Volume 8 Issue 10, October 2016

'Click' chemistry allows for the linking together of chemical modules, however, there are currently no methods that also allow for facile 'declicking' to unlink them. Now, a method has been developed to click together amines and thiols, and then allow a chemically triggered declick reaction to release the original molecular components.

The high stability of aromatic compounds often limits the types of reaction that can be conducted on them. Now, a series of photochemically promoted addition reactions has been used to effect the oxidative dearomatization of benzene derivatives. These reactions provide a suite of versatile new building blocks for chemical synthesis.

The high temperatures and pressures used in heterogeneous catalysis make it difficult to observe catalysts using conventional techniques. Now, adsorbed product molecules on the surface of a single-crystal model catalyst have been observed during catalysis using a custom-built scanning tunnelling microscope that can work in situ.

After remaining elusive for 40 years, 'Kochi's complex', a key intermediate in iron-catalysed cross-coupling, has finally been pinned down, and its structure comes as something of a surprise.

The synthesis of topologically non-trivial compounds requires the manipulation of molecular recognition with an extraordinarily high level of control. Now, DNA four-way junctions have been configured to construct synthetic DNA knots and links, which can then be used to investigate important DNA-processing enzymes.

Identifying a non-enzymatic method of replicating RNA for multiple cycles has been problematic because rapid strand reannealing outcompetes slow non-enzymatic template copying. Now, oligoarginine peptides have been shown to inhibit reannealing while still allowing short primers and activated monomers to bind to the template strand, facilitating the next round of template copying.

Dearomatization reactions that can simultaneously introduce functionality are valuable transformations that are largely underdeveloped. Now, a synthetic strategy based on the combination of arenophiles with catalytic dihydroxylation reactions enables rapid and controlled access to synthetically useful cyclohexene and cyclohexadiene derivatives from readily available arene starting materials.

During the Fischer-Tropsch catalytic reaction, alkanes are synthesized from carbon monoxide and hydrogen at high pressure and temperature. Now it is shown using scanning tunnelling imaging of a cobalt surface during reaction that linear alkane product molecules of a specific length self-assemble on terraces, facilitating the desorption of new product molecules created at step sites.

Force-induced tautomerization in a single porphycene molecule is investigated on a Cu(110) surface at 5 K by using non-contact atomic force microscopy. The force needed to trigger the tautomerization process is quantified by force spectroscopy and theoretical calculations reveal the atomistic mechanism behind the reaction.

The existence (or not) of electronic coherence in homopolymers is dependent on a balance between monomer–monomer interactions and environmental heterogeneity. Now, by understanding how even–odd orbital symmetry influences coherence and produces resistance oscillations as a function of distance—it is shown that DNA sequences can be designed to support coherent charge transport.

A major drawback of molecular ferroelectric crystals, low dimensionality, has now been overcome by ionic plastic crystals. Molecular rotation and phase transitions intrinsic to the crystals make the materials unique molecular ferroelectrics, where the polarization axis direction in a grown crystal can be flexibly altered by applying an electric field.

Hydrogen fluoride has been encapsulated in C₆₀-fullerene using molecular surgery. The quantum rotor system has been studied by NMR and infrared spectroscopy as well as neutron scattering. The fullerene cage causes a small red-shift in the HF rotational and vibrational constants, and shields around 75% of its dipole.

The controlled activation of proteins inside living cells is an important goal in protein design research. Now, a strategy for allosteric activation using coordination chemistry has been demonstrated for two different kinds of neurotransmitter receptors, an ion-channel and a G-protein coupled glutamate receptor.

It has now been shown that amines and thiols can be tethered together through a Meldrum's acid-derived conjugate acceptor for applications ranging from dynamic combinatorial chemistry to biochemistry to polymer chemistry. Furthering the utility of this chemistry, the ability to then chemically ‘declick' back to the unaltered amine and thiol components is also demonstrated.

Selectively degrading the pathogenic, aggregated amyloid state of proteins, without affecting the functional state, is a potential therapeutic strategy for treating amyloid diseases. Now, photooxygenation catalysts that are active only when bound to the cross-β-sheet structure of the amyloid form have been developed.

Lars Öhrström tells of the fleeting, but still tangible, chemistry of dubnium, the heaviest of the group 5 elements.