Oleksandr

Electron transport through multiple hydrogen bonds: Supramolecular junctions bridged with quadruple hydrogen bonds have been constructed and characterized using the scanning tunneling microscopy break junction method. This noncovalent interaction exhibits conductivity comparable to that of covalently conjugated molecular devices and can also be manipulated by the polarity of the solvent environment.

[Communication]
Lin Wang, Zhong-Liang Gong, Shu-Ying Li, Wenjing Hong, Yu-Wu Zhong, Dong Wang, Li-Jun Wan
Angew. Chem. Int. Ed., August 31, 2016, DOI: 10.1002/anie.201605622. Read article

A terrestrial planet candidate in a temperate orbit around Proxima Centauri

Nature 536, 7617 (2016). doi:10.1038/nature19106

Authors: Guillem Anglada-Escudé, Pedro J. Amado, John Barnes, Zaira M. Berdiñas, R. Paul Butler, Gavin A. L. Coleman, Ignacio de la Cueva, Stefan Dreizler, Michael Endl, Benjamin Giesers, Sandra V. Jeffers, James S. Jenkins, Hugh R. A. Jones, Marcin Kiraga, Martin Kürster, Marίa J. López-González, Christopher J. Marvin, Nicolás Morales, Julien Morin, Richard P. Nelson, José L. Ortiz, Aviv Ofir, Sijme-Jan Paardekooper, Ansgar Reiners, Eloy Rodríguez, Cristina Rodrίguez-López, Luis F. Sarmiento, John P. Strachan, Yiannis Tsapras, Mikko Tuomi & Mathias Zechmeister

At a distance of 1.295 parsecs, the red dwarf Proxima Centauri (α Centauri C, GL 551, HIP 70890 or simply Proxima) is the Sun’s closest stellar neighbour and one of the best-studied low-mass stars. It has an effective temperature of only around 3,050 kelvin,

Earth-sized planet around nearby star is astronomy dream come true

Nature 536, 7617 (2016). http://www.nature.com/doifinder/10.1038/nature.2016.20445

Author: Alexandra Witze

Planet orbiting Proxima Centauri is likely to be the focus of future interstellar voyages.

Metallaphotoredox-catalysed sp3–sp3 cross-coupling of carboxylic acids with alkyl halides

Nature 536, 7616 (2016). doi:10.1038/nature19056

Authors: Craig P. Johnston, Russell T. Smith, Simon Allmendinger & David W. C. MacMillan

In the past 50 years, cross-coupling reactions mediated by transition metals have changed the way in which complex organic molecules are synthesized. The predictable and chemoselective nature of these transformations has led to their widespread adoption across many areas of chemical research. However, the construction of a bond between two sp3-hybridized carbon atoms, a fundamental unit of organic chemistry, remains an important yet elusive objective for engineering cross-coupling reactions. In comparison to related procedures with sp2-hybridized species, the development of methods for sp3–sp3 bond formation via transition metal catalysis has been hampered historically by deleterious side-reactions, such as β-hydride elimination with palladium catalysis or the reluctance of alkyl halides to undergo oxidative addition. To address this issue, nickel-catalysed cross-coupling processes can be used to form sp3–sp3 bonds that utilize organometallic nucleophiles and alkyl electrophiles. In particular, the coupling of alkyl halides with pre-generated organozinc, Grignard and organoborane species has been used to furnish diverse molecular structures. However, the manipulations required to produce these activated structures is inefficient, leading to poor step- and atom-economies. Moreover, the operational difficulties associated with making and using these reactive coupling partners, and preserving them through a synthetic sequence, has hindered their widespread adoption. A generically useful sp3–sp3 coupling technology that uses bench-stable, native organic functional groups, without the need for pre-functionalization or substrate derivatization, would therefore be valuable. Here we demonstrate that the synergistic merger of photoredox and nickel catalysis enables the direct formation of sp3–sp3 bonds using only simple carboxylic acids and alkyl halides as the nucleophilic and electrophilic coupling partners, respectively. This metallaphotoredox protocol is suitable for many primary and secondary carboxylic acids. The merit of this coupling strategy is illustrated by the synthesis of the pharmaceutical tirofiban in four steps from commercially available starting materials.

Article

Rotaxanes are interlocked molecules that can undergo sliding and rotational movements and can be used in artificial molecular machines and motors. Here, Simmel and co-workers show a rigid rotaxane structures consisting of DNA origami subunits that can slide over several hundreds of nanometres.

Nature Communications doi: 10.1038/ncomms12414

Authors: Jonathan List, Elisabeth Falgenhauer, Enzo Kopperger, Günther Pardatscher, Friedrich C. Simmel

Swaddling smelly sulfide supramolecularly: Long known for its malodor and toxicity, hydrogen sulfide is the most recently discovered endogenously produced gasotransmitter. The first synthetic receptor for the reversible binding of HS⁻ is reported and characterized spectroscopically in solution and crystallographically.

[Communication]
Matthew D. Hartle, Ryan J. Hansen, Blakely W. Tresca, Samuel S. Prakel, Lev N. Zakharov, Michael M. Haley, Michael D. Pluth, Darren W. Johnson
Angew. Chem. Int. Ed., August 11, 2016, DOI: 10.1002/anie.201605757. Read article

Metal-organic frameworks (MOFs) are an increasingly important family of advanced materials based on open, nanometer-scale metal-organic architectures, whose design and synthesis are based on the directed assembly of carefully designed subunits. We now demonstrate an unexpected link between mineralogy and MOF chemistry by discovering that the rare organic minerals stepanovite and zhemchuzhnikovite exhibit structures found in well-established magnetic and proton-conducting metal oxalate MOFs. Structures of stepanovite and zhemchuzhnikovite, exhibiting almost nanometer-wide and guest-filled apertures and channels, respectively, change the perspective of MOFs as exclusively artificial materials and represent, so far, unique examples of open framework architectures in organic minerals.

Laced up: [2.2]Paracyclophane (pCp) derivatives are capable of programmed self-assembly into extended cofacial π-stacks in solution and in the solid state. The one-dimensional arrangements are homochiral and helically laced-up by a combination of transannular (intramolecular) and intermolecular hydrogen bonds. pCpTA=pCp-4,7,12,15-tetracarboxamide.

[Communication]
Danielle E. Fagnani, Michael J. Meese, Khalil A. Abboud, Ronald K. Castellano
Angew. Chem. Int. Ed., August 03, 2016, DOI: 10.1002/anie.201605286. Read article

Special assemblies of small organic molecules form nano/microscale supramolecular 2D materials in aqueous media. These assemblies can be programmed to disassemble in response to a protein and release its non-covalently bound guest molecules.

[Communication]
Wei Bai, Ziwen Jiang, Alexander E. Ribbe, S. Thayumanavan
Angew. Chem. Int. Ed., August 04, 2016, DOI: 10.1002/anie.201605050. Read article