Volume 4 Issue 3, March 2012

Michelle Francl wonders what it is that makes a molecule elegant.

How do you create a molecular circuit board? Covalently coupling different molecules in a sequential manner in surface-based nanostructures opens up new possibilities and hopes for molecular electronics.

The handedness of supramolecular helices formed from achiral monomers has been controlled by applying rotational and gravitational forces, but at the start of the assembly process only. This demonstrates that a falsely chiral influence is able to induce absolute enantioselection.

A sophisticated palladium(IV)-based species allows nucleophilic fluoride to react as an electrophilic fluorination reagent. This long-awaited reactivity will be especially useful in the preparation of radiochemically labelled molecules for positron emission tomography studies.

Determining molecular bond orders can be a delicate and sophisticated task, especially if the electronic structure of the studied system is complex. Now, two different ab initio methods have revealed that C₂ and analogous species have a fourth bond, rather than the previously assumed maximum of three.

Careful consideration of thermodynamics has allowed the design of nucleic acid probes that are highly specific and virtually unaffected by changes in reaction conditions.

Ultrafast chemical physics follows in the explosive wake of technological innovation, using light and radiation sources to study phenomena at timescales where the boundaries between physics and chemistry dissolve. UCP 2011, the second meeting in a series, explored the current state of the art in ultrafast time-resolved spectroscopy.

Metamaterials are synthetic materials tailored with unusual properties that are not found in nature. It has now been predicted that they could be engineered with negative refractive index through the use of periodic structures via bottom-up self-assembly synthesis.

This Perspective discusses contemporary ideas for enzymatic reactions that invoke a role for fast 'promoting' (or 'compressive') motions or vibrations that, in principle, can facilitate enzyme-catalysed reactions. With an emphasis on hydrogen-transfer reactions, experimental, theoretical and computational approaches that have lent evidence to this controversial hypothesis are discussed.

Enzyme-catalysed reactions can involve significant quantum tunnelling and show kinetic isotope effects with complex temperature dependences. In this Perspective, reaction dynamics and enzyme catalysis are linked to transition-state-theory frameworks. It is shown that a multi-state model using standard transition-state theory can account for complex experimental data without invoking a role for enzyme dynamics.

Adsorbed carbon monoxide typically acts to poison the oxidation of alcohols on heterogeneous catalysts and electrocatalysts. Here, it is shown that carbon monoxide that has been adsorbed irreversibly on a Au(111) surface can act as a promoter for this process by enhancing the scission of C–H bonds in the alcohol to yield the corresponding aldehyde.

The pre-RNA-world hypothesis postulates that RNA was preceded in the evolution of life by a simpler genetic material. Here, Darwinian evolution methods were used to generate a threose nucleic acid (TNA) aptamer. This result provides evidence that TNA could have served as an ancestral genetic system during an early stage of life.

Solving the structure of zeolites is often challenging because of their small particle size. Now, electron crystallography reveals the structure of a family of complex intergrown zeolite materials. These zeolites contain unique pair-wise 12-ring channels that intersect with 10-ring channels, and are promising catalysts for converting gasoline into diesel fuel.

The bonding order of multiply bonded main-group elements is conventionally thought to be limited to triple bonds. Now, using high-level theoretical methods, it is shown that C₂ and its isoelectronic molecules CN⁺, BN and CB⁻ are quadruply bonded, featuring not only one σ - and two π-bonds, but also one weak ‘inverted’ bond.

It is shown here that the proper combination of physical forces can induce chirality during the self-assembly of achiral molecules. Rotation and effective gravity created by high magnetic fields during the nucleation phase, together with the magnetic alignment of the nanoaggregates initially formed, control the enantioselectivity of porphyrin assemblies.

High-fidelity pairing of nucleic acid polymers is important in the development of sensors and for the application of DNA nanotechnology. Here, a set of hybridization probes is described that discriminates single-base changes with high specificity. The probes function robustly across many different temperatures, salinities and nucleic acid concentrations.

The bottom-up construction of covalently linked molecular architectures on surfaces has recently been demonstrated, but only rather simple structures can be obtained in such one-step connection processes. A sequential approach has now been used to induce the selective connection of molecules with a programmed reactivity, enabling network formation with high selectivity.

The oxo groups in the common trans-uranyl ion — present in the majority of known uranium compounds — are linear and inert. Now, a new reduced binuclear uranium–dioxo compound with very strong metal coupling and remarkable air stability has been formed through oxo migration and silylation.

To achieve chemoselective additions of organometallics to carbonyls, it is important to consider the combination of acylating agent and organometallic as a reactive pair rather than either one in isolation. Here, a chemoselective, controlled and general methodology for the conversion of secondary amides to ketones and ketimines is described.

Dan O'Leary examines Harold Urey's decision to name the mass-2 hydrogen isotope 'deuterium'.

The past decade has seen a debate grow on the possibility that the motions of enzymes could influence the contribution that quantum mechanical tunnelling makes to their activity. In this focus we highlight differing views on the significance that structural dynamics has on the reactivity of enzymes.