Autonomous mobile robots for exploratory synthetic chemistry.

Autonomous laboratories can accelerate discoveries in chemical synthesis, but this requires automated measurements coupled with reliable decision-making. Most autonomous laboratories involve bespoke automated equipment, and reaction outcomes are often assessed using a single, hard-wired characterization technique. Any decision-making algorithms must then operate using this narrow range of characterization data.

Exploration of the polymorphic solid-state landscape of an amide-linked organic cage using computation and automation.

Organic cages can possess complex, functionalised cavities that make them promising candidates for synthetic enzyme mimics. Conformationally flexible, chemically robust structures are needed for adaptable guest binding and catalysis, but rapidly exchanging systems are difficult to resolve in solution. Here, we use low-cost calculations and high-throughput crystallisation to identify accessible conformers of a recently reported organic cage by 'locking' them in the solid state.

2D to 3D Reconstruction of Boron-Linked Covalent-Organic Frameworks.

The transformation of two-dimensional (2D) covalent-organic frameworks (COFs) into three-dimensions (3D) is synthetically challenging, and it is typically addressed through interlayer cross-linking of alkene or alkyne bonds. Here, we report the first example of the chemical reconstruction of a 2D COF to a 3D COF with a complete lattice rearrangement facilitated by base-triggered boron hybridization. This chemical reconstruction involves the conversion of trigonal boronate ester linkages to tetrahedral anionic spiroborate linkages.

Fingerprints of Chalcogen Bonding Revealed Through Se-NMR.

Se-NMR is used to characterise several chalcogen bonded complexes of derivatives of the organoselenium drug ebselen, exploring a range of electron demand. NMR titration experiments support the intuitive understanding that chalcogen bond donors bearing more electron withdrawing substituents give rise stronger chalcogen bonds. The chemical shift of the selenium nucleus is also shown to move upfield as it participates in a chalcogen bond.

Experimental Confirmation of a Predicted Porous Hydrogen-Bonded Organic Framework.

Hydrogen-bonded organic frameworks (HOFs) with low densities and high porosities are rare and challenging to design because most molecules have a strong energetic preference for close packing. Crystal structure prediction (CSP) can rank the crystal packings available to an organic molecule based on their relative lattice energies. This has become a powerful tool for the a priori design of porous molecular crystals.

High-resolution structural study on pyridin-3-yl ebselen and its N-methylated tosylate and iodide derivatives.

The crystal structure of the pyridine-substituted benzisoselenazolinone 2-(pyridin-3-yl)-2,3-dihydro-1,2-benzoselenazol-3-one (CHNOSe, 2), related to the antioxidant ebselen [systematic name: 2-phenyl-1,2-benzoselenazol-3(2H)-one, 1], is characterized by strong intermolecular N...

Packing-induced selectivity switching in molecular nanoparticle photocatalysts for hydrogen and hydrogen peroxide production.

Molecular packing controls optoelectronic properties in organic molecular nanomaterials. Here we report a donor-acceptor organic molecule (2,6-bis(4-cyanophenyl)-4-(9-phenyl-9H-carbazol-3-yl)pyridine-3,5-dicarbonitrile) that exhibits two aggregate states in aqueous dispersions: amorphous nanospheres and ordered nanofibres with π-π molecular stacking. The nanofibres promote sacrificial photocatalytic H production (31.

Creating communities and communicating science during COVID-19: From Coast2Coast to Coast2Cast.

The global COVID-19 pandemic has seen extended lockdowns, isolation periods and travel restrictions across many countries around the world since early 2020. Some countries, such as Australia and New Zealand, closed their international borders in early 2020 preventing researchers travelling to other parts of the world. To facilitate the exposure of our students' work, and for them to meet international researchers, as well as foster a sense of coastal community, we started a zoominar series (seminars via Zoom) in April 2020.

Synthesis of acyloin natural products by Mukaiyama hydration.

The acyloin natural products are a family of bioactive compounds isolated from fungi and myxobacteria. The total synthesis of 7 members of the acyloin family was achieved a HWE reaction followed by Mukaiyama-Isayama hydration, using novel Co(II) and Co(III) Schiff base SALPN complexes as catalysts for the key enone hydration step. Furthermore, we have shown that a mild acyloin rearrangement is possible under Mukaiyama hydration conditions, which was crucial in the success of this approach.

Simulating chalcogen bonding using molecular mechanics: a pseudoatom approach to model ebselen.

The organoselenium compound ebselen has recently been investigated as a treatment for COVID-19; however, efforts to model ebselen in silico have been hampered by the lack of an efficient and accurate method to assess its binding to biological macromolecules. We present here a Generalized Amber Force Field modification which incorporates classical parameters for the selenium atom in ebselen, as well as a positively charged pseudoatom to simulate the σ-hole, a quantum mechanical phenomenon that dominates the chemistry of ebselen. Our approach is justified using an energy decomposition analysis of a number of density functional theory-optimized structures, which shows that the σ-hole interaction is primarily electrostatic in origin.

CHAL336 Benchmark Set: How Well Do Quantum-Chemical Methods Describe Chalcogen-Bonding Interactions?

We present the CHAL336 benchmark set-the most comprehensive database for the assessment of chalcogen-bonding (CB) interactions. After careful selection of suitable systems and identification of three high-level reference methods, the set comprises 336 dimers each consisting of up to 49 atoms and covers both σ- and π-hole interactions across four categories: chalcogen-chalcogen, chalcogen-π, chalcogen-halogen, and chalcogen-nitrogen interactions. In a subsequent study of DFT methods, we re-emphasize the need for using proper London dispersion corrections when treating noncovalent interactions.

Optimising molecular rotors to AIE fluorophores for mitochondria uptake and retention.

Molecular rotors exhibit fluorescence enhancement in a confined environment and thus have been used extensively in biological imaging. However, many molecular rotors suffer from small Stokes shift and self-aggregation caused quenching. In this work, we have synthesised a series of red emissive molecular rotors based on cationic α-cyanostilbene.

Geologically controlled sandy beaches: Their geomorphology, morphodynamics and classification.

Beaches that are geologically controlled by rock and coral formations are the rule, not the exception. This paper reviews the current understanding of geologically controlled beaches, bringing together a range of terminologies (including embayed beaches, shore platform beaches, relict beaches, and perched beaches, among others) and processes, with the aim of exploring the multiple ways in which geology influences beach morphology and morphodynamics. We show how in addition to sediment supply, the basement geology influences where beaches will form by providing accommodation, and in the cross-shore, aspects of rock platform morphology such as elevation and slope are also important.

Experimental evidence of chalcogen bonding at oxygen.

An o-nitro-O-aryl oxime was observed to exhibit a short OO contact, which exhibited characteristics consistent with a chalcogen bond. The O-N bond length of the oxime was appreciably longer than the expected value, and NBO calculations indicated the presence of a n(O) → σ(O-N) orbital delocalisation. Topological analysis of the experimental electron density of two analogues shows the presence of a bond path between the two oxygen atoms, with ρ(r) and ∇2ρ(r) values consistent with an electrostatic interaction.

Structures of the hydrate and dihydrate forms of the DNA-binding radioprotector methyl-pro-amine.

Methyl pro-amine {,,3-trimethyl-4-[6-(4-methyl-piperazin-1-yl)-1,3'-[2,5'-bibenzo[]imidazol]-2'-yl]aniline}, CHNO, crystallized as both a dihydrate, CHN·2HO, and monohydrate, CHN·HO, form from water in the presence of β-cyclo-dextrin, in the 2/ and 2/ space groups, respectively. The two structures adopt different conformations and tautomeric forms as a result of the differing crystal packing as dictated by hydrogen-bonding inter-actions. The dihydrate crystallizes as a three-dimensional hydrogen-bonded network, while the monohydrate crystallizes as a two-dimensional hydrogen-bonded network.