This special issue of the Journal contains a collection of papers authored by participants at the 8th Heron Conference on Reactive Intermediates and Unusual Molecules, which was held at Ayers Rock Resort.

The electronic spectra of isotopologues of protonated coronene in the gas phase were measured below 10 K in a cryogenic trap. Wavelength shifts to the (1) ¹A′ ← X ¹A′ transition upon ¹³C substitution are observed and additional features appear in the spectrum of monodeuterated coronene. The implications for potential detection in interstellar clouds are considered.

A new, chromatography-free synthesis for the preparation of an experimental UV-B absorber is reported. A key step of the process is a one-pot partial reduction of a symmetrical imide with a sequential dehydration step. The synthesis uses several continuous-flow steps to increase sample throughput and was used to prepare approximately 0.5 kg of the material over several batches in >99 % purity.

The Burgess reagent is reexamined to shed light on its structure and reactivity. Theoretical modelling of this useful reagent suggests certain parallels between N→B dative bonding in amine boranes and the dative N→S bond of the Burgess reagent. These bonding and reactivity features are evident in the solid state structure of the Burgess reagent.

Colorimetric identification of oil spills is demonstrated by using an array of photochromic molecules.

A synthetic method to prepare 1-naphthyl ketones from gold(i)-catalysed oxidative cycloisomerisation of 1,6-diyne acetates is described. The proposed mechanism involves cyclopropenation–cycloreversion of the 1,6-diyne motif initiated by a [2,3]-sigmatropic rearrangement. This is followed by nucleophilic attack of the ensuing gold carbenoid species by a molecule of water and autoxidation to give the aromatic product.

Two cyclopropanated phenanthrene derivatives have been synthesized and photolyzed in solution to produce (1-hydroxycyclopropyl)- and (1-hydroxycyclobutyl)carbene. The carbenes rearrange by ring expansion.

1,2,4-Thiadiazole-lissoclinamide 9, a next generation mimic design, was evaluated in silico for metal binding aptitude towards Cu^II ions. DFT calculations suggest that TDA-lissoclinamide may be capable of forming a complex with one Cu^II ion, [Cu(9-H)(H₂O)]⁺. These results underpin future synthetic and experimental metal binding studies.

We report a palladium(ii) carbamate complex resulting from CO₂ activation. The reaction proceeds very fast for a palladium(ii) terminal imido complex and slowly for the related palladium(ii) bisamido complex. Computational analysis suggests a nucleophilic addition mechanism instead of a 1,2-addition for the imido complex.

Branched gold nanoparticles with a sufficiently monodisperse distribution of size were fabricated and self-assembled into a 2D close-packed organisation.

A Ca^II-based MOF with microporous cages containing [(CH₃)₂NH₂]^I cations was synthesised. Its Tb^III-loaded material exhibits the characteristic luminescence of Tb^III ions and can be used as a highly selective and recyclable luminescence probe for detection of Cr^III and Fe^III ions.

A series of new porous organic polymers (POPs) based on the bis-bromo salen ligand containing Mn, Ni, Fe, and Pd metalloligand centres are examined for properties desirable in CO₂ post-combustion capture applications.