Themed collection The halogen bond: a new avenue in recognition and self-assembly

Welcome to this themed issue of NJC entitled: ‘The halogen bond: a new avenue in recognition and self-assembly’.

A pair of 2,6-bis(4-ethynylpyridinyl)-4-fluoroaniline XB and HB receptors display solvatochromic absorption and emission.

Halogen bonding between neighboring sulfonyl chloride groups and short fluorine–fluorine contacts supports crystal formation in the title compounds.

A halogen bonding pyrrole-bis(iodotriazolium) motif facilitates rarely observed augmented binding affinities and selective sensing of oxoanions (H₂PO₄⁻ and SO₄²⁻).

Neutral terphenyl-based halogen bond donors form two-point halogen bonding motifs with oxadiazoles in the solid state.

We have synthesized and crystalized 3-Cl-10-I-nido-7,8,9,11-P₂C₂B₇H₇. Quantum chemical calculations have demonstrated that the obtained crystal structure is stabilized by hydrogen, dihydrogen and pnictogen bonds.

Discrete tetraiodide dianions (I₄²⁻) are formed in crystals via halogen bond coordination of I₂ by iodide anions which are pinned in their positions by a network of hydrogen bonds involving a benzoselenazole cyanine dye.

Halogen bonds drive the self-assembly of 2-iodoethynylpyridine and 2- iodoethynyl-1-methyl-imidazole into discrete supramolecular triangles.

A theoretical investigation shows that the Au(I) centre in a variety of complexes can behave as a halogen bond acceptor.

Crystallography and DFT reveal competition between chalcogen bonding and other intermolecular interactions.

Thirty-one examples of crystal structures containing discrete tetraiodide I₄²⁻ dianions were identified from the Cambridge Structural Database (CSD) and analyzed in detail in order to find the factors influencing the geometry of this rare fragment. The intermolecular interactions are at least partially responsible for the changes in the geometry of the dianion.

Experimental evidence on the formation of S⋯S and P⋯S chalcogen bonded complexes between 2,2,4,4-tetrafluoro-1,3-dithiethane and the Lewis bases dimethyl sulfide and trimethylphosphine is obtained using infrared spectroscopy of solutions in liquid krypton.

A specifically designed halogen derivatives of anthrapyrazolone for the selective inhibition of JNKs at lower concentrations with minimal off-target effects on MAPKs.

O–H hydrogen-bond donors and R–CC–I halogen-bond donors are close competitors for suitable acceptor sites in solid-state assembly.

Halogen bonding in triiodide–organoiodine cocrystals.

The ability of meta- and para-diiodotetrafluorobenzene to act as halogen bond donors in crystal engineering has been compared by the synthesis and crystal structure analysis of a family of 20 novel halogen-bonded cocrystals with simple monotopic and ditopic nitrogen-based acceptors.

Matched electron rich halogen bond acceptors and donor have been synthesized and the halogen bonded charge transfer cocrystals characterized.

Interaction of the negative potential area from one molecule with the positive areas I and II from two different molecules produces polymorphs 1 and 2.

Bonding models of halogen bonding help understand how thyroid hormones and xenobiotic inhibitors affect thyroid activity through iodothyronine deiodinase.

Conversely to the H₂O–CF₄ adduct, an appreciable intermolecular bond stabilization by charge transfer is operative in the H₂O–CCl₄ system.

Halogen-bonded and hydrogen-bonded cocrystals of 3-iodoethynylbenzoic acid and several nitrogen-containing heterocycles are formed using mechanochemical and solvent-based slow evaporation methods.

The presence of competing donor sites in L1–L4 influences their reactivity towards dihalogens and interhalogens.

Organic selenocyanates form recurrent chain-like motifs ⋯Se(R)–CN⋯Se(R)–CN⋯ through short and linear chalcogen bonding Se⋯NC interactions. A chelating motif is also observed in a DMF solvate with two neighboring CH₂–SeCN groups linked to the DMF oxygen atom.

The intermolecular quadratic stretching force constants k^calc._σ of a series of hydrogen-bonded and halogen bonded complexes B⋯HX and B⋯XY, where B is N₂, CO, HCCH, C₂H₄, H₂S, PH₃, HCN, or NH₃.

If astatine is generally a stronger halogen-bond donor than iodine, an inversion is sometimes observed owing to the spin–orbit coupling.

Intermolecular contacts in strong anion–π and halogen-bonded complexes follow frontier orbitals (instead of most positive or negative surface potentials) of reactants.

The effect of geometric factors on the assembly of luminescent cocrystals between pyrene or phenanthrene and trihaloperfluorobenzenes.

Alkyl halide guests in cavitands move rapidly and maintain halide to contact with the aryl surfaces of the host.