Chemical Science Blog

UK chemists have created a new class of container molecules that can incorporate different functional groups on their exterior surface, much like a cell displays different biomolecules on its surface.

Jonathan Nitschke and colleagues at the University of Cambridge used subcomponent self-assembly to make tetrahedral metal-organic capsules with twelve exchangeable aniline residues at the vertices of the cage. The modular construction allows their exteriors to be tailored to suit a given environment and reconfigured in response to external stimuli, explains Nitschke. The capsules bind guest species with great selectivity, he adds.

Nitschke talks about this study and his ideas for future work in the latest Chemical Science audio file, which accompanies his Edge article.

For more information about container molecules, read Nitschke’s Chemical Science Mini review and his ChemComm communication, part of the ChemComm Emerging Investigators issue.

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Photos reproduced with the permission of ACES XP

Nanoporous metal-organic frameworks (MOFs) loaded with silver can serve as templates for ordered nanostructures, say US scientists.

Mark Allendorf, at Sandia National Laboratories, Livermore, and colleagues impregnated a MOF with silver then exposed the MOF to an electron beam. The beam broke down the template, leading to silver coalescence and the formation of ordered silver nanostructures.

The method forms either silver nanoparticles or nanowires depending on the MOF’s structure and the extent of silver loading, explains Allendorf.

Although the synthesis of silver nanowires and nanoparticles have been previously reported, this new route can generate structures with diameters less than 10 nanometres, which has previously been very challenging.

Allendorf’s Chemical Science Edge article is available to download for free.

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Metal-free polymers have the potential to replace toxic metal catalysts in hydrocarbon oxidation reactions, according to an international team of chemists.

Yong Wang, at the Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany, and colleagues replaced some of the carbon atoms in graphitic carbon nitride with boron. The resulting polymeric material was better than previous biomimetic homogeneous oxidation catalysts at oxidising substituted aromatics.

Oxidations of sp³ hybridised C-H bonds are challenging because the oxidised products are more reactive than the starting materials and so they tend to over-oxidise. This was not a problem for Wang’s catalyst, which was highly selective at forming ketones or aldehydes.

For more information, download Wang’s Edge article for free.

Sulfonated graphene solid acid catalysts could be cheap, environmentally friendly alternatives to concentrated sulfuric acid for use in industry because they can be recycled, say scientists from China.

Xiaobin Fan, at Tianjin University, and colleagues made the catalyst by adding 4-benzenediazoniumsulfonate to a graphene suspension. When they tested its activity against other catalysts in ethyl acetate hydrolysis, they found that it had comparable activity to concentrated sulfuric acid catalysts and had higher activity than Nafion NR50, a commercial solid acid known for its excellent activity.

Acid sites in most solid catalysts can be degraded by water in reactions, but Fan’s catalyst is stable in water and can be reused without decrease in activity.

To find out more, download the Chemical Science Edge article for free.

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

Amine directed Pd(ii)-catalyzed C-H bond functionalization under ambient conditions 
Benjamin Haffemayer, Moises Gulias and Matthew J. Gaunt 
Chem. Sci., 2011, Advance Article, DOI: 10.1039/C0SC00367K, Edge Article  

Site-specific photocatalytic splitting of methanol on TiO2(110) 
Chuanyao Zhou, Zefeng Ren, Shijing Tan, Zhibo Ma, Xinchun Mao, Dongxu Dai, Hongjun Fan, Xueming Yang, Jerry LaRue, Russell Cooper, Alec M. Wodtke, Zhuo Wang, Zhenyu Li, Bing Wang, Jinlong Yang and Jianguo Hou 
Chem. Sci., 2010, 575-580, DOI: 10.1039/C0SC00316F, Edge Article  

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

Total synthesis of all (-)-agelastatin alkaloids 
Mohammad Movassaghi, Dustin S. Siegel and Sunkyu Han 
Chem. Sci., 2010, 561-566, DOI: 10.1039/C0SC00351D, Edge Article  

Cyclopropenium-activated Beckmann rearrangement. Catalysis versus self-propagation in reported organocatalytic Beckmann rearrangements 
Christine M. Vanos and Tristan H. Lambert 
Chem. Sci., 2010, 705-708, DOI: 10.1039/C0SC00421A, Edge Article  

N-heterocyclic carbenes which readily add ammonia, carbon monoxide and other small molecules
Ulrich Siemeling, Christian Färber, Clemens Bruhn, Michael Leibold, Detlef Selent, Wolfgang Baumann, Moritz von Hopffgarten, Catharina Goedecke and Gernot Frenking 
Chem. Sci., 2010, 697-704, DOI: 10.1039/C0SC00451K, Edge Article  

Diamine ligands in copper-catalyzed reactions 
David S. Surry and Stephen L. Buchwald 
Chem. Sci., 2010, 13-31, DOI: 10.1039/C0SC00107D, Perspective  

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, Advance Article, DOI: 10.1039/C0SC00330A, Edge Article  

Continuous flow multi-step organic synthesis 
Damien Webb and Timothy F. Jamison 
Chem. Sci., 2010, 675-680, DOI: 10.1039/C0SC00381F, Minireview  

The organocatalytic three-step total synthesis of (+)-frondosin B 
Maud Reiter, Staffan Torssell, Sandra Lee and David W. C. MacMillan 
Chem. Sci., 2010, 37-42, DOI: 10.1039/C0SC00204F, Edge Article  

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

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