Chemical Communications Blog

A research group in the US has successfully simplified a crystallographic technique that scientists, bar those behind the original technique, had struggled to get to grips with.

In 2013, Makoto Fujita’s group at the University of Tokyo in Japan unveiled a powerful tool that gave scientists the ability to analyse oils and liquids by x-ray crystallography, a seemingly impossible task. Upon incorporating these compounds into crystalline hosts, their molecules became ordered, and the compounds became susceptible to diffraction. Thus, armed with fresh insight, the method has provided the absolute structures of compounds where we’d previously been left in the dark. Read the full article in Chemistry World»

Read the orginal journal article in ChemComm:
The crystalline sponge method: MOF terminal ligand effects
Timothy R. Ramadhar, Shao-Liang Zheng, Yu-Sheng Chen and Jon Clardy 
Chem. Commun., 2015, Advance Article
DOI: 10.1039/C5CC03840E, Communication

Here are some of the latest referee-recommended articles published in ChemComm – all free to access until 17th July! 

Organoaqueous calcium chloride electrolytes for capacitive charge storage in carbon nanotubes at sub-zero-temperatures
Yun Gao, Zhanbin Qin, Li Guan, Xiaomian Wang and George Z. Chen
Chem. Commun., 2015, Advance Article
DOI: 10.1039/C5CC03048J 

Self-Assembly Pathway of Peptide Nanotubes Formed by a Glutamatic Acid-Based Bolaamphiphile
Emerson Rodrigo DA SILVA, Wendel Alves, Valeria Castelletto, Mehedi Reza, Janne Ruokolainen, Rohanah Hussain and Ian Hamley
Chem. Commun., 2015, Accepted Manuscript
DOI: 10.1039/C5CC03640B 

Mimicking the Active Site of Aldehyde Dehydrogenases:Stabilization of Carbonyl Hydrates through Hydrogen Bonds
A. J. K. Roth, M. Tretbar and C. B. W. Stark
Chem. Commun., 2015, Advance Article
DOI: 10.1039/C5CC02831K 

Graphene Quantum Dots doped Polyaniline Nanofiber as High Performance Supercapacitor Electrode Materials
Sanjoy Mondal, Utpal Rana and SUDIP MALIK
Chem. Commun., 2015, Accepted Manuscript
DOI: 10.1039/C5CC03981A 

Mesoporous Crystalline-Amorphous Oxide Nanocomposite Network for High-Performance Lithium Storage
Yiting Peng, Zheng Chen, Zaiyuan Le, Hexing Li, Qunjie Xu and Yunfeng Lu
Chem. Commun., 2015, Accepted Manuscript
DOI: 10.1039/C5CC03534A 

Aqueous light driven hydrogen production by a Ru–ferredoxin–Co biohybrid
S. R. Soltau, J. Niklas, P. D. Dahlberg, O. G. Poluektov, D. M. Tiede, K. L. Mulfort and L. M. Utschig
Chem. Commun., 2015,51, 10628-10631
DOI: 10.1039/C5CC03006D 

Most organic chemists asked to imagine a macrocycle with 19 atoms in the backbone, and with three alkenes and one alkyne, would likely place at least two of the alkenes in conjugation, especially if they were familiar with macrolide antibiotic rifamycin. 

Conjugated dienes are usually perceived as most stable; naturally-occurring macrocycles with skipped or non-conjugated dienes are a synthetically challenging class of compounds with biological activity.

In a recent Chemical Communications article, the research groups of Professor Ian Fairlamb and Professor Richard Taylor describe an elegant regio- and stereoselective synthetic approach to an analogue of 19-membered macrocycle phacelocarpus 2-pyrone A. The target compound is distinctly challenging due to its unique, multiple 1,4-pattern of skipped alkene and alkyne functionality.

Several effective synthetic campaigns of 1,4-diene motifs capitalize on alkene/alkyne metathesis or cross-coupling strategies. However, most methods lack stereoselectivity. In contrast, Fairlamb, Taylor and co-workers achieved the construction of the macrocycle in 6.5% yield over 11 steps in the longest linear route.  In doing so, they stereoselectively combined three fragments in the first use of bifunctional (Z)-vinylstannyl-posphonium salt as a nucleophile with stepwise Wittig and Stille reactions. 

The successful Z-stereoselectivity of the Wittig reaction was accompanied by the full retention of the Z-vinyl stannane functionality.  While stereoselectivity in the Stille cross-coupling was anticipated as problematic due to the sensitive nature of the allylic vinyl ether moiety in the substrate, the authors were pleased that the macrocyclization succeeded with an E:Z ratio of 5:1.

To discover all the synthetic details about the chemistry from the Fairlamb and Taylor groups, read the ChemComm article in full – it’s free to access* until 3rd July:
Macrocyclic polyenynes: a stereoselective route to vinyl-ether-containing skipped diene systems
Thomas O. Ronson, Martin H. H. Voelkel, Richard J. K. Taylor and Ian J. S. Fairlamb
Chem. Commun., 2015, 51, 8034-8036
DOI: 10.1039/C5CC02091C

Also of interest may be the recently published Chemical Science Perspective Article “Macrocycles: lessons from the distant past, recent developments, and future directions” by Organic and Biomolecular Chemistry Editorial Board Chair Professor Andrei K. Yudin (Chem. Sci., 2015, 6, 30-49).

*Access is free through a registered RSC account – click here to register

Dr. Tezcan Guney is a web writer for Chemical Society Reviews, Chemical Science and Chemical Communications. Dr. Guney received his Ph.D. from the Department of Chemistry at Iowa State University with Prof. George Kraus, where he focused on the synthesis of biologically active polycyclic natural products and multifunctional imaging probes. Currently, he is a postdoctoral research scholar at the Memorial Sloan-Kettering Cancer Center in New York with Prof. Derek Tan, contributing to the efforts to access biologically active small molecules using the diversity-oriented synthetic approach.

Researchers from the UK have developed a straightforward strategy for making compounds that have the potential to become clinical drugs. By cleverly combining robust chemistry and simple starting materials, the team accessed numerous small, diverse molecules with properties suitable for drug screening.

Even the most successful drug starts small. Pharmaceutical companies screen vast libraries of small compounds for the next lead – a molecule that interacts with a given target such as a protein or receptor. Through structural optimisation, tweaking and testing, the lead then grows into a full-fledged drug, ready for biological trials.

A minimal toolkit of reactions turns small polyfunctional molecules into diverse scaffolds

Read the full article in Chemistry World»

Read the original journal article in ChemComm – it’s free to access until 1st July:
Synthesis of amphiphilic polysuccinimide star copolymers for responsive delivery in plants
Mingsheng Chen, Shaun P. Jensen, Megan R. Hill, Gloria Moore, Zhenli He and Brent S. Sumerlin 
Chem. Commun., 2015, Advance Article
DOI: 10.1039/C5CC02726H, Communication

US scientists have developed a stimuli-responsive, biodegradable star-shaped copolymer for targeted nutrient and pesticide delivery in plants. Controlled release to the phloem at an elevated pH makes these nanocarriers a promising step forward in modern agriculture.

Polymeric nanocarriers have already been studied for site-specific and controlled drug release in medicine, but their agricultural potential remains relatively unexplored. Existing methods of plant nutrient and pesticide delivery offer low efficiency so a site-specific strategy is in demand.

Read the full article in Chemistry World»

Read the original journal article in ChemComm – it’s free to access until 29th June:
Synthesis of amphiphilic polysuccinimide star copolymers for responsive delivery in plants
Mingsheng Chen, Shaun P. Jensen, Megan R. Hill, Gloria Moore, Zhenli He and Brent S. Sumerlin 
Chem. Commun., 2015, Advance Article
DOI: 10.1039/C5CC02726H, Communication

Tweaking the natural substrates of terpene synthase enzymes could lead to less toxic pesticides and swathes of other important biologically-active compounds, according to UK researchers.

Terpene synthases generate a huge variety of natural compounds with important functions in all forms of life. Many plants emit volatile terpenes to repel predators, including insects, so there is considerable interest in creating new terpene analogues for pesticides. Insects, however, have a very sophisticated ‘nose’ for these compounds and may ignore even closely-related analogues.

Read the full article in Chemistry World»

Read the original journal article ChemComm – it’s free to access until 22nd June:
Novel olfactory ligands via terpene synthases
Sabrina Touchet, Keith Chamberlain, Christine M. Woodcock, David J. Miller, Michael A. Birkett, John A. Pickett and Rudolf K. Allemann 
Chem. Commun., 2015,51, 7550-7553
DOI: 10.1039/C5CC01814E, Communication