A Resorcin[4]arene-Based Phosphite-Phosphine Ligand for the Branched-Selective Hydroformylation of Alkyl Alkenes.

Synthesis of a chelating phosphite-phosphine ligand from a tris(quinoxaline) extended resorcin[4]arene and its application in the rhodium-catalyzed hydroformylation of terminal alkyl alkenes are reported. Rhodium complexes are formed within the cavity of the macrocycle and branched-selective hydroformylation of 1-octene with a / ratio of 5.9 has been achieved at 60 °C under 1:1 H/CO (20 bar).

Receptor-Targeted Peptide Conjugates Based on Diphosphines Enable Preparation of Tc and Re Theranostic Agents for Prostate Cancer.

Benchtop Mo/Tc and W/Re generators enable economical production of molecular theranostic Tc and Re radiopharmaceuticals, provided that simple, kit-based chemistry exists to radiolabel targeting vectors with these radionuclides. We have previously described a diphosphine platform that efficiently incorporates Tc into receptor-targeted peptides. Here, we report its application to label a prostate-specific membrane antigen (PSMA)-targeted peptide with Tc and Re for diagnostic imaging and systemic radiotherapy of prostate cancer.

A multifault earthquake threat for the Seattle metropolitan region revealed by mass tree mortality.

Compound earthquakes involving simultaneous ruptures along multiple faults often define a region's upper threshold of maximum magnitude. Yet, the potential for linked faulting remains poorly understood given the infrequency of these events in the historic era. Geological records provide longer perspectives, although temporal uncertainties are too broad to clearly pinpoint single multifault events.

Versatile Diphosphine Chelators for Radiolabeling Peptides with Tc and Cu.

We have developed a diphosphine (DP) platform for radiolabeling peptides with Tc and Cu for molecular SPECT and PET imaging, respectively. Two diphosphines, 2,3-bis(diphenylphosphino)maleic anhydride (DP) and 2,3-bis(di--tolylphosphino)maleic anhydride (DP), were each reacted with a Prostate Specific Membrane Antigen-targeted dipeptide (PSMAt) to yield the bioconjugates DP-PSMAt and DP-PSMAt, as well as an integrin-targeted cyclic peptide, RGD, to yield the bioconjugates DP-RGD and DP-RGD. Each of these DP-PSMAt conjugates formed geometric /-[MO(DP-PSMAt)] (M = Tc, Tc, Re; X = Ph, Tol) complexes when reacted with [MO] motifs.

Diphosphine Bioconjugates via Pt(0)-Catalyzed Hydrophosphination. A Versatile Chelator Platform for Technetium-99m and Rhenium-188 Radiolabeling of Biomolecules.

The ability to append targeting biomolecules to chelators that efficiently coordinate to the diagnostic imaging radionuclide, Tc, and the therapeutic radionuclide, Re, can potentially enable receptor-targeted "theranostic" treatment of disease. Here we show that Pt(0)-catalyzed hydrophosphination reactions are well-suited to the derivatization of diphosphines with biomolecular moieties enabling the efficient synthesis of ligands of the type PhPCHCHP(CHCH-Glc) (, where Glc = a glucose moiety) using the readily accessible PhPCHCHPH and acryl derivatives. It is shown that hydrophosphination of an acrylate derivative of a deprotected glucose can be carried out in aqueous media.

Heterometathesis of diphosphanes (RP-PR) with dichalcogenides (R'E-ER', E = O, S, Se, Te).

The reactions of RP-PR with R'E-ER', (where E = Se, S, O, Te) to give RP-ER' have been explored experimentally and computationally. The reaction of PhP-PPh with PhSe-SePh gives PhP-SePh (1) rapidly and quantitatively. The P-P/Se-Se reaction is inhibited by the addition of the radical scavenger TEMPO which is consistent with a radical mechanism for the heterometathesis reaction.

Reply to the 'Comment on "In Defence of Oxidation States"' by J. C. Green, , 2022, 51, DOI: 10.1039/D1DT02930D.

We reiterate and reinforce some of the points concerning oxidation states and the Covalent Bond Classification method we made in the Perspective article entitled 'In Defence of Oxidation States' including a brief discussion of the relative merits of the terms 'metathesis' and 'redox' when considering addition across a metal-metal bond.

In defence of oxidation states.

In this Perspective, some of the criticisms which have been made concerning the use of oxidation states are addressed, particularly in the context of the teaching of inorganic chemistry. The Oxidation State method and the Covalent Bond Classification method are compared and contrasted, and it is concluded that while each method has its strengths and weaknesses, both are important in teaching and it should be recognized that no single model or method is appropriate in all circumstances.

One-step, kit-based radiopharmaceuticals for molecular SPECT imaging: a versatile diphosphine chelator for Tc radiolabelling of peptides.

Radiotracers labelled with technetium-99m (Tc) enable accessible diagnostic imaging of disease, provided that radiotracer preparation is simple. Whilst Tc radiopharmaceuticals for imaging perfusion are routinely prepared from kits, and regularly used in healthcare, there are no Tc-labelled receptor-targeted radiopharmaceuticals in widespread clinical use. This is in part due to the multistep radiosyntheses required for the latter.

Chemical analysis of fresh and aged Australian e-cigarette liquids.

Objectives: To assess the chemical composition of electronic cigarette liquids (e-liquids) sold in Australia, in both their fresh and aged forms.

Design, Setting: Gas chromatography-mass spectrometry analysis of commercial e-liquids sold in Australia (online and physical stores).

Main Outcome Measures: Chemical composition of 65 Australian e-liquids - excipients/solvents, flavouring chemicals, other known e-liquid constituents (including nicotine), and polycyclic aromatic hydrocarbons - before and after an accelerated ageing process that simulated the effects of vaping.

Rhenium Complexes Bearing Tridentate and Bidentate Phosphinoamine Ligands in the Production of Biofuel Alcohols via the Guerbet Reaction.

We report a variety of rhenium complexes supported by bidentate and tridentate phosphinoamine ligands and their use in the formation of the advanced biofuel isobutanol from methanol and ethanol. Rhenium pincer complexes - are effective catalysts for this process, with giving isobutanol in 35% yields, with 97% selectivity in the liquid fraction, over 16 h with catalyst loadings as low as 0.07 mol %.

Multi-nuclear, high-pressure, FlowNMR spectroscopic study of Rh/PPh - catalysed hydroformylation of 1-hexene.

The hydroformylation of 1-hexene with 12 bar of 1 : 1 H2/CO in the presence of the catalytic system [Rh(acac)(CO)2]/PPh3 was successfully studied by real-time multinuclear high-resolution FlowNMR spectroscopy at 50 °C. Quantitative reaction progress curves that yield rates as well as chemo- and regioselectivities have been obtained with varying P/Rh loadings. Dissolved H2 can be monitored in solution to ensure true operando conditions without gas limitation.

Radical-initiated P,P-metathesis reactions of diphosphanes: evidence from experimental and computational studies.

By combining the diphosphanes Ar2P-PAr2, where Ar = C6H5, 4-C6H4Me, 4-C6H4OMe, 3,5-C6H3(CF3)2, it has been shown that P,P-metathesis generally occurs rapidly under ambient conditions. DFT calculations have shown that the stability of unsymmetrical diphosphanes Z2P-PZ'2 is a function of the difference between the Z and Z' substituents in terms of size and electronegativity. Of the mechanisms that were calculated for the P,P-metathesis, the most likely was considered to be one involving Ar2P˙ radicals.

Cytotoxic (,-1,3,5-triaminocyclohexane)ruthenium(II)-diphosphine complexes; evidence for covalent binding intercalation with DNA.

We report cytotoxic ruthenium(ii) complexes of the general formula [RuCl(cis-tach)(diphosphine)]+ (cis-tach = cis-cis-1,3,5-triaminocyclohexane) that have been characterised by 1H, 13C and 31P{1H} NMR spectroscopy, mass spectrometry, X-ray crystallography and elemental analysis. The kinetics of aquation and stability of the active species have been studied, showing that the chlorido ligand is substituted by water at 298 K with first order rate constants of 10-2-10-3 s-1, ideal for potential clinical use as anti-tumour agents. Strong interactions with biologically relevant duplex and quadruplex DNA models correlate with the activity observed with A549, A2780 and 293T cell lines, and the degree of activity was found to be sensitive to the chelating diphosphine ligand.

Communicating marine climate change impacts in the Caribbean and Pacific regions.

The scientific literature on marine and coastal climate change has proliferated in recent decades. Translating and communicating this evidence in a timely, and accessible manner, is critical to support adaptation, but little is being done to summarise the latest science for decision makers. For Small Island Developing States (SIDS), which are highly vulnerable to marine and coastal climate change impacts, there is an urgent need to make the latest science readily available to inform national policy, leverage climate funding and highlight their vulnerability for international reports and climate negotiations.

Ring size effects in cyclic fluorophosphites: ligands that span the bonding space between phosphites and PF.

The 5- to 8-membered cyclic fluorophosphites L5-8 have been prepared from the corresponding chlorophosphites which are derived from dihydroxyarenes or bis(trimethylsiloxy)arenes. Ligand L5 is very sensitive to hydrolysis but L6-8 are much more kinetically robust. The coordination chemistry of L5-8 has been explored with Mo(0), Pt(0) and Rh(i) and it is shown that the π-acceptor properties of L5-8 increase with decreasing ring size.

Palladium-catalysed alkyne alkoxycarbonylation with P,N-chelating ligands revisited: a density functional theory study.

A revised in situ base mechanism of alkyne alkoxycarbonylation via a Pd catalyst with hemilabile P,N-ligands (PyPPh2, Py = 2-pyridyl) has been fully characterised at the B3PW91-D3/PCM level of density functional theory. Key intermediates on this route are acryloyl and η3-propen-1-oyl complexes that readily undergo methanolysis. With two hemilabile P,N-ligands and one or both of them protonated, the overall computed barrier is 16.

Inorganic Triphenylphosphine.

A completely inorganic version of one of the most famous organophosphorus compounds, triphenylphosphine, has been prepared. A comparison of the crystal structures of inorganic triphenylphosphine, PBaz (where Baz=B H N H ) and PPh shows that they have superficial similarities and furthermore, the Lewis basicities of the two compounds are remarkably similar. However, their oxygenation and hydrolysis reactions are starkly different.

Patients With Cirrhosis Require More Fecal Microbiota Capsules to Cure Refractory and Recurrent Clostridium difficile Infections.

The incidence of recurrent and refractory Clostridium difficile (rCDI) is increasing. Cirrhotic patients are at increased risk of CDI as a result of frequent hospitalizations, prophylactic antibiotics, proton pump inhibitor use, and comorbidities. In addition, cirrhotic patients with CDI have a higher mortality rate, longer length of stay, and a higher cost compared with noncirrhotic patients.

Pyrrolidines and Piperidines by Ligand-Enabled Aza-Heck Cyclizations and Cascades of N-(Pentafluorobenzoyloxy)carbamates.

Ligand-enabled aza-Heck cyclizations and cascades of N-(pentafluorobenzoyloxy)carbamates are described. These studies encompass the first examples of efficient non-biased 6-exo aza-Heck cyclizations. The methodology provides direct and flexible access to carbamate protected pyrrolidines and piperidines.

Spin Changes Accompany Ultrafast Structural Interconversion in the Ground State of a Cobalt Nitrosyl Complex.

Ultrafast, reversible intersystem crossing (ISC) is reported under ambient conditions for the electronic ground state of the pentacoordinate cobalt nitrosyl complexes, [CoX (NO)(PMePh ) ] (X=Cl, Br), in solution. ISCs on such short timescales are more typically observed in electronically excited states reached by absorption of ultraviolet or visible light. Singlet and triplet electron spin states of the complex, corresponding to two different isomers, are populated at room temperature, and the two isomers exchange on a timescale of a few picoseconds.

2-Pyridyl substituents enhance the activity of palladium-phospha-adamantane catalysts for the methoxycarbonylation of phenylacetylene.

The synthesis of a series of CgPAr ligands is reported, where CgP is the 6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamant-6-yl moiety and Ar = 2-pyridyl (L2), 3-pyridyl (L3), 2-pyrimidyl (L4), 4-R-2-pyridyl [R = Me (L5a), CF (L6a), SiMe (L7a)] or 6-R-2-pyridyl [R = Me (L5b), CF (L6b), SiMe (L7b). Testing of these ligands in the Pd-catalysed methoxycarbonylation of phenylacetylene reveals that the activity and branched selectivity of the catalysts derived from these ligands varies as a function of the N-heterocycle, with the catalyst derived from L5b being the most active of those tested. This, together with the poor performance of catalysts derived from L3 supports the hypothesis that the catalysis proceeds by a "proton shuttling" mechanism, an idea that previously had only been applied to arylphosphines.

Microfibres and macroscopic films from the coordination-driven hierarchical self-assembly of cylindrical micelles.

Anisotropic nanoparticles prepared from block copolymers are of growing importance as building blocks for the creation of synthetic hierarchical materials. However, the assembly of these structural units is generally limited to the use of amphiphilic interactions. Here we report a simple, reversible coordination-driven hierarchical self-assembly strategy for the preparation of micron-scale fibres and macroscopic films based on monodisperse cylindrical block copolymer micelles.

Aminophobanes: hydrolytic stability, tautomerism and application in Cr-catalysed ethene oligomerisation.

9-Amino-9-phosphabicyclo[3.3.1]nonanes, (PhobPNHR'; R = Me or (i)Pr) are readily prepared by aminolysis of PhobPCl and are significantly less susceptible to hydrolysis than the acyclic analogues Cy2PNHR'.