Image reproduced with permission of Christophe CoperetPapers published in this issue include:A combined picture from theory and experiments on water oxidation, oxygen reduction and proton pumping Per E. M. Siegbahn and Margareta R. A. Blomberg, Dalton Trans., 2009, DOI: 10.1039 Recent computational studies of C-H bond activation at late transition metal systems are discussed and processes where lone pair assistance via heteroatom co-ligands or carboxylates are highlighted as a particularly promising means of cleaving C-H bonds. The term 'ambiphilic metal ligand activation' (AMLA) is introduced to describe such reactions.

Halogen‐ and chalcogen‐based σ‐hole interactions have recently received increased interest in non‐covalent organocatalysis. However, the closely related pnictogen bonds have been neglected. In this study, we introduce conceptually simple, neutral, and monodentate pnictogen‐bonding catalysts. Solution and in silico binding studies, together with high catalytic activity in chloride abstraction reactions, yield compelling evidence for operational pnictogen bonds. The depth of the σ holes is easily varied with different substituents. Comparison with homologous halogen‐ and chalcogen‐bonding catalysts shows an increase in activity from main group VII to V and from row 3 to 5 in the periodic table. Pnictogen bonds from antimony thus emerged as by far the best among the elements covered, a finding that provides most intriguing perspectives for future applications in catalysis and beyond.

This study marks chemical space available for pnictogen-bonding catalysis, and demonstrates that reactivity accessible in this space is unique.

In this communication, we introduce transmembrane anion transport with pnictogen-bonding compounds and compare their characteristics with chalcogen-and halogen-bonding analogs. Tellurium-centered chalcogen bonds are at least as active as antimony-centered pnictogen bonds, whereas iodine-centered halogen bonds are three orders of magnitude less active. Irregular, voltage-dependent single-channel currents, high gating charges, efficient dye leakage and small Hill coefficients support the formation of bulky, membrane-disruptive supramolecular amphiphiles by tris(perfluorophenyl)stibanes that bind anions "too strongly." In contrast, the chalcogen-bonding bis(perfluorophenyl)tellanes do not cause leakage and excel as carriers with nanomolar activity, P(Cl/Na) = 10.4 for anion/cation selectivity and P(Cl/NO3) = 4.5 for anion selectivity. Selectivities are lower with pnictogen-bonding carriers because their membrane-disturbing 3D structure affects also weaker binders (P(Cl/Na) = 2.1, P(Cl/NO3) = 2.5). Their 2D structure, directionality, hydrophobicity and support from proximal anion-π interactions are suggested to contribute to the unique power of chalcogen bonds to transport anions across lipid bilayer membranes. The integration of unorthodox interactions into functional systems is of fundamental importance because it promises access to new activities. 1 Synthetic transport systems 2 have emerged as an attractive tool to assess the functional relevance of such interactions. Realized examples include anion-π interactions in many variations, 1 halogen bonds 3,4 and, more recently, also chalcogen bonds. 5,6 In the following, we elaborate on anion transport with pnictogen bonds in direct comparison to chalcogen and halogen bonds. These so-called s-hole interactions 7,8 originate from highly localized areas of highly positive charge density that appear on heavier and p-block elements. Associated with s* orbitals, the s holes appear at the opposite side of the covalent bonds and deepen with increasing electron deficiency of the atom. As a result, there is one s hole available per atom for halogen bonds, 9 two for chalcogen, 10 three for pnictogen 11,12 and four for tetrel bonds (Figure 1). 7,8 Increasing with polarizability, the depth of the s holes