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Targeted alpha therapy offers unique opportunities for the treatment of tumours and infections. Here, we report the development of a new radioimmunoconjugate construct that targets SARS-CoV-2 infected cells, which act as viral reservoirs and promote virus replication and infection spread. The chosen antibody selectively binds to the ACE2-receptor binding domain of the spike protein, and prevents the protein binding to the receptor. Furthermore, the antibody has been radiolabelled with 225Ac, and the therapeutic performance of the resulting radioimmunoconjugate has been demonstrated in vitro against cells mimicking SARS-CoV-2 infection.

The synthesis of three new heteroditopic receptors (5a-c) which are based on thiacalix[4]arenes in the 1,3-alternate conformation is reported herein. These new receptors each have two thiourea moieties linking phenyl groups, two of which are substituted with electron-withdrawing groups at their para-positions, and at the opposite side of the thiacalix[4]arene cavity, with two 2-pyridylmethyl groups. One example (5a) was also characterized by X-ray crystallography. A limited 1H-NMR and UV-vis anion complexation study was conducted. DFT computational determinations indicated that 5c, which has strongly electron-withdrawing NO2 groups, had the most effective recognition ability towards the selected anions. The binding of Ag+ at the 2-pyridyl moieties, and the binding of the anions at the two thiourea NH groups of the p-substituted phenylthioureido moieties, respectively, was also investigated. The appearance of a positive allosteric effect with receptor 5b was also found using 1H-NMR titration experiments.

Here, a new tripodal tricarboxylic acid ligand, 4,4′-(4′-(4′-carboxy-[1,1′-biphenyl]-4-yl)-[2,2′:6′,2′′-terpyridine]-5,5′′-diyl)-dibenzoic acid (H3cbt), was synthesised using a three-step convergent strategy. Subsequent reactions with zinc(ii) nitrate hexahydrate yielded three metal-organic frameworks (MOFs). The three MOFs, [Zn(Hcbt)]·4DMF (1), [Zn(Hcbt)]·4DMSO·1.5H2O·DMF (2), and [Zn(Hcbt)]·2DMF·3H2O (3), each adopt flexible interdigitated 2D net topologies. Framework 1 has DMF-filled channels that retain porosity upon desolvation, with a measured BET surface area of 248 m2 g-1. Framework 2 possesses larger DMSO-containing channels that collapse upon desolvation, resulting in near-equivalent porosity values to framework 1. In silico calculations and topological considerations determined using the geometric simulation software GASP dictate that framework 2 can feasibly alter conformation to approximate 1, but cannot perfectly replicate the interdigitated motif. Framework 3 formed when wet solvents were used to synthesise 1. Interestingly, the interdigitated structure of 3 contains a unique carboxylate binding mode that precludes its subsequent adoption by either 1 or 2 upon their exposure to water. This diverse array of structural considerations recommends this MOF family for modelling using GASP. Interrogating frameworks 1-3 using this software provided insights that justified experimentally observed conformational trends, as well as barriers to interconversion between members of this MOF family. In a broader sense, this work demonstrates the wider applicability of GASP software to modelling structural changes within flexible MOF materials.

For the first time, the formation kinetics and responsible metabolites during the green synthesis of AgNPs were elucidated by sp-ICP-MS and GC-MS.

The toxicity of heavy metals such as lead (Pb), cadmium (Cd) and tin (Sn) has long been known but accidental exposures of large populations to these elements remain unfortunately a topical issue. Chelating agents against Pb, Cd, or Sn poisoning are still limited to classical ligands such as ethylenediamine tetraacetic acid (EDTA). Here, we evaluate the ability of 3,4,3-LI(1,2-HOPO) (L4-), an octadentate ligand currently under evaluation for actinide decorporation, to bind Pb, Cd and Sn metal ions in aqueous solutions. This ligand forms 1:1 complexes with Pb(ii), Cd(ii) and Sn(iv) as well as bimetallic 2:1 species with Pb(ii) and Cd(ii), all of which were characterized by high resolution mass spectrometry and spectrophotometric titrations. The 3,4,3-LI(1,2-HOPO) ligand exhibits an extreme affinity for Sn(iv) ions (logβ110 > 40), with the complex remaining stable from highly acidic conditions to alkaline media (from 3 M HCl to pH 8). Single crystals of the neutral complex [SnIV3,4,3-LI(1,2-HOPO)·3H2O] were obtained and its structure determined, revealing a chiral conformation. Although not initially designed for hexacoordinated metals such as Pb(ii) and Cd(ii), the octadentate ligand shows promise for the in vitro or in vivo sequestration of toxic heavy metals, as evidenced by decorporation experiments performed in mice contaminated with 210Pb(ii) and treated with either EDTA or 3,4,3-LI(1,2-HOPO).

Studies of oxygen-isotope-exchanges in two classes of polyoxoions have uncovered some similarities in reaction steps that are also consistent with mineral-dissolution studies. The molecules were polyoxocations of Group 13 and polyoxoanions of Group 5, and the work was motivated by a desire to understand the dissolution of oxide minerals at the molecular scale. Experimentally, oxygen-isotope-exchange rates are found to be intensely sensitive to single-atom substitutions in the structures, even at sites that are otherwise inert. Exchange rates for different structural oxygen sites span several orders of magnitude, yet most oxygens within a molecule exhibit similar pH dependencies to isotopic exchange and these seem to reflect an average proton affinity of the ion. Single-atom substitutions have a dramatic affect on both the pH dependences of oxygen-isotope-exchanges and the overall reactivity of oxygen sites. Molecular dynamic and electronic-structure calculations identify similar steps in the pathways for exchange - (i) solvation forces cause a near-surface metal to detach from an underlying overbonded oxygen. (ii) This newly undercoordinated metal adds an isotopically normal oxygen as either a water, a hydronium ion or an hydroxide ion. (iii) Protons transfer from these adducts to more basic oxygens in the metastable structure. (iv) The metastability is longlived but access to the metastable state depends on the composition and symmetry of the starting structure, which is why single-atom substitutions are so important. (v) Within the metastable structure, oxygens shuffle positions and the metastable state collapses back into a more stable form. Pathways to form these metastable structures depend on the symmetry and composition of the starting geometry, which probably can't be adequately constrained for meaningful simulation at mineral surfaces.

Reliable transformation of low-cost rare-earth metal oxides to organometallic rare-earth metal complexes is a prerequisite for the advancement of non-aqueous rare-earth metal chemistry. We have recently developed an in situ method to prepare rare-earth alkyl and halide precursors supported by a diamidoferrocene NNTBS, 1,1′-fc(NSiMe2tBu)2, as an ancillary ligand. Herein, we extended the scope of this method to other lanthanide ions including those that are redox active, such as cerium, praseodymium, samarium, terbium, thulium, and ytterbium. Specifically, samarium trisbenzyl could be generated in situ and then converted to the corresponding samarium benzyl or iodide complexes in good yield. However, it was found that ytterbium trisbenzyl could not be formed cleanly and the consequent conversion to ytterbium iodide complex was low yielding. By adapting an alternative route, the desired ytterbium chloride precursor could be obtained in good yield and purity.

We reaffirm our conclusion that secondary deuterium isotope effects on acidity are due to n-σ∗ delocalization that decreases vibrational frequencies and zero-point energies. We reject an electrostatic or inductive explanation that arises from the anharmonicity of the C-H bond. We address calculated values of atomic charges, dipole moments, and dipole-moment derivatives dμ/dr, and we show the isotope effect to be a stereoelectronic phenomenon arising from harmonic vibrations.

Cationic liposomes (CLs) are studied worldwide as carriers of DNA and short interfering RNA (siRNA) for gene delivery and gene silencing, and related clinical trials are ongoing. Optimization of transfection efficiency and silencing efficiency by cationic liposome carriers requires a comprehensive understanding of the structures of CL-nucleic acid complexes and the nature of their interactions with cell membranes as well as events leading to release of active nucleic acids within the cytoplasm. Synchrotron x-ray scattering has revealed that CL-nucleic acid complexes spontaneously assemble into distinct liquid crystalline phases including the lamellar, inverse hexagonal, hexagonal, and gyroid cubic phases, and fluorescence microscopy has revealed CL-DNA pathways and interactions with cells. The combining of custom synthesis with characterization techniques and gene expression and silencing assays has begun to unveil structure-function relations in vitro. As a recent example, this review will briefly describe experiments with surface-functionalized PEGylated CL-DNA nanoparticles. The functionalization, which is achieved through custom synthesis, is intended to address and overcome cell targeting and endosomal escape barriers to nucleic acid delivery faced by PEGylated nanoparticles designed for in vivo applications.