Chemical Communications Blog

Here are this month’s referee-recommended hot articles – all free to download until 13th April:  

High gas storage capacities and stepwise adsorption in a UiO type metal–organic framework incorporating Lewis basic bipyridyl sites
Liangjun Li, Sifu Tang, Chao Wang, Xiaoxia Lv, Min Jiang, Huaizhi Wu and Xuebo Zhao  
Chem. Commun., 2014,50, 2304-2307
DOI: 10.1039/C3CC48275H, Communication  

Hydrosilylation catalysis by an earth alkaline metal silyl: synthesis, characterization, and reactivity of bis(triphenylsilyl)calcium
Valeri Leich, Thomas P. Spaniol, Laurent Maron and Jun Okuda  
Chem. Commun., 2014,50, 2311-2314
DOI: 10.1039/C3CC49308C, Communication  

Nano-sized heterometallic macrocycles based on 4-pyridinylboron-capped iron(II) clathrochelates: syntheses, structures and properties
Ying-Ying Zhang, Yue-Jian Lin and Guo-Xin Jin  
Chem. Commun., 2014,50, 2327-2329
DOI: 10.1039/C3CC49038F, Communication  

Structural analysis and reactivity of unusual tetrahedral intermediates enabled by SmI2-mediated reduction of barbituric acids: vinylogous N-acyliminium additions to α-hydroxy-N-acyl-carbamides
Michal Szostak, Brice Sautier and David J. Procter  
Chem. Commun., 2014,50, 2518-2521
DOI: 10.1039/C3CC48932A, Communication  

The genesis of a heterogeneous catalyst: in situ observation of a transition metal complex adsorbing onto an oxide surface in solution
Antoine Hervier, Juliette Blanchard, Guylène Costentin, John Regalbuto, Catherine Louis and Souhir Boujday  
Chem. Commun., 2014,50, 2409-2411
DOI: 10.1039/C3CC48838A, Communication  

Click here to see more hot ChemComm articles for March

Anchoring aspirin onto cisplatin could create a cancer treatment capable of overcoming drug resistance in cisplatin resistant cells, new research shows.

Cisplatin, along with other chemotherapeutic drugs, is used to treat various types of cancer, including testicular, ovarian, lung and bladder cancer. However, clinical use of cisplatin is limited by developing resistance, earning it the nickname the ‘penicillin of cancer’. Resistance mechanisms to cisplatin are well defined, but there are still no treatments available to surmount or reverse it.

Upon cellular uptake, asplatin is reduced by ascorbic acid to give cisplatin and aspirin

Read the full article in Chemistry World»

Read the original journal article in ChemComm – it’s free to access until 22nd April:
The Ligation of Aspirin to Cisplatin Demonstrates Significantly Synergistic Effect to Tumor Cells
Qinqin Cheng, Hongdong Shi, Hong-Xia Wang, Yuanzeng Min, Jun Wang and Yangzhong Liu  
Chem. Commun., 2014, Accepted Manuscript, DOI: 10.1039/C4CC00419A

The molecule will readily adjust the size of its opening to accommodate its guest

Chemists in the US have successfully isolated the first anion of a distinctive type of pincer molecule, known as a buckycatcher, and confirmed the extraordinary flexibility it has for encapsulating guest molecules.

The buckycatcher in this study (C₆₀H₂₈) consists of a tetrabenzocyclooctaraene tether that links two corannulene (the smallest and most studied buckybowl) pincers. In previous attempts to isolate this molecule, researchers have had difficulties with solvate formation, as solvents fill the large empty cleft that the buckycatcher uses to encapsulate guest molecules. However, Marina Petrukhina, and co-workers at the University at Albany, State University of New York, have finally managed to elucidate the structure of this rather interesting molecule by developing and carrying out a rather arduous solvent-free method that involved growing the crystals in a vacuum over several months.

The buckycatcher’s flexibiliy has been suggested before, but Petrukhina‘s team provide the first experimental evidence for the adjustability of the tetrabenzocyclooctaraene tether that connects its coranulene pincers and allows them to move closer or further apart to catch guest species.

Read the full article in Chemistry World»

Read the original journal article in ChemComm:
An unsolvated buckycatcher and its first dianion
Alexander V. Zabula, Yulia V. Sevryugina, Sarah N. Spisak, Lesya Kobryn, Renata Sygula, Andrzej Sygula and Marina A. Petrukhina  
Chem. Commun., 2014, Advance Article, DOI: 10.1039/C3CC49451A, Communication

Researchers in Japan have developed the fastest known synthetic route for preparing crystalline microporous solids. The method is currently being scaled-up to meet the increasing demand for these versatile materials in industrial applications.

AlPO4-5 has been commercialised as a vapour adsorbent for refrigerators

Crystalline microporous solids are an important class of inorganic material that impact our everyday lives. Their ordered structures contain arrays of channels and voids several nanometres across, enabling them to selectively and reversibly absorb molecules based on their shapes and sizes. This has led to their widespread use as catalysts, molecular sieves and gas sensors. Research into their potential use as hydrogen storage materials for mobile energy applications is also ongoing.

However, microporous solids often crystallise slowly and typically require several hours to several weeks of hydrothermal treatment to achieve satisfactory yields, limiting their applications on industrial scales. Now, a collaborative effort from the University of Tokyo and the Mitsubishi Chemical Group has led to an ultra-fast method for preparing the aluminophosphate AlPO₄-5. A combination of rapid heating and crystal seeding completes the synthesis within one minute.

Read the full article in Chemistry World»

Read the original journal article in ChemComm:
One-minute synthesis of crystalline microporous aluminophosphate (AlPO4-5) by combining fast heating with a seed-assisted method
Zhendong Liu, Toru Wakihara, Daisuke Nishioka, Kazunori Oshima, Takahiko Takewaki and Tatsuya Okubo  
Chem. Commun., 2014, Advance Article, DOI: 10.1039/C3CC49548E, Communication

Scientists based in the US have developed a new strategy to simplify the chemical synthesis of complex carbohydrates.

TFA simultaneously cleaves all protecting groups from the precursors to form the desired oligosaccharides in quantitative yields

Oligosaccharides are polymeric carbohydrates consisting of a small number of monosaccharide monomers. They are essential to all cellular organisms, playing vital roles in cell recognition and signalling.

Automated methods are routinely used to prepare biomacromolecules such as peptides and nucleic acids, but similar strategies in oligosaccharide synthesis are far less developed. Oligosaccharides contain a large number of hydroxyl groups which normally have to be protected orthogonally, i.e. in such a way that they can be unmasked independently of one another. This poses a great challenge to chemists and has hindered progress towards automated carbohydrate synthesis.

Classical protecting groups for hydroxyl groups include benzyl ethers, which are generally removed via hydrogenolysis or dissolving metal reduction, and acetate, benzoate or pivaloate esters, which are cleaved using base-catalysed hydrolysis. While these reactions are well established, a high level of training in practical organic chemistry is required to carry them out, in contrast to deprotection in automated peptide synthesis, which can be as simple as shaking the protected molecule with an acidic or basic solution.

Xinyu Liu and Yao Li at the University of Pittsburgh have developed a series of acid-cleavable PMB- and NAP-capped 4-hydroxybutanoic acid and 2-(hydroxymethyl)benzoic acid ester-type protecting groups that act as surrogates of acetate and benzoate. Trifluoroacetic acid (TFA) in toluene can simultaneously cleave all of these groups during the final stage of an oligosaccharide assembly to emulate the synthetic efficiency traditionally reserved for peptide chemistry.

Read the full article in Chemistry World»

Read the original journal article in ChemComm:
Tunable Acid-Sensitive Ester Protecting Groups in Oligosaccharide Synthesis
Yao Li and Xinyu Liu  
Chem. Commun., 2013, Accepted Manuscript, DOI: 10.1039/C3CC49205B, Communication