Phosphate selective binding and sensing by halogen bonding tripodal copper(II) metallo-receptors in aqueous media.

Combining the potency of non-covalent halogen bonding (XB) with metal ion coordination, the synthesis and characterisation of a series of hydrophilic XB tripodal Cu(II) metallo-receptors, strategically designed for tetrahedral anion guest binding and sensing in aqueous media is described. The reported metallo-hosts contain a tripodal -symmetric tris-iodotriazole XB donor anion recognition motif terminally functionalised with tri(ethylene glycol) and permethylated β-cyclodextrin functionalities to impart aqueous solubility. Optical UV-vis anion binding studies in combination with unprecedented quantitative EPR anion titration investigations reveal the XB Cu(II) metallo-receptors exhibit strong and selective phosphate recognition over a range of other monocharged anionic species in competitive aqueous solution containing 40% water, notably outperforming a hydrogen bonding (HB) Cu(II) metallo-receptor counterpart.

Halogen Bonding Tripodal Metallo-Receptors for Phosphate Recognition and Sensing in Aqueous-Containing Organic Media.

The anion recognition and electrochemical anion-sensing properties of halogen-bonding (XB) tripodal zinc(II) receptors strategically designed and constructed for tetrahedral anion guest binding are described. The XB tris(iodotriazole)-containing hosts exhibit high affinities and selectivities for inorganic phosphate over other more basic, mono-charged oxoanions such as acetate and the halides in a competitive CD CN/D O (9 : 1 v/v) aqueous solvent mixture. H NMR anion binding and electrochemical voltammetric anion sensing studies with redox-active ferrocene functionalised metallo-tripodal receptor analogues, reveal each of the XB tripods as superior anion complexants when compared to their tris(prototriazole)-containing, hydrogen bonding (HB) counterparts, not only exemplifying the halogen bond as a strong alternative interaction to the traditional hydrogen bond for molecular recognition but also providing rare evidence of the ability of XB receptors to preferentially bind the "harder" phosphate oxoanion over the "softer" and less hydrated halides in aqueous containing media.

Computational analyses of the vibrational spectra of fentanyl, carfentanil and remifentanil.

The infrared (IR) spectra of fentanyl, carfentanil and remifentanil, and protonated salts, are computed using quantum chemistry methods. New experimental FTIR spectra are also reported and compared to the calculations. The accuracy of two density functional theory methods, B3LYP and M06-2X, are tested against higher level theories (MP2) and the experimental data.

A Rationally Designed Supercharged Protein-Enzyme Chimera Self-Assembles to Yield Bifunctional Composite Textiles.

Catalytically active materials for the enhancement of personalized protective equipment (PPE) could be advantageous to help alleviate threats posed by neurotoxic organophosphorus compounds (OPs). Accordingly, a chimeric protein comprised of a supercharged green fluorescent protein (scGFP) and phosphotriesterase from (arPTE) was designed to drive the polymer surfactant (S)-mediated self-assembly of microclusters to produce robust, enzymatically active materials. The chimera scGFP-arPTE was structurally characterized circular dichroism spectroscopy and synchrotron radiation small-angle X-ray scattering, and its biophysical properties were determined.

Self-Immolative System for Disclosure of Reactive Electrophilic Alkylating Agents: Understanding the Role of the Reporter Group.

The development of stable, efficient chemoselective self-immolative systems, for use in applications such as sensors, requires the optimization of the reactivity and degradation characteristics of the self-immolative unit. In this paper, we describe the effect that the structure of the reporter group has upon the self-immolative efficacy of a prototype system designed for the disclosure of electrophilic alkylating agents. The amine of the reporter group (a nitroaniline unit) was a constituent part of a carbamate that functioned as the self-immolative unit.

The accuracy of femoral component rotational measurements using computed tomography-a cadaveric study.

Background: CT scans can be used to assess the rotational alignment of the femoral component following total knee arthroplasty (TKA). This is done by calculating the posterior condylar angle (PCA). However, the methods used may not account for the biomechanical functionality of the TKA components.

Hierarchical Self-Assembled Photo-Responsive Tubisomes from a Cyclic Peptide-Bridged Amphiphilic Block Copolymer.

Typically, the morphologies of the self-assembled nanostructures from block copolymers are limited to spherical micelles, wormlike micelles and vesicles. Now, a new generation of materials with unique shape and structures, cylindrical soft matter particles (tubisomes), are obtained from the hierarchical self-assembly of cyclic peptide-bridged amphiphilic diblock copolymers. The capacity of obtained photo-responsive tubisomes as potential drug carriers is evaluated.

Calculations on the unimolecular decomposition of the nerve agent VX.

It is very difficult to perform experiments on the physical parameters for the thermal decomposition of chemical nerve agents such as VX and computations, therefore, are useful. The reaction dynamics of the gas-phase pericyclic hydrogen transfer of the nerve agent VX is studied computationally. The geometries of the stationary structures are calculated at M06-2X/jul-cc-pVTZ level of theory.

Self-immolative systems for the disclosure of reactive electrophilic alkylating agents.

In this paper we report the design, synthesis and assessment of the first examples of self-immolative systems triggered by non-acidic electrophilic agents such as methyl, allyl or benzylic halides. These systems provide a visual colorimetric disclosure response upon exposure to these electrophilic reagents under mild, basic conditions without the need for the use of analytical instrumentation.

Theoretical Study of Gas-Phase Unimolecular Decomposition of Simulants of the Nerve Agent VX.

In order to further understand and support approaches for the degradation and destruction of toxic chemicals, the thermal decomposition of the nerve agent VX through possible pericyclic hydrogen transfer reactions is investigated using simulant molecules. A total of four simulant molecules are studied. Three of them have only one possible H-transfer site, while the other has two.

National survey of imaging practice for suspected or confirmed plasma cell malignancies.

Objective:: Cross-sectional imaging is now recommended by the National Institute for Health and Care Excellence (NICE) for patients with suspected and newly diagnosed myeloma instead of skeletal survey. The objectives of this study were: (1) To evaluate compliance of current UK imaging practice with reference to National Institute for Health and Care Excellence best-practice clinical guidelines for plasma cell malignancies. (2) To identify factors which may influence diagnostic imaging choices.

Comparison of Binding Affinities of Water-Soluble Calixarenes with the Organophosphorus Nerve Agent Soman (GD) and Commonly-Used Nerve Agent Simulants.

The formation of inclusion complexes of the water-soluble -sulfonatocalix[]arenes, where = 4 or 6, with the Chemical Warfare Agent (CWA) GD, or Soman, and commonly used dialkyl methylphosphonate simulants has been studied by experimental solution NMR methods and by Molecular Mechanics (MMFF) and semi-empirical (PM6) calculations. Complex formation in non-buffered and buffered solutions is driven by the hydrophobic effect, and complex stoichiometry determined as 1:1 for all host:guest pairs. Low affinity complexes ( < 100 M) are observed for all guests, attributed to poor host-guest complementarity and the role of buffer cation species accounts for the low affinity of the complexes.

A Combined Theoretical and Experimental Study of Sarin (GB) Decomposition at High Temperatures.

Theoretical and experimental results are presented for the pyrolytic decomposition of the nerve agent sarin (GB) in the gas phase. High-level quantum chemistry calculations are performed together with a semiclassical transition-state theory for describing quantum mechanical tunneling. The experimental and theoretical results for the temperature dependence of the survival times show very good agreement, as does the calculated and measured activation energy for thermal decomposition.

Selective perrhenate recognition in pure water by halogen bonding and hydrogen bonding alpha-cyclodextrin based receptors.

Alpha-cyclodextrin based anion receptors functionalised with pendant arms containing halogen and hydrogen bond donor motifs display selective association of perrhenate in aqueous media at neutral pH. NMR and ITC anion binding investigations reveal the halogen bonding receptor to be the superior host.

Biasing hydrogen bond donating host systems towards chemical warfare agent recognition.

A series of neutral ditopic and negatively charged, monotopic host molecules have been evaluated for their ability to bind chloride and dihydrogen phosphate anions, and neutral organophosphorus species dimethyl methylphosphonate (DMMP), pinacolyl methylphosphonate (PMP) and the chemical warfare agent (CWA) pinacolyl methylphosphonofluoridate (GD, soman) in organic solvent via hydrogen bonding. Urea, thiourea and boronic acid groups are shown to bind anions and neutral guests through the formation of hydrogen bonds, with the urea and thiourea groups typically exhibiting higher affinity interactions. The introduction of a negative charge on the host structure is shown to decrease anion affinity, whilst still allowing for high stability host-GD complex formation.

Targeting ultrasound remission in early rheumatoid arthritis: the results of the TaSER study, a randomised clinical trial.

Objective: To investigate whether an intensive early rheumatoid arthritis (RA) treat-to-target (T2T) strategy could be improved through the use of musculoskeletal ultrasound (MSUS) assessment of disease activity.

Methods: 111 newly diagnosed patients with RA or undifferentiated arthritis (symptom duration <1 year) were randomised to strategies that aimed to attain either DAS28-erythrocyte sedimentation rate (ESR)<3.2 (control) or a total power Doppler joint count≤1 during a combined DAS28-ESR/MSUS assessment (intervention).

Detection and remediation of organophosphorus compounds by oximate containing organogels.

A series of supramolecular diamide organogels containing a reactive compound for the remediation of organophosphorus (OP) species, in particular OP chemical warfare agents (CWAs), has been prepared in DMSO. The organogels have been found to absorb, encapsulate and decontaminate various OP CWA simulants . At high simulant concentrations the gels also undergo a gel-sol transition releasing high local concentrations of remediation agent.

Contrasting anion recognition behaviour exhibited by halogen and hydrogen bonding rotaxane hosts.

A rotaxane host system containing a novel halogen bonding (XB) 5-iodo-1,2,3-triazole functionalised pyridinium motif, within its axle component, has been prepared via a ring closing metathesis reaction, using chloride as a template. Proton NMR titration experiments, in competitive 1 : 1 CDCl3-CD3OD solvent media, showed the XB rotaxane selectively bound halides over larger, more basic oxoanions. An all hydrogen bonding proto-triazole containing rotaxane analogue was also prepared, which in stark contrast demonstrated a reversal in the anion selectivity trend, with a preference for dihydrogen phosphate over the halides which is unprecedented for an interlocked host system.

Tripodal molecules for the promotion of phosphoester hydrolysis.

A series of low molecular weight tripodal amide/histidine-containing compounds (1-2) have been synthesised and shown to increase the rate of bis-(p-nitrophenyl) phosphate (BNPP) and soman (GD) breakdown in buffered aqueous solution.

VX and VG chemical warfare agents bidentate complexation with lanthanide ions.

Investigations into V-agent interaction with 1,10-phenanthroline nitrate Ln(III) complexes (Eu and Tb) were carried out using luminescence and UV-Vis spectroscopy. Addition of several equivalents of agent resulted in the loss of luminescence intensity and the observation of free 1,10-phenanthroline by UV-Vis. We propose a displacement mechanism in which the V-agent acts as a bidentate ligand to the lanthanide ion.

Supramolecular chemistry and chemical warfare agents: from fundamentals of recognition to catalysis and sensing.

Supramolecular chemistry presents many possible avenues for the mitigation of the effects of chemical warfare agents (CWAs), including sensing, catalysis and sequestration. To-date, efforts in this field both to study fundamental interactions between CWAs and to design and exploit host systems remain sporadic. In this tutorial review the non-covalent recognition of CWAs is considered from first principles, including taking inspiration from enzymatic systems, and gaps in fundamental knowledge are indicated.

Detection of nerve agent via perturbation of supramolecular gel formation.

The formation of tren-based tris-urea supramolecular gels in organic solvents is perturbed by the presence of the nerve agent soman providing a new method of sensing the presence of organophosphorus warfare agents.

Fluorogenic dansyl-ligated gold nanoparticles for the detection of sulfur mustard by displacement assay.

The dansyl fluorophore ligated to gold nanoparticles via imidazole and amine groups affords conjugates capable of detecting micromolar concentrations of the chemical warfare agent sulfur mustard by a fluorescence switching 'ON' displacement assay.

Hydrogen bond-mediated recognition of the chemical warfare agent soman (GD).

NMR titration studies in acetonitrile-d(3)/DMSO-d(6) mixtures demonstrate that diindolylurea-based receptors can form complexes with the organophosphorus nerve agent soman in organic solution.

Preparation of aqueous core/silica shell microcapsules.

Water core/silica shell microcapsules are prepared via the hydrolysis and subsequent polycondensation of tetraethoxysilane in a surfactant stabilised water-in-oil emulsion. The relationship between preparative conditions, including pH and silane concentration, has been related to final particle structure. Furthermore, the nature of the catalyst has been found to affect the mechanism by which the shells are formed, with an interfacial polymerisation proposed for ammonium hydroxide catalysed synthesis in agreement with previous reports and a new colloidosome assembly process for sodium hydroxide catalysis.