versatile intermediates for alkaloid synthesis: Total synthesis of (–)-3-demethoxyerythratidinone
K V Chuang, R Navarro and S E Reisman, Chem. Sci., 2011, DOI: 10.1039/c1sc00095k

UK scientists have come up with a new design rule for organic photovoltaics (OPVs), which could lead to improved solar cells.

Until recently, many of the polymers studied for OPVs had originally been developed for the more mature organic light emitting diode (OLED) and organic field effect transistor fields. For OLEDs, a high photoluminescence (PL) emission yield is a prerequisite, and this was also thought to be a positive indicator of a polymer’s OPV suitability.

But, by comparing the photophysics and photovoltaic performance of two different polymer–fullerene blends, James Durrant and colleagues have demonstrated that a high PL yield is not necessarily a positive attribute for polymers for OPV. OPV polymers should not, in general, exhibit strong photoluminescence which spectrally overlaps with fullerene absorption.

Read Energy versus electron transfer in organic solar cells: a comparison of the photophysics of two indenofluorene: fullerene blend films for free today to find out more.

A water molecule can act as a spy to sense and expose the reasons behind the anomeric effect in carbohydrates.

Since it was identified more than 50 years ago, the anomeric effect’s origins have been hotly debated. Scientists have found it difficult to separate stereoelectronic effects from other potential influences, including solvation.

Using vibrational spectroscopy, researchers have studied doubly hydrated anomers of a mannopyranoside under molecular beam conditions in the gas phase. By substituting heavy water (D₂O) for H₂O, they separated the carbohydrate (OH) bands from the water (OD) bands, helping them to interpret differences in the anomers’ vibrational signatures. One of the water molecules acted as a remarkably sensitive reporter, able to sense and expose subtle stereoelectronic changes through the resulting changes in its hydrogen-bonded interaction with the substrate.

Eager to read more? Download the full Edge article in Chemical Science for free:
Heavy water hydration of mannose: the anomeric effect in solvation, laid bare
Nitzan Mayorkas, Svemir Rudić, Benjamin G. Davis and John P. Simons, Chem. Sci., 2011, DOI: 10.1039/C1SC00002K

Scientists in Germany have developed a strategy to visualise oxygen concentrations in cells to better understand its role in biological reactions such as metabolism.

Hans Gorris from the University of Regensburg and colleagues have embedded two luminescent dyes within polystyrene particles, which were taken up by cells. One is a red light-emitting indicator dye that alters its luminescence depending on the oxygen concentration; the second is a green light-emitting dye that acts as a reference and is not sensitive to oxygen. The colours enabled the dyes to be monitored on the green and red channels in a red-green-blue (RGB) digital camera, together with a fluorescence microscope.

Schematic drawing of a ratiometric oxygen-sensitive polystyrene PEBBLE

See Chemistry World for the full news story  

Link to journal article
Self-referenced RGB colour imaging of intracellular oxygen
Xu-dong Wang, Hans H. Gorris, Judith A. Stolwijk, Robert J. Meier, Dominik B. M. Groegel, Joachim Wegener and Otto S. Wolfbeis
Chem. Sci., 2011, DOI: 10.1039/c0sc00610f